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{{Short description|System that relates geologic strata to time}} |
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[[File:Geologic Clock with events and periods.svg|thumb|This clock representation shows some of the major units of geological time and definitive events of Earth history. The [[Hadean]] eon represents the time before the fossil record of life on Earth; its upper boundary is now regarded as 4.0 [[Year#SI prefix multipliers|Ga]] ([[1000000000 (number)|billion]] years ago).<ref name=":1">{{Cite journal |last1=Cohen |first1=K.M. |last2=Finney |first2=S.C. |last3=Gibbard |first3=P.L. |last4=Fan |first4=J.-X. |date=2013-09-01 |title=The ICS International Chronostratigraphic Chart |url=http://www.episodes.org/journal/view.html?doi=10.18814/epiiugs/2013/v36i3/002 |journal=Episodes |language=en |edition=updated |volume=36 |issue=3 |pages=199–204 |doi=10.18814/epiiugs/2013/v36i3/002 |issn=0705-3797}}</ref> Other subdivisions reflect the evolution of life; the [[Archean]] and [[Proterozoic]] are both eons, the [[Palaeozoic]], [[Mesozoic]] and [[Cenozoic]] are [[era]]s of the [[Phanerozoic]] eon. The three million year [[Quaternary]] period, the time of recognizable humans, is too small to be visible at this scale.|300x300px]] |
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[[File:GeologicTimeScale-WikiLeadImage.svg|alt=Geologic time scale with proportional representation of eons/eonothems and eras/erathems. Cenozoic is abbreviated to Cz. The image also shows some notable events in Earth's history and the general evolution of life.|thumb|Geologic time scale with proportional representation of eons/eonothems and eras/erathems. Cenozoic is abbreviated to Cz. The image also shows some notable events in Earth's history and the general evolution of life.|upright=1.35]] |
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The '''geologic time scale''' ('''GTS''') is a representation of [[time]] based on the [[Geologic record|rock record]] of [[Earth]]. It is a system of [[chronological dating]] that uses [[chronostratigraphy]] (the process of relating [[Stratum|strata]] to time) and [[geochronology]] (scientific branch of [[geology]] that aims to determine the age of rocks). It is used by primarily by [[Earth science|Earth scientists]] (including [[Geologist|geologists]], [[Paleontology|paleontologists]], [[Geophysics|geophysicists]], [[Geochemistry|geochemists]], and [[Paleoclimatology|paleoclimatologists]]) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as [[Lithology|lithologies]], [[Paleomagnetism|paleomagnetic]] properties, and [[Fossil|fossils]]. The definition of standardized international units of geologic time is the responsibility of the [[International Commission on Stratigraphy]] (ICS), a constituent body of the [[International Union of Geological Sciences]] (IUGS), whose primary objective<ref name="ICS_statutes">{{Cite web |title=Statutes |url=https://stratigraphy.org/statutes |access-date=2022-04-05 |website=stratigraphy.org |publisher=International Commission on Stratigraphy}}</ref> is to precisely define global chronostratigraphic units of the International Chronostratigraphic Chart (ICC)<ref name="ICC_Cohen_2013">{{Cite journal |last=Cohen |first=K.M. |last2=Finney |first2=S.C. |last3=Gibbard |first3=P.L. |last4=Fan |first4=J.-X. |date=2013-09-01 |title=The ICS International Chronostratigraphic Chart |url=http://www.episodes.org/journal/view.html?doi=10.18814/epiiugs/2013/v36i3/002 |journal=Episodes |language=en |edition=updated |volume=36 |issue=3 |pages=199–204 |doi=10.18814/epiiugs/2013/v36i3/002 |issn=0705-3797}}</ref> that are used to define divisions of geologic time. The chronostratigraphic divisions are in turn used to define geochronologic units.<ref name="ICC_Cohen_2013" /> |
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The '''geologic time scale''' ('''GTS''') is a system of [[chronological dating]] that classifies [[Geology|geological]] strata ([[stratigraphy]]) in time. It is used by [[geologist]]s, [[paleontology|paleontologists]], and other [[earth sciences|Earth scientists]] to describe the timing and relationships of events in geologic history. The time scale was developed through the study and observation of layers of rock and relationships as well as the times when different organisms appeared, evolved and became extinct through the study of fossilized remains and imprints. The table of geologic time spans, presented here, agrees with the [[Taxonomy (general)|nomenclature]], dates and standard color codes set forth by the [[International Commission on Stratigraphy]] (ICS). |
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While some regional terms are still in use,<ref name="GTS2012_Precambrian">{{Citation |last=Van Kranendonk |first=Martin J. |title=A Chronostratigraphic Division of the Precambrian |date=2012 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780444594259000160 |work=The Geologic Time Scale |pages=299–392 |publisher=Elsevier |language=en |doi=10.1016/b978-0-444-59425-9.00016-0 |isbn=978-0-444-59425-9 |access-date=2022-04-05 |last2=Altermann |first2=Wladyslaw |last3=Beard |first3=Brian L. |last4=Hoffman |first4=Paul F. |last5=Johnson |first5=Clark M. |last6=Kasting |first6=James F. |last7=Melezhik |first7=Victor A. |last8=Nutman |first8=Allen P.}}</ref> the table of geologic time presented on this page conforms to the [[nomenclature]], ages, and colour codes set forth by the ICS as this is the standard, reference global geologic time scale.<ref name="ICS_statutes" /> |
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==Terminology{{anchor|terminology<!-- Various redirects target this section title -->}}== |
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The largest catalogued divisions of time are intervals called ''[[Eon (geology)|eons]]''. The first eon was the [[Hadean]], starting with the formation of the Earth and lasting about 540 million years until the [[Archean]] eon, which is when the Earth had cooled enough for continents and the earliest known life to emerge. After about 1.5 billion years, oxygen generated by photosynthesizing single-celled organisms began to appear in the atmosphere, marking the beginning of the [[Proterozoic]]. Finally, the [[Phanerozoic]] eon encompasses 539 million years of diverse abundance of multicellular life, starting with the appearance of hard animal shells in the fossil record and continuing to the present. The first three eons (i.e. every eon but the Phanerozoic) can be referred to collectively as the [[Precambrian]] '''supereon'''. This is because of the significance of the [[Cambrian explosion]], a massive diversification of multicellular life forms that took place in the [[Cambrian]] period at the start of the Phanerozoic. Eons are divided into '''eras''', which are in turn divided into '''periods''', '''epochs''' and '''ages'''.<ref name="ICS_Ch9">{{Cite web |url=http://www.stratigraphy.org/upload/bak/chron.htm |title=Chapter 9. Chronostratigraphic units |series=Stratigraphic guide |publisher=[[International Commission on Stratigraphy]] |access-date=2 August 2018 |url-status=dead |archive-url=https://archive.today/20121228060135/http://www.stratigraphy.org/upload/bak/chron.htm |archive-date=28 December 2012 }}</ref><ref>{{Cite book |url=https://www.worldcat.org/oclc/860061071 |title=A dictionary of geology and earth sciences |date=2013 |publisher=Oxford University Press |others=Michael Allaby |isbn=978-0-19-174433-4 |edition=4th |location=Oxford |oclc=860061071}}</ref> A [[polarity chron]] or just "chron" can be used as a subdivision of an age, though this is not included in the ICS system. |
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== Principles == |
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{| class="wikitable" |
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{{See also|Age of Earth|History of Earth|Geological history of Earth}} |
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! Eon |
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The geologic time scale is a way of representing [[deep time]] based on events that have occurred throughout [[History of Earth|Earth's history]], a time span of about [[Age of Earth|4.54 ± 0.05 Ga]] (4.54 billion years).<ref name="Dalrymple 2001 AoE">{{cite journal |last=Dalrymple |first=G. Brent |date=2001 |title=The age of the Earth in the twentieth century: a problem (mostly) solved |journal=Special Publications, Geological Society of London |volume=190 |issue=1 |pages=205–221 |bibcode=2001GSLSP.190..205D |doi=10.1144/GSL.SP.2001.190.01.14 |s2cid=130092094}} |
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! [[Era]] |
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</ref> It chronologically organizes strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or paleontological events. For example, the [[Cretaceous–Paleogene extinction event]], marks the lower boundary of the [[Paleogene]] System/Period and thus the boundary between the [[Cretaceous]] and Paleogene Systems/Periods. For divisions prior to the [[Cryogenian]], arbitrary numeric boundary definitions (GSSAs) are used to divide geologic time. Proposals have been made to better reconcile these divisions with the rock record.<ref name="Shields_2022_pre-Cryogenian">{{Cite journal |last=Shields |first=Graham A. |last2=Strachan |first2=Robin A. |last3=Porter |first3=Susannah M. |last4=Halverson |first4=Galen P. |last5=Macdonald |first5=Francis A. |last6=Plumb |first6=Kenneth A. |last7=de Alvarenga |first7=Carlos J. |last8=Banerjee |first8=Dhiraj M. |last9=Bekker |first9=Andrey |last10=Bleeker |first10=Wouter |last11=Brasier |first11=Alexander |date=2022 |title=A template for an improved rock-based subdivision of the pre-Cryogenian timescale |url=http://jgs.lyellcollection.org/lookup/doi/10.1144/jgs2020-222 |journal=Journal of the Geological Society |language=en |volume=179 |issue=1 |pages=jgs2020–222 |doi=10.1144/jgs2020-222 |issn=0016-7649}}</ref><ref name="GTS2012_Precambrian" /> |
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! Period |
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! Extent, millions of <br/>years ago |
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Historically, regional geologic time scales were used<ref name="GTS2012_Precambrian" /> due to the litho- and biostratigraphic differences around the world in time equivalent rocks. The ICS has long worked to reconcile conflicting terminology by standardizing globally significant and identifiable stratigraphic [[Horizon (geology)|horizons]] that can be used to define the lower boundaries of chronostratigraphic units. Defining chronostratigraphic units in such a manner allows for the use of global, standardised nomenclature. The ICC represents this ongoing effort. |
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!colspan=2| Duration<br/>(millions<br/>of years) |
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The relative relationships of rocks for determining the chronostratigraphic positions use the overriding principles of: |
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* [[Superposition principle|Superposition]] – Newer rock beds will lie on top of older rock beds unless the succession has been overturned. |
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* [[Principle of original horizontality|Horizontality]] – All rock layers were originally deposited horizontally.{{Efn|It is now known that not all sedimentary layers are deposited purely horizontally, but this principle is still a useful concept.|name=horizontality|group=note}} |
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* [[Principle of lateral continuity|Lateral continuity]] – Originally deposited layers of rock extend laterally in all directions until either thinning out or being cut off by a different rock layer. |
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* Biologic succession (where applicable) – This states that each stratum in a succession contains a distinctive set of fossils. This allows for correlation of stratum even when the horizon between them is not continuous. |
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* [[Cross-cutting relationships]] – A rock feature that cuts across another feature must be younger than the rock it cuts. |
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* [[Law of included fragments|Inclusion]] – Small fragments of one type of rock but embedded in a second type of rock must have formed first, and were included when the second rock was forming. |
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* Relationships of [[Unconformity|unconformities]] – Geologic features representing periods of erosion or non-deposition, indicating non-continuous sediment deposition. |
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== Terminology{{Anchor|Terminology}} == |
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{{See also|Stratigraphy|Chronostratigraphy|Biostratigraphy|Magnetostratigraphy|Lithostratigraphy|Geochronology}} |
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The GTS is divided into chronostratigraphic units and their corresponding geochronologic units. These are represented on the ICC published by the ICS; however, regional terms are still in use in some areas. |
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<em>Chronostratigraphy</em> is the element of [[stratigraphy]] that deals with the relation between rock bodies and the relative measurement of geological time.<ref name="ICS_chronostrat">{{Cite web |title=Chapter 9. Chronostratigraphic Units |url=https://stratigraphy.org/guide/chron |access-date=2022-04-02 |website=stratigraphy.org |publisher=International Commission on Stratigraphy}}</ref> It is the process where distinct strata between defined stratigraphic horizons are assigned to represent a relative interval of geologic time. |
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A <em>chronostratigraphic unit</em>{{Anchor|Chronostratigraphic unit}} is a body of rock, layered or unlayered, that is defined between specified stratigraphic horizons which represent specified intervals of geologic time. They include all rocks representative of a specific interval of geologic time, and only this time span.<ref name="ICS_chronostrat"> |
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Eonothem, erathem, system, series, subseries, stage, and substage are the hierarchical chronostratigraphic units.<nowiki><ref name="ICS_chronostrat"> </nowiki> |
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<em>Geochronology</em> is the scientific branch of geology that aims to determine the age of rocks, fossils, and sediments either through absolute (e.g., [[radiometric dating]]) or relative means (e.g., [[Law of superposition|stratigraphic position]], [[Paleomagnetism]], [[Stable isotope ratio|stable isotope ratios]]).<nowiki><ref name="ICS_definitions"></nowiki>{{Cite web |title=Chapter 3. Definitions and Procedures |url=https://stratigraphy.org/guide/defs |access-date=2022-04-02 |website=stratigraphy.org |publisher=International Commission on Stratigraphy}}</ref> |
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A <em>geochronologic unit</em>{{Anchor|Geochronologic unit}} is a subdivision of geologic time. It is a numeric representation of an intangible property (time).<ref name="ICS_definitions" /> Eon, era, period, epoch, subepoch, age, and subage are the hierarchical geochronologic units.<ref name="ICS_chronostrat" /> <em>[[Geochronometry]]</em> is the field of geochronology that numerically quantifies geologic time.<ref name="ICS_definitions" /> |
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A <em>[[Global Boundary Stratotype Section and Point]]</em> (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundaries of stages on the geologic time scale.<ref name="ICS_GSSP">{{Cite web |title=Global Boundary Stratotype Section and Points |url=https://stratigraphy.org/gssps/ |access-date=2022-04-02 |website=stratigraphy.org |publisher=International Commission on Stratigraphy}}</ref> (Recently this has been used to define the base of a system)<ref name="Knoll_2006_Ediacaran">{{Cite journal |last=Knoll |first=Andrew |last2=Walter |first2=Malcolm |last3=Narbonne |first3=Guy |last4=Christie-Blick |first4=Nicholas |date=2006 |title=The Ediacaran Period: a new addition to the geologic time scale |url=http://doi.wiley.com/10.1080/00241160500409223 |journal=Lethaia |language=en |volume=39 |issue=1 |pages=13–30 |doi=10.1080/00241160500409223}}</ref> |
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A <em>[[Global Standard Stratigraphic Age]]</em> (GSSA)<ref name="Remane_1996_GSSP">{{Cite journal |last=Remane |first=Jürgen |last2=Bassett |first2=Michael G |last3=Cowie |first3=John W |last4=Gohrbandt |first4=Klaus H |last5=Lane |first5=H Richard |last6=Michelsen |first6=Olaf |last7=Naiwen |first7=Wang |last8=the cooperation of members of ICS |date=1996-09-01 |title=Revised guidelines for the establishment of global chronostratigraphic standards by the International Commission on Stratigraphy (ICS) |url=http://www.episodes.org/journal/view.html?doi=10.18814/epiiugs/1996/v19i3/007 |journal=Episodes |language=en |volume=19 |issue=3 |pages=77–81 |doi=10.18814/epiiugs/1996/v19i3/007 |issn=0705-3797}}</ref> is a numeric only, chronologic reference point used to define the base of geochronologic units prior to the Cryogenian. These points are arbitrarily defined.<ref name="ICS_chronostrat"> They are used where GSSPs have not yet been established. Research is ongoing to define GSSPs for the base of all units that are currently defined by GSSAs. |
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The numeric (geochronometric) representation of a geochronologic unit can, and is more frequently subject to, change when geochronology refines the geochronometry, while the equivalent chronostratigraphic unit remains the same, and their revision is less common. For example, in early 2022 the boundary between the [[Ediacaran]] and [[Cambrian]] [[Period (geologic time)|Periods]] (geochronologic units) was revised from 541 Ma to 538.8 Ma but the rock definition of the boundary (GSSP) at the base of the Cambrian, and thus the boundary between the Ediacaran and Cambrian [[System (stratigraphy)|Systems]] (chronostratigraphic units) has not changed, merely the geochronometry has been refined. |
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The numeric values on the ICC are represented by the unit [[Megaannum|Ma]] (megaannum) meaning "million [[Year|years]]", i.e., {{Period start|Jurassic}} {{Period start error|Jurassic}} Ma, the lower boundary of the [[Jurassic]] Period, is defined as 201,300,000 years old with an uncertainty of 200,000 years. Other [[Si prefix|SI prefix]] units commonly used by geologists are [[Gigaannum|Ga]] (gigaannum, billion years), and [[Kiloannums|ka]] (kiloannum, thousand years), with the latter often represented in calibrated units ([[Before Present|before present]]). |
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=== Divisions of geologic time {{Anchor|Divisions of geologic time}} === |
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An <em>eon</em> is the largest (formal) geochonologic time unit and is the equivalent of a chronostratigraphic [[eonothem]].<nowiki><ref name="dictionary_of_geology_2020"></nowiki>{{Cite book |url=https://www.worldcat.org/oclc/1137380460 |title=A dictionary of geology and earth sciences |date=2020 |others=Michael Allaby |isbn=978-0-19-187490-1 |edition=Fifth |location=Oxford |oclc=1137380460}}</ref> {{As of|2022|April|bare=}} there are three formally defined eons/eonothems: the [[Archean]], [[Proterozoic]], and [[Phanerozoic]].<ref name="ICC_Cohen_2013" /> The [[Hadean]] is an informal eon/eonothem, but is commonly used.<ref name="dictionary_of_geology_2020" /> |
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An <em>era</em> is the second largest geochonologic time unit and is the equivalent of a chronostratigraphic [[erathem]].<ref name="ICS_chronostrat" /><ref name="dictionary_of_geology_2020" /> {{As of|2022|April|bare=}} there are currently ten defined eras/erathems.<ref name="ICC_Cohen_2013" /> |
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A <em>period</em> is a major rank below an <em>era</em> and above an <em>epoch</em>. It is the geochronologic equivalent of a chronostratigraphic [[System (stratigraphy)|system]].<ref name="ICS_chronostrat" /><ref name="dictionary_of_geology_2020" />{{As of|2022|April|bare=}} there are currently 22 defined periods/systems.<ref name="ICC_Cohen_2013" /> As an exception two subperiods/subsystems are used for the [[Carboniferous]] Period/System.<ref name="ICS_chronostrat" /> |
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An <em>epoch</em> is the second smallest geochronologic unit, between a <em>period</em> and an <em>age</em>. It is the equivalent of a chronostratigraphic [[Series (stratigraphy)|series]].<ref name="ICS_chronostrat" /><ref name="dictionary_of_geology_2020" /> {{As of|2022|April|bare=}} there are currently 37 defined and one informal <em>epochs/series</em>. There are also 11 subepochs/subseries which are all within the [[Neogene]] and [[Quaternary]].<ref name="ICC_Cohen_2013" /> The use of subseries/subepochs as formal ranks/units in international chronostratigraphy was ratified in 2022.<ref name="Aubry_2022_subseries">{{Cite journal |last=Aubry |first=Marie-Pierre |last2=Piller |first2=Werner E. |last3=Gibbard |first3=Philip L. |last4=Harper |first4=David A. T. |last5=Finney |first5=Stanley C. |date=2022-03-01 |title=Ratification of subseries/subepochs as formal rank/units in international chronostratigraphy |url=http://www.episodes.org/journal/view.html?doi=10.18814/epiiugs/2021/021016 |journal=Episodes |language=en |volume=45 |issue=1 |pages=97–99 |doi=10.18814/epiiugs/2021/021016 |issn=0705-3797}}</ref> |
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An <em>age</em> is the smallest hierarchical geochonologic unit and is the equivalent of a chronostratigraphic [[Stage (stratigraphy)|stage]].<ref name="ICS_chronostrat" /><ref name="dictionary_of_geology_2020" /> {{As of|2022|April|bare=}} there are currently 96 formal and five informal ''ages/stages''.<ref name="ICC_Cohen_2013" /> |
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A <em>chron</em> is a non-hierarchical formal geochronology unit of unspecified rank and is the equivalent of a chronostratigraphic [[chronozone]].<ref name="ICS_chronostrat" /> These correlate with [[Magnetostratigraphy|magnetostratigraphic]], [[Lithostratigraphy|lithostratigraphic]], or [[Biostratigraphy|biostratigraphic]] units as they are based on previously defined stratigraphic units or geologic features. |
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The <em>Early</em> and <em>Late</em> subdivisions are used as the geochronologic equivalents of the chronostratigraphic <em>Lower</em> and <em>Upper</em>, e.g., Early [[Triassic]] Period (geochronologic unit) is used in place of Lower Triassic Series (chronostratigraphic unit). |
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In essence, it is true to say that rocks representing a given chronostratigraphic unit are that chronostratigraphic unit, and the time they were laid down in is the geochronologic unit, i.e., the rocks that represent the [[Silurian]] Series ''are'' the Silurian Series and they were deposited ''during'' the Silurian Period. |
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{| class="wikitable mw-collapsible" style = "margin-left: auto; margin-right: auto; border: none;" |
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|+Formal, hierarchical units of the geologic time scale (largest to smallest) |
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!Chronostratigraphic unit (strata) |
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!Geochronologic unit (time) |
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!Time span{{Efn|Time spans of geologic time units vary broadly, and there is no numeric limitation on the time span they can represent. They are limited by the time span of the higher rank unit they belong to, and to the chronostratigraphic boundaries they are defined by.|group=note|name=timespan}} |
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|- |
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|Eonothem |
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|rowspan=12| [[Phanerozoic]] |
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|Eon |
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|rowspan=3| [[Cenozoic]] |
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|Several hundred millions of years |
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| [[Quaternary|Quaternary (Pleistocene/Holocene)]] |
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| {{center| 2.588 to  0     }} |
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| 2.588+ |
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|rowspan=12| {{right| 538.8 }} |
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|- |
|- |
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|Erathem |
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| [[Neogene| Neogene (Miocene/Pliocene)]] |
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|Era |
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| {{center| 23.03 to  2.588 }} |
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|Tens to hundreds of millions of years |
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| {{right| 20.4 }} |
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|- |
|- |
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|System |
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| [[Paleogene| Paleogene (Paleocene/Eocene/Oligocene)]] |
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|Period |
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| {{center|   66.0 to 23.03 }} |
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|Millions of years to tens of millions of years |
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| {{right| 42.9 }} |
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|- |
|- |
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|Series |
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|rowspan=3| [[Mesozoic]] |
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|Epoch |
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| [[Cretaceous]] |
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|Hundreds of thousands of years to tens of millions of years |
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| {{center| 145.0 to 66.0   }} |
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| {{right| 79.0 }} |
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|- |
|- |
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|Subseries |
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| [[Jurassic]] |
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|Subepoch |
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| {{center| 201.3 to 145.0 }} |
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|Thousands of years to millions of years |
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| {{right| 56.3 }} |
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|- |
|- |
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|Stage |
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| [[Triassic]] |
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|Age |
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| {{center| 251.902 to 201.3   }} |
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|Thousands to years to millions of years |
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| {{right| 50.6 }} |
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|} |
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== Naming of geologic time == |
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The names of geologic time units are defined for chronostratigraphic units with the corresponding geochronologic unit sharing the same name with a change to the suffix (e.g. [[Phanerozoic]] Eonothem becomes the Phanerozoic Eon). Names of erathems in the Phanerozoic were chosen to reflect major changes of the history of life on Earth: [[Paleozoic]] (old life), [[Mesozoic]] (middle life), and [[Cenozoic]] (new life). Names of systems are diverse in origin, with some indicating chronologic position (e.g., Paleogene), while others are named for [[lithology]] (e.g., Cretaceous), [[geography]] (e.g., [[Permian]]), or are tribal (e.g., [[Ordovician]]) in origin. Most currently recognised series and subseries are named for their position within a system/series (early/middle/late); however, the ICS advocates for all new series and subseries to be named for a geographic feature in the vicinity of its [[stratotype]] or [[Type locality (geology)|type locality]]. The name of stages should also be derived from a geographic feature in the locality of its stratotype or type locality.<ref name="ICS_chronostrat" /> |
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Informally, the time before the Cambrian is often referred to as the pre-Cambrian or Precambrian (Supereon).<ref name="Shields_2022_pre-Cryogenian" />{{efn|Precambrian or pre-Cambrian is an informal geological term for time before the Cambrian period|name=Precam|group=note}} |
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{| class="wikitable mw-collapsible" style = "margin-left: auto; margin-right: auto; border: none;" |
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|+Time span and [[etymology]] of eonothem/eon names |
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!Name |
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!Time Span |
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!Etymology of name |
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|- |
|- |
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|[[Phanerozoic]] |
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|rowspan=6| [[Paleozoic]] |
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|{{Period span/brief|Phanerozoic|1}} |
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| [[Permian]] |
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|From the Greek words φανερός (''phanerós'') meaning 'visible' or 'abundant', and ζωή (''zoḯ'') meaning 'life'. |
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| {{center| 298.9   to 251.902 }} |
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| {{right| 46.9 }} |
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|- |
|- |
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|[[Proterozoic]] |
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| [[Carboniferous|Carboniferous (Mississippian/Pennsylvanian)]] |
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|{{Period span/brief|Proterozoic|1}} |
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| {{center| 358.9 to 298.9 }} |
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|From the Greek words πρότερος (''próteros'') meaning 'former' or 'earlier', and ζωή (''zoḯ'') meaning 'life'. |
|||
| {{right| 60.0 }} |
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|- |
|- |
||
| |
|[[Archean]] |
||
|{{Period span/brief|Archean|1}} |
|||
| {{center| 419.2 to 358.9 }} |
|||
|From the Greek word [[Ἀρχή|αρχή]] (''arche''), meaning 'beginning, origin'. |
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| {{right| 60.3 }} |
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|- |
|- |
||
| |
|[[Hadean]] |
||
|~{{Period span/brief|Hadean|1}} |
|||
| {{center| 443.4 to 419.2 }} |
|||
|From [[Hades]], the Greek god. |
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| {{right| 24.2 }} |
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|} |
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{| class="wikitable mw-collapsible" style = "margin-left: auto; margin-right: auto; border: none;" |
|||
|+Time span and etymology of erathem/era names |
|||
!Name |
|||
!Time Span |
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!Etymology of name |
|||
|- |
|- |
||
| |
|[[Cenozoic]] |
||
|{{Period span/brief|Cenozoic|1}} |
|||
| {{center| 485.4 to 443.4 }} |
|||
|From the Greek words καινός (''kainós'') meaning 'new', and ζωή (''zoḯ'') meaning 'life'. |
|||
| {{right| 42.0 }} |
|||
|- |
|- |
||
| |
|[[Mesozoic]] |
||
|{{Period span/brief|Mesozoic|1}} |
|||
| {{center| 538.8 to 485.4 }} |
|||
|From the Greek words μέσο (''méso'') meaning 'middle', and ζωή (''zoḯ'') meaning 'life'. |
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| {{right| 53.4 }} |
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|- |
|- |
||
|[[Paleozoic|Paleozoic]] |
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|rowspan=10| [[Proterozoic]] |
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|{{Period span/brief|Paleozoic|1}} |
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|rowspan=3| [[Neoproterozoic]] |
|||
|From the Greek words παλιός (''palaiós'') meaning 'old', and ζωή (''zoḯ'') meaning 'life'. |
|||
| [[Ediacaran]] |
|||
| {{center| 635.0 to 538.8 }} |
|||
| {{right| 96.2 }} |
|||
|rowspan=10| {{right| 1,961.2 }} |
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|- |
|- |
||
| |
|[[Neoproterozoic]] |
||
|{{Period span/brief|Neoproterozoic|1}} |
|||
| {{center| 720 to 635 }} |
|||
|From the Greek words νέος (''néos'') meaning 'new' or 'young', πρότερος (''próteros'') meaning 'former' or 'earlier', and ζωή (''zoḯ'') meaning 'life'. |
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| {{right| 85.0 }} |
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|- |
|- |
||
| |
|[[Mesoproterozoic]] |
||
|{{Period span/brief|Mesoproterozoic|1}} |
|||
| {{center| 1,000 to   720 }} |
|||
|From the Greek words μέσο (''méso'') meaning 'middle', πρότερος (''próteros'') meaning 'former' or 'earlier', and ζωή (''zoḯ'') meaning 'life'. |
|||
| {{right| 280   }} |
|||
|- |
|- |
||
|[[Paleoproterozoic]] |
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| rowspan=3| [[Mesoproterozoic]] |
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|{{Period span/brief|Paleoproterozoic|1}} |
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|[[Stenian]] |
|||
|From the Greek words παλιός (''palaiós'') meaning 'old', πρότερος (''próteros'') meaning 'former' or 'earlier', and ζωή (''zoḯ'') meaning 'life'. |
|||
| {{center| 1,200 to 1,000 }} |
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| {{right| 200   }} |
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|- |
|- |
||
|[[ |
|[[Neoarchean]] |
||
|{{Period span/brief|Neoarchean|1}} |
|||
| {{center| 1,400 to 1,200 }} |
|||
|From the Greek words νέος (''néos'') meaning 'new' or 'young', and ἀρχαῖος (''arkhaîos'') meaning 'ancient'. |
|||
| {{right| 200   }} |
|||
|- |
|- |
||
|[[ |
|[[Mesoarchean]] |
||
|{{Period span/brief|Mesoarchean|1}} |
|||
| {{center| 1,600 to 1,400 }} |
|||
|From the Greek words μέσο (''méso'') meaning 'middle', and ἀρχαῖος (''arkhaîos'') meaning 'ancient'. |
|||
| {{right| 200   }} |
|||
|- |
|- |
||
|[[Paleoarchean]] |
|||
|rowspan=4| [[Paleoproterozoic]] |
|||
|{{Period span/brief|Paleoarchean|1}} |
|||
|[[Statherian]] |
|||
|From the Greek words παλιός (''palaiós'') meaning 'old', and ἀρχαῖος (''arkhaîos'') meaning 'ancient'. |
|||
| {{center| 1,800 to 1,600 }} |
|||
| {{right| 200   }} |
|||
|- |
|- |
||
|[[ |
|[[Eoarchean]] |
||
|{{Period span/brief|Eoarchean|1}} |
|||
| {{center| 2,050 to 1,800 }} |
|||
|From the Greek words Ηώς (''Iós'') meaning 'dawn', and ἀρχαῖος (''arkhaîos'') meaning 'ancient'. |
|||
| {{right| 250   }} |
|||
|} |
|||
{| class="wikitable mw-collapsible" style = "margin-left: auto; margin-right: auto; border: none;" |
|||
|+Time span and etymology of system/period names |
|||
!Name |
|||
!Time Span |
|||
!Etymology of name |
|||
|- |
|- |
||
| |
|[[Quaternary]] |
||
|{{Period span/brief|Quaternary|1}} |
|||
| {{center| 2,300 to 2,050 }} |
|||
|First introduced by [[Jules Desnoyers]] in 1829 for sediments in [[France]]'s [[Seine]] Basin that appeared to be younger than [[Tertiary]]{{efn|The Tertiary is a now obsolete geologic system/period spanning from 66 Ma to 2.6 Ma. It has no exact equivalent in the modern ICC, but is approximately equivalent to the merged Palaeogene and Neogene systems/periods.|name=Tertiary|group=note}} rocks.<ref name="Desnoyers_1829">{{cite journal |last1=Desnoyers |first1=J. |title=Observations sur un ensemble de dépôts marins plus récents que les terrains tertiaires du bassin de la Seine, et constituant une formation géologique distincte; précédées d'un aperçu de la nonsimultanéité des bassins tertiares |journal=Annales des Sciences Naturelles |date=1829 |volume=16 |pages=171–214, 402–491 |url=https://www.biodiversitylibrary.org/item/29350#page/177/mode/1up |trans-title=Observations on a set of marine deposits [that are] more recent than the tertiary terrains of the Seine basin and [that] constitute a distinct geological formation; preceded by an outline of the non-simultaneity of tertiary basins |language=fr}} [https://www.biodiversitylibrary.org/item/29350#page/199/mode/1up From p. 193:] ''"Ce que je désirerais … dont il faut également les distinguer."'' (What I would desire to prove above all is that the series of tertiary deposits continued – and even began in the more recent basins – for a long time, perhaps after that of the Seine had been completely filled, and that these later formations – ''Quaternary'' (1), so to say – should not retain the name of alluvial deposits any more than the true and ancient tertiary deposits, from which they must also be distinguished.) However, on the very same page, Desnoyers abandoned the use of the term "Quaternary" because the distinction between Quaternary and Tertiary deposits wasn't clear. From p. 193: ''"La crainte de voir mal comprise … que ceux du bassin de la Seine."'' (The fear of seeing my opinion in this regard be misunderstood or exaggerated, has made me abandon the word "quaternary", which at first I had wanted to apply to all deposits more recent than those of the Seine basin.)</ref> |
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| {{right| 250   }} |
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|- |
|- |
||
| |
|[[Neogene|Neogene]] |
||
|{{Period span/brief|Neogene|1}} |
|||
| {{center| 2,500 to 2,300 }} |
|||
|Derived from the Greek words νέος (''néos'') meaning 'new', and γενεά (''geneá'') meaining 'genesis' or 'birth'. |
|||
| {{right| 200   }} |
|||
|- |
|- |
||
|[[Paleogene]] |
|||
|rowspan=4| [[Archean]] |
|||
|{{Period span/brief|Paleogene|1}} |
|||
| [[Neoarchean]] |
|||
|Derived from the Greek words παλιός (''palaiós'') meaning 'old', and γενεά (''geneá'') meaining 'genesis' or 'birth'. |
|||
|rowspan=4| ''Not officially divided into periods'' |
|||
| {{center| 2,800 to 2,500 }} |
|||
| {{right| 300   }} |
|||
|rowspan=4| {{right| 1,500  }} |
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|- |
|- |
||
| |
|[[Cretaceous]] |
||
|{{Period span/brief|Cretaceous|1}} |
|||
| {{center| 3,200 to 2,800 }} |
|||
|Derived from <em>Terrain Crétacé</em> used in 1822 by [[Jean d'Omalius d'Halloy]] in reference to extensive beds of [[chalk]] within the [[Paris Basin]].<ref name="d'Halloy 1822">{{cite journal | author = d’Halloy, d’O., J.-J. | year = 1822 | title = Observations sur un essai de carte géologique de la France, des Pays-Bas, et des contrées voisines |trans-title=Observations on a trial geological map of France, the Low Countries, and neighboring countries | journal = Annales des Mines | volume = 7 | pages = 353–376 | url = https://books.google.com/books?id=c-ocAQAAIAAJ&pg=PA353}} From page 373: "La troisième, qui correspond à ce qu'on a déja appelé formation de la craie, sera désigné par le nom de terrain crétacé." (The third, which corresponds to what was already called the "chalk formation", will be designated by the name "chalky terrain".)</ref> Ultimately derived from the [[Latin]] crēta meaning (''chalk''). |
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| {{right| 400   }} |
|||
|- |
|- |
||
| |
|[[Jurassic]] |
||
|{{Period span/brief|Jurassic|1}} |
|||
| {{center| 3,600 to 3,200 }} |
|||
|Named after the [[Jura Mountains]]. Originally used by [[Alexander von Humboldt]] as 'Jura Kalkstein' (Jura limestone) in 1799.<ref name="Humboldt_1799">{{Cite book |last=Humboldt |first=Alexander von |url=https://books.google.co.in/books?id=oZ5PAAAAcAAJ&newbks=0&hl=en&redir_esc=y |title=Ueber die unterirdischen Gasarten und die Mittel ihren Nachtheil zu vermindern: ein Beytrag zur Physik der praktischen Bergbaukunde |date=1799 |publisher=Vieweg |language=de}}</ref> [[Alexandre Brongniart]] was the first to publish the term Jurassic in 1829.<ref name="Brogniart_1829">{{Cite book |last=Brongniart |first=Alexandre (1770-1847) Auteur du texte |url=https://gallica.bnf.fr/ark:/12148/bpt6k255061 |title=Tableau des terrains qui composent l'écorce du globe ou Essai sur la structure de la partie connue de la terre . Par Alexandre Brongniart,... |date=1829 |language=fr}}</ref><ref name="GTS2012_Jurassic">{{Citation |last=Ogg |first=J.G. |title=Jurassic |date=2012 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780444594259000263 |work=The Geologic Time Scale |pages=731–791 |publisher=Elsevier |language=en |doi=10.1016/b978-0-444-59425-9.00026-3 |isbn=978-0-444-59425-9 |access-date=2022-05-01 |last2=Hinnov |first2=L.A. |last3=Huang |first3=C.}}</ref> |
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| {{right| 400   }} |
|||
|- |
|- |
||
| |
|[[Triassic]] |
||
|{{Period span/brief|Triassic|1}} |
|||
| {{center| 4,000 to 3,600 }} |
|||
|From the <em>Trias</em> of [[Friedrich August von Alberti]] in reference to a trio of formations widespread in southern [[Germany]]. |
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| {{right| 400   }} |
|||
|- |
|- |
||
| |
|[[Permian]] |
||
|{{Period span/brief|Permian|1}} |
|||
| ''Not officially divided into eras'' |
|||
|Named after the historical region of [[Perm Governorate|Perm]], [[Russian Empire]].<ref name="Murchison_1842">{{Cite book |last=Murchison |url=https://books.google.co.in/books?id=MDoAAAAAQAAJ&oe=UTF-8&redir_esc=y&hl=en |title=On the Geological Structure of the Central and Southern Regions of Russia in Europe, and of the Ural Mountains |last2=Murchison |first2=Sir Roderick Impey |last3=Verneuil |last4=Keyserling |first4=Graf Alexander |date=1842 |publisher=Print. by R. and J.E. Taylor |language=en}}</ref> |
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| ''Not officially divided into periods'' |
|||
|- |
|||
| From [[Age of Earth|formation of Earth]]<br/>to 4,000 |
|||
|[[Carboniferous]] |
|||
| {{right| 540   }} |
|||
|{{Period span/brief|Carboniferous|1}} |
|||
| {{right| 540   }} |
|||
|Means 'coal-bearing', from the [[Latin]] carbō (''coal'') and ferō (''to bear, carry'').<ref name="Phillips_1835">{{Cite book |last=Phillips |first=John |url=https://books.google.com.au/books?hl=en&lr=&id=-7-ZqIkYBOMC&oi=fnd&pg=PA1&ots=RzJtkyaij-&sig=V-sym2NhvCYHReO6Dlq5ILQ0ndw&redir_esc=y#v=onepage&q&f=false |title=Illustrations of the Geology of Yorkshire: Or, A Description of the Strata and Organic Remains: Accompanied by a Geological Map, Sections and Plates of the Fossil Plants and Animals ... |date=1835 |publisher=J. Murray |language=en}}</ref> |
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|- |
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|[[Devonian]] |
|||
|{{Period span/brief|Devonian|1}} |
|||
|Named after [[Devon]], England.<ref name="Sedgwick_1840">{{Cite journal |last=Sedgwick |first=A. |last2=Murchison |first2=R. I. |date=1840-01-01 |title=XLIII.--On the Physical Structure of Devonshire, and on the Subdivisions and Geological Relations of its older stratified Deposits, &c. |url=https://books.google.com/books?id=QknWzPRnVRQC&pg=PA701 |journal=Transactions of the Geological Society of London |language=en |volume=s2-5 |issue=3 |pages=633–703 |doi=10.1144/transgslb.5.3.633 |issn=2042-5295}}</ref> |
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|- |
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|[[Silurian]] |
|||
|{{Period span/brief|Silurian|1}} |
|||
|Named after the [[Celts|Celtic]] tribe, the [[Silures]].<ref name ="Murchison_1835">{{Cite journal |last=Murchison |first=Roderick Impey |date=1835 |title=VII. On the silurian system of rocks |url=https://www.tandfonline.com/doi/full/10.1080/14786443508648654 |journal=The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science |language=en |volume=7 |issue=37 |pages=46–52 |doi=10.1080/14786443508648654 |issn=1941-5966}}</ref> |
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|- |
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|[[Ordovician]] |
|||
|{{Period span/brief|Ordovician|1}} |
|||
|Named after the Celtic tribe, [[Ordovices]].<ref name="Lapworth_1879">{{Cite journal |last=Lapworth |first=Charles |date=1879 |title=I.—On the Tripartite Classification of the Lower Palæozoic Rocks |url=https://www.cambridge.org/core/product/identifier/S0016756800156560/type/journal_article |journal=Geological Magazine |language=en |volume=6 |issue=1 |pages=1–15 |doi=10.1017/S0016756800156560 |issn=0016-7568}}</ref><ref>{{Cite journal |last=Bassett |first=Michael G. |date=1979-06-01 |title=100 YEARS OF ORDOVICIAN GEOLOGY |url=http://www.episodes.org/journal/view.html?doi=10.18814/epiiugs/1979/v2i2/003 |journal=Episodes |language=en |volume=2 |issue=2 |pages=18–21 |doi=10.18814/epiiugs/1979/v2i2/003 |issn=0705-3797}}</ref> |
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|- |
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|[[Cambrian]] |
|||
|{{Period span/brief|Cambrian|1}} |
|||
|Named for [[Cambria]], a [[latin|latinised]] form of the Welsh name for [[Wales]], ''Crymu''.<ref>{{cite EB1911|wstitle=Cambria}}</ref> |
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|- |
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|[[Ediacaran]] |
|||
|{{Period span/brief|Cryogenian|1}} |
|||
|Named for the [[Ediacara Hills]]. Ediacara is possibly a corruption of the [[Kuyani]] words 'Yata Takarra' meaning hard or stony ground.<ref name="Butcher_2004">{{cite web |last=Butcher |first=Andy |date=26 May 2004 |title=Re: Ediacaran |url=http://listserv.linguistlist.org/cgi-bin/wa?A2=ind0405&L=australian-linguistics-l&D=1&P=264 |url-status=dead |archive-url=https://web.archive.org/web/20071023012434/http://listserv.linguistlist.org/cgi-bin/wa?A2=ind0405&L=australian-linguistics-l&D=1&P=264 |archive-date=23 October 2007 |access-date=19 July 2011 |work=LISTSERV 16.0 - AUSTRALIAN-LINGUISTICS-L Archives}}</ref><ref name="AHD_Ediacara_Fossil_Site">{{cite web |title=Place Details: Ediacara Fossil Site – Nilpena, Parachilna, SA, Australia |url=http://www.environment.gov.au/cgi-bin/ahdb/search.pl?mode=place_detail;place_id=105880 |url-status=live |archive-url=https://web.archive.org/web/20110603074010/http://www.environment.gov.au/cgi-bin/ahdb/search.pl?mode=place_detail;place_id=105880 |archive-date=3 June 2011 |access-date=19 July 2011 |work=Australian Heritage Database |publisher=Commonwealth of Australia |department=Department of Sustainability, Environment, Water, Population and Communities |df=dmy-all}}</ref> |
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|- |
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|[[Cryogenian]] |
|||
|{{Period span/brief|Cryogenian|1}} |
|||
|From the Greek words κρύος (''krýos'') meaning 'cold', and, γένεσις (''génesis'') meaning 'birth'.<ref name="GTS2012_Precambrian" /> |
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|- |
|||
|[[Tonian]] |
|||
|{{Period span/brief|Tonian|1}} |
|||
|From the Greek word τόνος (''tónos'') meaning 'stretch'.<ref name="GTS2012_Precambrian" /> |
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|- |
|||
|[[Stenian]] |
|||
|{{Period span/brief|Stenian|1}} |
|||
|From the Greek word στενός (''stenós'') meaning 'narrow'.<ref name="GTS2012_Precambrian" /> |
|||
|- |
|||
|[[Ectasian]] |
|||
|{{Period span/brief|Ectasian|1}} |
|||
|From the Greek word ἔκτᾰσῐς (''éktasis'') meaning 'extension'.<ref name="GTS2012_Precambrian" /> |
|||
|- |
|||
|[[Calymmian]] |
|||
|{{Period span/brief|Calymmian|1}} |
|||
|From the Greek word κάλυμμᾰ (''kálumma'') meaning 'cover'.<ref name="GTS2012_Precambrian" /> |
|||
|- |
|||
|[[Statherian]] |
|||
|{{Period span/brief|Statherian|1}} |
|||
|From the Greek word σταθερός (''statherós'') meaning 'stable'.<ref name="GTS2012_Precambrian" /> |
|||
|- |
|||
|[[Orosirian]] |
|||
|{{Period span/brief|Orosirian|1}} |
|||
|From the Greek word ὀροσειρά (''oroseirá'') meaning 'mountain range'.<ref name="GTS2012_Precambrian" /> |
|||
|- |
|||
|[[Rhyacian]] |
|||
|{{Period span/brief|Rhyacian|1}} |
|||
|From the Greek word ῥύαξ (''rhýax'') meaning 'stream of lava'.<ref name="GTS2012_Precambrian" /> |
|||
|- |
|||
|[[Siderian]] |
|||
|{{Period span/brief|Siderian|1}} |
|||
|From the Greek word σίδηρος (''sídiros'') meaning '[[iron]]'.<ref name="GTS2012_Precambrian" /> |
|||
|} |
|} |
||
== History of the geologic time scale == |
|||
{{Geology to Paleobiology}} |
|||
{{See also|History of geology|History of paleontology}} |
|||
=== Early history === |
|||
While a modern geological time scale was not formulated until 1911<ref name="Holmes_1911">{{Cite journal |date=1911-06-09 |title=The association of lead with uranium in rock-minerals, and its application to the measurement of geological time |url=https://doi.org/10.1098/rspa.1911.0036 |journal=Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character |volume=85 |issue=578 |pages=248–256 |doi=10.1098/rspa.1911.0036 |issn=0950-1207}}</ref> by [[Arthur Holmes]], the broader concept that rocks and time are related can be traced back to (at least) the [[Philosopher|philosophers]] of [[Ancient Greece]]. [[Xenophanes|Xenophanes of Colophon]] (c. 570–487 [[Common era|BCE]]) observed rock beds with fossils of shells located above the sea-level, viewed them as once living organisms, and used this to imply an unstable relationship in which the sea had at times [[Marine transgression|transgressed]] over the land and at other times had [[Marine regression|regressed]].<ref name="Fischer_2009">{{Cite journal |last=Fischer |first=Alfred G. |last2=Garrison |first2=Robert E. |date=2009 |title=The role of the Mediterranean region in the development of sedimentary geology: a historical overview |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1365-3091.2008.01009.x |journal=Sedimentology |language=en |volume=56 |issue=1 |pages=3–41 |doi=10.1111/j.1365-3091.2008.01009.x}}</ref> This view was shared by a few of Xenophanes' contemporaries and those that followed, including [[Aristotle]] (384–322 BCE) who (with additional observations) reasoned that the positions of land and sea had changed over long periods of time. The concept of [[deep time]] was also recognised by [[History of science and technology in China|Chinese naturalist]] [[Shen Kuo]]<ref name="Nathan 1995">{{Cite book |last=Nathan. |first=Sivin, |url=http://worldcat.org/oclc/956775994 |title=Science in ancient China : researches and reflections |date=1995 |publisher=Variorum |isbn=0-86078-492-4 |oclc=956775994}}</ref> (1031–1095) and [[Islam|Islamic]] [[scientist]]-philosophers, notably the [[Brethren of Purity|Brothers of Purity]], who wrote on the processes of stratification over the passage of time in their [[Encyclopedia of the Brethren of Purity|treatises]].<ref name="Fischer_2009" /> Their work likely inspired that of the 11th-century [[Persians|Persian]] [[polymath]] [[Avicenna]] (Ibn Sînâ, 980–1037) who wrote in ''[[The Book of Healing]]'' (1027) on the concept of stratification and superposition, pre-dating [[Nicolas Steno]] by more than six centuries.<ref name="Fischer_2009" /> Avicenna also recognised fossils as "petrifications of the bodes of plants and animals",<ref name="Adams_1938">{{Cite book |last=Adams |first=Frank D. |url=http://worldcat.org/oclc/165626104 |title=The Birth and Development of the Geological Sciences |date=1938 |publisher=Williams & Wilkins |isbn=0-486-26372-X |oclc=165626104}}</ref> with the 13th-century [[Dominican Order|Dominican]] [[bishop]] [[Albertus Magnus]] (c. 1200–1280) extending this into a theory of a petrifying fluid.<ref name="Rudwick_1985">{{Cite book |last=Rudwick |first=M. J. S. |url=https://www.worldcat.org/oclc/11574066 |title=The meaning of fossils : episodes in the history of palaeontology |date=1985 |publisher=University of Chicago Press |isbn=0-226-73103-0 |edition= |location=Chicago |oclc=11574066}}</ref>{{verification needed|date=April 2022|reason=The reference to Albertus Magnus and a petrifying fluid is a hangover from the original [[Geologic time scale]] article. I cannot confidently corroborate the source material against this statement.}} These works appeared to have little influence on [[Scholar|scholars]] in [[Middle Ages|Medieval Europe]] who looked to the [[Bible]] to explain the origins of fossils and sea-level changes, often attributing these to the '[[Genesis flood narrative|Deluge]]', including [[Restoro d'Arezzo|Ristoro d'Arezzo]] in 1282.<ref name="Fischer_2009" /> It was not until the [[Italian Renaissance]] when [[Leonardo da Vinci]] (1452–1519) would reinvigorate the relationships between stratification, relative sea-level change, and time, denouncing attribution of fossils to the 'Deluge':<ref name="McCurdy_1938">{{Cite book |last=McCurdy |first=Edward |url=https://www.worldcat.org/search?q=no:2233803&qt=advanced&dblist=638 |title=The notebooks of Leonardo da Vinci |date=1938 |publisher=Reynal & Hitchcock |location=New York |language=English |oclc=2233803}}</ref><ref name="Fischer_2009" /> |
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{{blockquote|text=Of the stupidity and ignorance of those who imagine that these creatures were carried to such places distant from the sea by the Deluge...Why do we find so many fragments and whole shells between the different layers of stone unless they had been upon the shore and had been covered over by earth newly thrown up by the sea which then became petrified? And if the above-mentioned Deluge had carried them to these places from the sea, you would find the shells at the edge of one layer of rock only, not at the edge of many where may be counted the winters of the years during which the sea multiplied the layers of sand and mud brought down by the neighboring rivers and spread them over its shores. And if you wish to say that there must have been many deluges in order to produce these layers and the shells among them it would then become necessary for you to affirm that such a deluge took place every year.}} |
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{{collapse top|Visual timelines including ages}} |
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{{Timeline geological timescale}} |
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{{collapse bottom}} |
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These views of da Vinci remained unpublished, and thus lacked influence at the time; however, questions of fossils and their significance were pursued and, while views against [[Genesis creation narrative|Genesis]] were not readily accepted and dissent from [[Religion|religious]] doctrine was in some places unwise, scholars such as [[Girolamo Fracastoro]] shared da Vinci's views, and found the attribution of fossils to the 'Deluge' absurd.<ref name="Fischer_2009" /> |
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Corresponding to eons, eras, periods, epochs and ages, the terms "[[eonothem]]", "[[erathem]]", "[[system (stratigraphy)|system]]", "[[series (stratigraphy)|series]]", "[[stage (stratigraphy)|stage]]" are used to refer to the layers of rock that belong to these stretches of geologic time in Earth's history. |
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=== Establishment of primary principles === |
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Geologists qualify these units as "early", "mid", and "late" when referring to time, and "lower", "middle", and "upper" when referring to the corresponding rocks. For example, the Lower Jurassic Series in [[chronostratigraphy]] corresponds to the Early Jurassic Epoch in [[geochronology]].<ref name=":1" /> The adjectives are capitalized when the subdivision is formally recognized, and lower case when not; thus "early Miocene" but "Early Jurassic." |
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Niels Stensen, more commonly known as Nicolas Steno (1638–1686), is credited with establishing four of the guiding principles of stratigraphy.<ref name="Fischer_2009" /> In ''De solido intra solidum naturaliter contento dissertationis prodromus'' Steno states:<ref name="Steno_1669">{{Cite book |last=Steno |first=Nicolaus |url=https://books.google.de/books?id=xz28AAAAIAAJ&printsec=frontcover&hl=de#v=onepage&q&f=false |title=Nicolai Stenonis de solido intra solidvm natvraliter contento dissertationis prodromvs ad serenissimvm Ferdinandvm II ... |date=1669 |publisher=W. Junk |language=la}}</ref><ref name="Kardel_2018">{{Citation |last=Kardel |first=Troels |title=2.27 The Prodromus to a Dissertation on a Solid Naturally Contained Within a Solid |date=2018 |url=http://link.springer.com/10.1007/978-3-662-55047-2_38 |work=Nicolaus Steno |pages=763–825 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |language=en |doi=10.1007/978-3-662-55047-2_38 |isbn=978-3-662-55046-5 |access-date=2022-04-20 |last2=Maquet |first2=Paul}}</ref> |
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<blockquote> |
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* When any given stratum was being formed, all the matter resting on it was fluid and, therefore, when the lowest stratum was being formed, none of the upper strata existed. |
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* ...strata which are either perpendicular to the horizon or inclined to it were at one time parallel to the horizon. |
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* When any given stratum was being formed, it was either encompassed at its edges by another solid substance or it covered the whole globe of the earth. Hence, it follows that wherever bared edges of strata are seen, either a continuation of the same strata must be looked for or another solid substance must be found that kept the material of the strata from being dispersed. |
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* If a body or discontinuity cuts across a stratum, it must have formed after that stratum. |
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</blockquote> |
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Respectively, these are the principles of superposition, original horizontality, lateral continuity, and cross-cutting relationships. From this Steno reasoned that strata were laid down in succession and inferred relative time (in Steno's belief, time from [[Creation myth|Creation]]). While Steno's principles were simple and attracted much attention, applying them proved challenging.<ref name="Fischer_2009" /> These basic principles, albeit with improved and more nuanced interpretations, still form the foundational principles of determining correlation of strata relative geologic time. |
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Over the course of the 18th-century geologists realised that: |
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===Era definitions=== |
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* Sequences of strata often become eroded, distorted, tilted, or even inverted after deposition |
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The [[Phanerozoic Eon]] is divided into three eras: the [[Paleozoic]], [[Mesozoic]], and [[Cenozoic]] (meaning "old life", "middle life" and "recent life") that represent the major stages in the macroscopic [[fossil record]]. These eras are separated by catastrophic [[extinction]] boundaries: the [[Permian–Triassic extinction event|P-T boundary]] between the Paleozoic and the Mesozoic, and the [[Cretaceous–Paleogene boundary|K-Pg boundary]] between the Mesozoic and the Cenozoic.<ref name="Erwin_1994">{{Cite journal |last=Erwin D.H. |year=1994 |title=The Permo–Triassic Extinction |url=https://www.cornellcollege.edu/geology/courses/Greenstein/paleo/Permo_Tr.pdf |journal=Nature |volume=367 |issue=6460 |pages=231–236 |doi=10.1038/367231a0 |bibcode=1994Natur.367..231E |s2cid=4328753 |access-date=4 September 2021 |archive-date=8 February 2018 |archive-url=https://web.archive.org/web/20180208124206/https://www.cornellcollege.edu/geology/courses/Greenstein/paleo/Permo_Tr.pdf |url-status=dead }}</ref> There is evidence that the P-T boundary was caused by the eruption of the [[Siberian Traps]], and the K-Pg boundary was caused by the [[meteorite impact]] that created the [[Chicxulub crater]].<ref>{{Cite web|title=The KT extinction|url=https://ucmp.berkeley.edu/education/events/cowen1b.html|access-date=2022-02-08|website=ucmp.berkeley.edu}}</ref> |
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* Strata laid down at the same time in different areas could have entirely different appearances |
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* The strata of any given area represented only part of Earth's long history |
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=== Formulation of a modern geologic time scale === |
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The [[Hadean]], [[Archean]] and [[Proterozoic]] eons were as a whole formerly called the [[Precambrian]]. This covered the four billion years of Earth history prior to the appearance of hard-shelled animals. More recently, the Archean has been divided into four eras and the Proterozoic has been divided into three eras. |
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The apparent, earliest formal division of the geologic record with respect to time was introduced by [[Thomas Burnet]] who applied a two-fold terminology to mountains by identifying "''montes primarii''" for rock formed at the time of the 'Deluge', and younger "''monticulos secundarios"'' formed later from the debris of the "''primarii"''.<ref name="Burnet_1681">{{Cite book |last=Burnet |first=Thomas |title=Telluris Theoria Sacra: orbis nostri originen et mutationes generales, quasi am subiit aut olim subiturus est, complectens. Libri duo priores de Diluvio & Paradiso |publisher=G. Kettiby |year=1681 |location=London |language=la}}</ref><ref name="Fischer_2009" /> This attribution to the 'Deluge', while questioned earlier by the likes of da Vinci, was the foundation of [[Abraham Gottlob Werner]]'s (1749–1817) [[Neptunism]] theory in which all rocks precipitated out of a single flood.<ref name="Werner_1787">{{Cite book |last=Werner |first=Abraham Gottlob |url=https://archive.org/details/bub_gb_DdhAAAAAcAAJ |title=Kurze Klassifikation und Beschreibung der verschiedenen Gebirgsarten |date=1787 |publisher=Walther |others= |location=Dresden |language=de}}</ref> A competing theory, [[Plutonism]], was developed by [[Anton Moro]] (1687–1784) and also used primary and secondary divisions for rock units.<ref name="Moro_1740">{{Cite book |last=Moro |first=Anton Lazzaro |url=https://books.google.com.au/books?id=03RBAAAAYAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false |title=De'crostacei e degli altri marini corpi che si truovano su'monti |date=1740 |publisher=Appresso Stefano Monti |language=it}}</ref><ref name="Fischer_2009" /> In this early version of the Plutonism theory, the interior of Earth was seen as hot, and this drove the creation of primary igneous and metamorphic rocks and secondary rocks formed contorted and fossiliferous sediments. These primary and secondary divisions were expanded on by [[Giovanni Targioni Tozzetti]] (1712–1783) and [[Giovanni Arduino (geologist)|Giovanni Arduino]] (1713–1795) to include tertiary and quaternary divisions.<ref name="Fischer_2009" /> These divisions were used to describe both the time during which the rocks were laid down, and the collection of rocks themselves (i.e., it was correct to say Tertiary rocks, and Tertiary Period). Only the Quaternary division is retained in the modern geologic time scale, while the Tertiary division was in use until the early 21st century. The Neputism and Plutonism theories would compete into the early [[19th century]] with a key driver for resolution of this debate being the work of [[James Hutton]] (1726–1797), in particular his ''[[Theory of the Earth]]'', first presented before the [[Royal Society of Edinburgh]] in 1785.<ref name="Hutton_1788">{{Cite journal |last=Hutton |first=James |date=1788 |title=X. Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe . |url=https://www.cambridge.org/core/product/identifier/S0080456800029227/type/journal_article |journal=Transactions of the Royal Society of Edinburgh |language=en |volume=1 |issue=2 |pages=209–304 |doi=10.1017/S0080456800029227 |issn=0080-4568}}</ref><ref name="Hutton_1795v1">{{Cite book |last=Hutton |first=James |url=https://www.gutenberg.org/ebooks/12861 |title=Theory of the Earth |year=1795 |volume=1 |location=Edinburgh}}</ref><ref name="Hutton_1795v2">{{Cite book |last=Hutton |first=James |url=https://www.gutenberg.org/ebooks/14179 |title=Theory of the Earth |year=1795 |volume=2 |location=Edinburgh}}</ref> Hutton's theory would later become known as [[uniformitarianism]], popularised by [[John Playfair]]<ref name="Playfair_1802">{{Cite book |last=Playfair |first=John |url=http://archive.org/details/NHM104643 |title=Illustrations of the Huttonian theory of the earth |date=1802 |publisher=Neill & Co |others=Digitised by London Natural History Museum Library |location=Edinburgh}}</ref> (1748–1819) and later [[Charles Lyell]] (1797–1875) in his ''[[Principles of Geology]]''.<ref name="Lyell_1832v1">{{Cite book |last=Lyell |first=Sir Charles |url=https://books.google.com/books?id=mmIOAAAAQAAJ&newbks=0&hl=en |title=Principles of Geology: Being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes Now in Operation |date=1832 |publisher=John Murray |volume=1 |location=London |language=en}}</ref><ref name="Lyell_1832v2">{{Cite book |last=Lyell |first=Sir Charles |url=https://books.google.com/books?id=TlwPAAAAYAAJ&newbks=0&hl=en |title=Principles of Geology: Being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes Now in Operation |date=1832 |publisher=John Murray |volume=2 |location=London |language=en}}</ref><ref name="Lyell_1834v3">{{Cite book |last=Lyell |first=Sir Charles |url=https://books.google.com/books?id=UrIJAAAAIAAJ&newbks=0&hl=en |title=Principles of Geology: Being an Inquiry how for the Former Changes of the Earth's Surface are Referrable to Causes Now in Operation |date=1834 |publisher=John Murray |volume=3 |location=London |language=en}}</ref> Their theories strongly contested the 6,000 year age of the Earth as suggested determined by [[James Ussher]] via Biblical chronology that was accepted at the time by western religion. Instead, using geological evidence, they contested Earth to be much older, cementing the concept of deep time. |
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During the early 19th century [[William Smith (geologist)|William Smith]], [[Georges Cuvier]], [[Jean Baptiste Julien d'Omalius d'Halloy|Jean d'Omalius d'Halloy]], and [[Alexandre Brongniart]] pioneered the systematic division of rocks by stratigraphy and fossil assemblages. These geologists began to use the local names given to rock units in a wider sense, correlating strata across national and continental boundaries based on their similarity to each other. Many of the names below erathem/era rank in use on the modern ICC/GTS were determined during the early to mid-19th century. |
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===Period definitions=== |
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The twelve currently recognised periods of the present eon – the [[Phanerozoic]] – are defined by the [[International Commission on Stratigraphy]] (ICS) by reference to the [[stratigraphy]] at particular locations around the world.<ref name=ICS>{{cite web |title=International Commission on Stratigraphy |url=https://stratigraphy.org/ |access-date=31 July 2021 |date=2021}}</ref> In 2004 the [[Ediacaran]] Period of the latest [[Precambrian]] was defined in similar fashion, and was the first such newly designated period in 130 years.<ref name=Knoll2004>{{cite journal |
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| author = Knoll, A. H. |
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| date = 30 July 2004 |
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| title = A new period for the geologic time scale |
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| journal = Science |
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| volume = 305 |
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| issue = 5684 |
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| pages = 621–622 |
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| doi = 10.1126/science.1098803 |
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| url = http://www.stratigraphy.org/bak/ediacaran/Knoll_et_al_2004b.pdf |
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| pmid = 15286353 |
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| last2 = Walter |
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| first2 = MR |
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| last3 = Narbonne |
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| first3 = G. M |
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| last4 = Christie-Blick |
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| first4 = N |
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| s2cid = 32763298 |
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}}</ref> |
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=== The advent of geochronometry === |
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A consequence of this approach to the Phanerozoic periods is that the ages of their beginnings and ends can change from time to time as the absolute age of the chosen rock sequences, which define them, is more precisely determined.<ref name="The Geologic Time Scale">{{cite book|editor1-first=Felix|editor1-last=Gradstein|editor2-first=James|editor2-last=Ogg|editor3-first=Mark|editor3-last=Schmitz|editor4-first=Gabi|editor4-last=Ogg|title=The Geologic Time Scale |publisher=Elsevier B.V.|date=2012|isbn=978-0-444-59425-9}}</ref> |
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During the 19th century, the debate regarding Earth's age was renewed, with geologists estimating ages based on [[denudation]] rates and sedimentary thicknesses or ocean chemistry, and physicists determining ages for the cooling of the Earth or the Sun using basic [[thermodynamics]] or orbital physics.<ref name="Dalrymple 2001 AoE" /> These estimations varied from 15,000 million years to 0.075 million years depending on method and author, but the estimations of [[William Thomson, 1st Baron Kelvin|Lord Kelvin]] and [[Clarence King]] were held in high regard at the time due to their pre-eminence in physics and geology. All of these early geochronometric determinations would later prove to be incorrect. |
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The discovery of [[radioactive decay]] by [[Henri Becquerel]], [[Marie Curie]], and [[Pierre Curie]] laid the ground work for radiometric dating, but the knowledge and tools required for accurate determination of radiometric ages would not be in place until the mid-1950s.<ref name="Dalrymple 2001 AoE" /> Early attempts at determining ages of uranium minerals and rocks by [[Ernest Rutherford]], [[Bertram Boltwood]], [[Robert Strutt, 4th Baron Rayleigh|Robert Strutt]], and Arthur Holmes, would culminate in what is considered the first international geological time scales by Holmes in 1911 and 1913.<ref name="Holmes_1911" /><ref name="Holmes 1913">{{Cite book |last=Holmes |first=Arthur |url=http://archive.org/details/ageofearth00holmuoft |title=The age of the earth |date=1913 |publisher=London, Harper |others=Gerstein - University of Toronto}}</ref><ref name="Lewis_2001">{{Cite journal |last=Lewis |first=Cherry L. E. |date=2001 |title=Arthur Holmes’ vision of a geological timescale |url=http://sp.lyellcollection.org/lookup/doi/10.1144/GSL.SP.2001.190.01.10 |journal=Geological Society, London, Special Publications |language=en |volume=190 |issue=1 |pages=121–138 |doi=10.1144/GSL.SP.2001.190.01.10 |issn=0305-8719}}</ref> The discovery of [[Isotope|isotopes]] in 1913<ref>{{Cite journal |last=Soddy |first=Frederick |date=1913-12-04 |title=Intra-atomic Charge |url=https://www.nature.com/articles/092399c0 |journal=Nature |language=en |volume=92 |issue=2301 |pages=399–400 |doi=10.1038/092399c0 |issn=0028-0836}}</ref> by [[Frederick Soddy]], and the developments in [[mass spectrometry]] pioneered by [[Francis William Aston]], [[Arthur Jeffrey Dempster]], and [[Alfred O. C. Nier]] during the early to mid-[[20th century]] would finally allow for the accurate determination of radiometric ages, with Holmes publishing several revisions to his ''geological time-scale'' with his final version in 1960.<ref name="Dalrymple 2001 AoE" /><ref name="Lewis_2001" /><ref name="Holmes_1960">{{Cite journal |last=Holmes |first=A. |date=1959-01-01 |title=A revised geological time-scale |url=http://trned.lyellcollection.org/cgi/doi/10.1144/transed.17.3.183 |journal=Transactions of the Edinburgh Geological Society |language=en |volume=17 |issue=3 |pages=183–216 |doi=10.1144/transed.17.3.183 |issn=0371-6260}}</ref><ref name="GTS1960">{{Cite journal |date=1960 |title=A Revised Geological Time-Scale |url=https://www.nature.com/articles/187027d0 |journal=Nature |language=en |volume=187 |issue=4731 |pages=27–28 |doi=10.1038/187027d0 |issn=0028-0836}}</ref> |
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The set of rocks ([[sedimentary rock|sedimentary]], [[igneous rock|igneous]] or [[metamorphic rock|metamorphic]]) formed during a period belong to a [[chronostratigraphic]] unit called a [[System (stratigraphy)|system]].{{sfn|Jackson|1997|loc="system [stratig]"}} For example, the "Jurassic System" of rocks was formed during the "Jurassic Period" (between 201 and 145 million years ago).{{sfn|Jackson|1997|loc="system [stratig]"}} |
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=== Modern international geologic time scale === |
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==Principles== |
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The establishment of the IUGS in 1961<ref name="Harrison_1978">{{Cite journal |last=Harrison |first=James M. |date=1978-03-01 |title=THE ROOTS OF IUGS |url=http://dx.doi.org/10.18814/epiiugs/1978/v1i1/005 |journal=Episodes |volume=1 |issue=1 |pages=20–23 |doi=10.18814/epiiugs/1978/v1i1/005 |issn=0705-3797}}</ref> and acceptance of the Commission on Stratigraphy (applied in 1965)<ref name="ICS_statutes_1986">{{Cite book |last=International Union of Geological Sciences. Commission on Stratigraphy |url=https://www.worldcat.org/oclc/14352783 |title=Guidelines and statutes of the International Commission on Stratigraphy (ICS) |date=1986 |publisher=Herausgegeben von der Senckenbergischen Naturforschenden Gesellschaft |others=J. W. Cowie |isbn=3-924500-19-3 |location=Frankfurt a.M. |oclc=14352783}}</ref> to become a member commission of IUGS led to the founding of the ICS. One of the primary objectives of the ICS is "the establishment, publication and revision of the ICS International Chronostratigraphic Chart which is the standard, reference global Geological Time Scale to include the ratified Commission decisions".<ref name="ICS_statutes" /> |
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Evidence from [[radiometric dating]] indicates that Earth is about [[age of the Earth|4.54 billion years old]].<ref name="USGS1997">{{cite web |
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| date=1997 | title=Age of the Earth |
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| url=http://pubs.usgs.gov/gip/geotime/age.html |
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| publisher=U.S. Geological Survey |
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| access-date=2006-01-10 |
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| archive-url= https://web.archive.org/web/20051223072700/http://pubs.usgs.gov/gip/geotime/age.html| archive-date= 23 December 2005 | url-status= live}}</ref><ref>{{cite journal |
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| last=Dalrymple | first=G. Brent |
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| title=The age of the Earth in the twentieth century: a problem (mostly) solved | journal=Special Publications, Geological Society of London |
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| date=2001 | volume=190 |
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| issue=1 | pages=205–221 |
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| doi=10.1144/GSL.SP.2001.190.01.14 |bibcode = 2001GSLSP.190..205D | s2cid=130092094 |
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}} |
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</ref> The geology or ''[[deep time]]'' of Earth's past has been organized into various units according to events that are thought to have taken place. Different spans of time on the GTS are usually marked by corresponding [[Stratigraphy|changes in the composition of strata]] which indicate major geological or [[paleontology|paleontological]] events, such as [[mass extinction]]s. For example, the boundary between the [[Cretaceous]] period and the [[Paleogene]] period is defined by the [[Cretaceous–Paleogene extinction event]], which marked the demise of the non-avian [[dinosaur]]s as well as many other groups of life. Older time spans, which predate the reliable fossil record (before the [[Proterozoic eon]]), are defined by their absolute age. |
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Following on from Holmes, several ''A Geological Time Scale'' books were published in 1982,<ref name="GTS82">{{Cite book |url=https://www.worldcat.org/oclc/8387993 |title=A geologic time scale |date=1982 |publisher=Cambridge University Press |others=W. B. Harland |isbn=0-521-24728-4 |location=Cambridge [England] |oclc=8387993}}</ref> 1989,<ref name="GTS1989">{{Cite book |url=https://www.worldcat.org/oclc/20930970 |title=A geologic time scale 1989 |date=1990 |publisher=Cambridge University Press |others=W. B. Harland |isbn=0-521-38361-7 |location=Cambridge |oclc=20930970}}</ref> 2004,<ref name="GTS2004">{{Cite book |url=https://www.worldcat.org/oclc/60770922 |title=A geologic time scale 2004 |date=2004 |publisher=Cambridge University Press |others=F. M. Gradstein, James G. Ogg, A. Gilbert Smith |isbn=0-511-08201-0 |location=Cambridge, UK |oclc=60770922}}</ref> 2008,<ref name="GTS2008">{{Cite journal |last=Gradstein |first=Felix M. |last2=Ogg |first2=James G. |last3=van Kranendonk |first3=Martin |date=2008-07-23 |title=On the Geologic Time Scale 2008 |url=http://www.schweizerbart.de/papers/nos/detail/43/63825/On_the_Geologic_Time_Scale_2008?af=crossref |journal=Newsletters on Stratigraphy |language=en |volume=43 |issue=1 |pages=5–13 |doi=10.1127/0078-0421/2008/0043-0005 |issn=0078-0421}}</ref> 2012,<ref name="GTS2012">{{Cite book |url=https://www.worldcat.org/oclc/808340848 |title=The geologic time scale 2012. Volume 2 |date=2012 |publisher=Elsevier |others=F. M. Gradstein |isbn=0-444-59448-5 |edition=1st |location=Amsterdam |oclc=808340848}}</ref> 2016,<ref name="GTS2016">{{Cite book |last=Ogg |first=James G. |url=https://www.worldcat.org/oclc/949988705 |title=A concise geologic time scale 2016 |date=2016 |publisher=Elsevier |others=Gabi Ogg, F. M. Gradstein |isbn=0-444-59468-X |location=Amsterdam, Netherlands |oclc=949988705}}</ref> and 2020.<ref name="GTS2020">{{Cite book |url=https://www.worldcat.org/oclc/1224105111 |title=Geologic time scale 2020 |date=2020 |others=F. M. Gradstein, James G. Ogg, Mark D. Schmitz, Gabi Ogg |isbn=0-12-824361-9 |location=Amsterdam, Netherlands |oclc=1224105111}}</ref> However, since 2013, the ICS has taken responsibility for producing and distributing the ICC citing the commercial nature, independent creation, and lack oversight of the by ICS on the prior published GTS versions (GTS books prior to 2013) although these versions were published in close association with the ICS.<ref name="ICC_Cohen_2013" /> Subsequent ''Geologic Time Scale'' books (2016<ref name="GTS2016" /> and 2020<ref name="GTS2020"/>) are commercial publications with no oversight from the ICS, and do not entirely conform to the chart produced by the ICS. The ICS produced GTS charts are versioned (year/month) beginning at v2013/01. At least one new version is published each year incorporating any changes ratified by the ICS since the prior version. |
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Geologic units from the same time but different parts of the world often are not similar and contain different fossils, so the same time-span was historically given different names in different locales. For example, in North America, the Lower [[Cambrian]] is called the Waucoban series that is then subdivided into zones based on the succession of [[trilobita|trilobites]]. In [[East Asia]] and [[Siberia]], the same unit is split into [[Alexian]], [[Atdabanian]], and [[Botomian]] stages. A key aspect of the work of the International Commission on Stratigraphy is to reconcile this conflicting terminology and define universal [[Horizon (geology)|horizons]] that can be used around the world.<ref>{{cite web|url=http://www.stratigraphy.org/bak/status.htm#_2.__PURPOSE_AND_OBJECTIVES|title=Statutes of the International Commission on Stratigraphy|access-date=26 November 2009}}</ref> |
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{{Timeline geological timescale}} |
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Some other [[Planet#Solar System|planets]] and [[Natural satellite|moons]] in the Solar System have sufficiently rigid structures to have preserved records of their own histories, for example, [[Geology of Venus|Venus]], [[Geology of Mars|Mars]] and the [[Geology of the Moon|Earth's Moon]]. Dominantly fluid planets, such as the [[gas giant]]s, do not comparably preserve their history. Apart from the [[Late Heavy Bombardment]], events on other planets probably had little direct influence on the Earth, and events on Earth had correspondingly little effect on those planets. Construction of a time scale that links the planets is, therefore, of only limited relevance to the Earth's time scale, except in a Solar System context. The existence, timing, and terrestrial effects of the Late Heavy Bombardment are still a matter of debate.{{efn|Not enough is known about extra-solar planets for worthwhile speculation.}} |
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== |
== Major proposed revisions to the ICC == |
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=== Proposed Anthropocene Series/Epoch === |
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{{Life timeline}} |
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{{Main|Anthropocene}} |
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{{Main|History of geology|History of paleontology}} |
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First suggested in 2000,<ref =name"Crutzen_2021">{{Citation |last=Crutzen |first=Paul J. |title=The ‘Anthropocene’ (2000) |date=2021 |url=https://link.springer.com/10.1007/978-3-030-82202-6_2 |work=Paul J. Crutzen and the Anthropocene: A New Epoch in Earth’s History |volume=1 |pages=19–21 |editor-last=Benner |editor-first=Susanne |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-82202-6_2 |isbn=978-3-030-82201-9 |access-date=2022-04-15 |last2=Stoermer |first2=Eugene F. |editor2-last=Lax |editor2-first=Gregor |editor3-last=Crutzen |editor3-first=Paul J. |editor4-last=Pöschl |editor4-first=Ulrich}}</ref> the <em>Anthropocene</em> is a proposed epoch/series for the most recent time in Earth's history. While still informal, it is a widely used term to denote the present geologic time interval, in which many conditions and processes on Earth are profoundly altered by human impact.<ref>{{Cite web |title=Working Group on the ‘Anthropocene’ {{!}} Subcommission on Quaternary Stratigraphy |url=https://quaternary.stratigraphy.org/working-groups/anthropocene/ |archive-url=https://web.archive.org/web/20220407193255/https://quaternary.stratigraphy.org/working-groups/anthropocene/ |archive-date=2022-04-07 |access-date=2022-04-17 |language=en-US}}</ref> {{As of|2022|April}} the Anthropocene has not been ratified by the ICS; however, in May 2019 the [[Anthropocene Working Group]] voted in favour of submitting a formal proposal to the ICS for the establishment of the Anthropocene Series/Epoch.<ref name="Subramanian_2019">{{Cite journal |last=Subramanian |first=Meera |date=2019-05-21 |title=Anthropocene now: influential panel votes to recognize Earth’s new epoch |url=http://www.nature.com/articles/d41586-019-01641-5 |journal=Nature |language=en |pages=d41586–019–01641-5 |doi=10.1038/d41586-019-01641-5 |issn=0028-0836}}</ref> However, the definition of the Anthropocene as a geologic time period rather than a geologic event remains controversial and difficult.<ref name="Gibbard_2021">{{Cite journal |last=Gibbard |first=Philip L. |last2=Bauer |first2=Andrew M. |last3=Edgeworth |first3=Matthew |last4=Ruddiman |first4=William F. |last5=Gill |first5=Jacquelyn L. |last6=Merritts |first6=Dorothy J. |last7=Finney |first7=Stanley C. |last8=Edwards |first8=Lucy E. |last9=Walker |first9=Michael J. C. |last10=Maslin |first10=Mark |last11=Ellis |first11=Erle C. |date=2021-11-15 |title=A practical solution: the Anthropocene is a geological event, not a formal epoch |url=http://www.episodes.org/journal/view.html?doi=10.18814/epiiugs/2021/021029 |journal=Episodes |language=en |doi=10.18814/epiiugs/2021/021029 |issn=0705-3797}}</ref><ref name="Head_2021">{{Cite journal |last=Head |first=Martin J. |last2=Steffen |first2=Will |last3=Fagerlind |first3=David |last4=Waters |first4=Colin N. |last5=Poirier |first5=Clement |last6=Syvitski |first6=Jaia |last7=Zalasiewicz |first7=Jan A. |last8=Barnosky |first8=Anthony D. |last9=Cearreta |first9=Alejandro |last10=Jeandel |first10=Catherine |last11=Leinfelder |first11=Reinhold |date=2021-11-15 |title=The Great Acceleration is real and provides a quantitative basis for the proposed Anthropocene Series/Epoch |url=http://www.episodes.org/journal/view.html?doi=10.18814/epiiugs/2021/021031 |journal=Episodes |language=en |doi=10.18814/epiiugs/2021/021031 |issn=0705-3797}}</ref><ref name="Zalasiewicz_2021">{{Cite journal |last=Zalasiewicz |first=Jan |last2=Waters |first2=Colin N. |last3=Ellis |first3=Erle C. |last4=Head |first4=Martin J. |last5=Vidas |first5=Davor |last6=Steffen |first6=Will |last7=Thomas |first7=Julia Adeney |last8=Horn |first8=Eva |last9=Summerhayes |first9=Colin P. |last10=Leinfelder |first10=Reinhold |last11=McNeill |first11=J. R. |date=2021 |title=The Anthropocene: Comparing Its Meaning in Geology (Chronostratigraphy) with Conceptual Approaches Arising in Other Disciplines |url=https://onlinelibrary.wiley.com/doi/10.1029/2020EF001896 |journal=Earth's Future |language=en |volume=9 |issue=3 |doi=10.1029/2020EF001896 |issn=2328-4277}}</ref><ref name="Bauer_2021">{{Cite journal |last=Bauer |first=Andrew M. |last2=Edgeworth |first2=Matthew |last3=Edwards |first3=Lucy E. |last4=Ellis |first4=Erle C. |last5=Gibbard |first5=Philip |last6=Merritts |first6=Dorothy J. |date=2021-09-16 |title=Anthropocene: event or epoch? |url=https://www.nature.com/articles/d41586-021-02448-z |journal=Nature |language=en |volume=597 |issue=7876 |pages=332–332 |doi=10.1038/d41586-021-02448-z |issn=0028-0836}}</ref> |
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[[File:Geological time spiral.png|thumb|Graphical representation of Earth's history as a spiral]] |
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=== Proposals for revisions to pre-Cryogenian timeline === |
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===Early history=== |
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==== Shields et al. 2021 ==== |
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In [[Ancient Greece]], [[Aristotle]] (384–322 BCE) observed that [[fossil]]s of seashells in rocks resembled those found on beaches – he inferred that the fossils in rocks were formed by organisms, and he reasoned that the positions of land and sea had changed over long periods of time. [[Leonardo da Vinci]] (1452–1519) concurred with Aristotle's interpretation that fossils represented the remains of ancient life.<ref>{{cite web|url=http://www.wmnh.com/wmas0002.htm|title=Correlating Earth's History|first=Paul R.|last=Janke|publisher = Worldwide Museum of Natural History|date = 1999}}</ref> |
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An international working group of the ICS on pre-Cryogenian chronostratigraphic subdivision have outlined a template to improve the pre-Cyrogenian geologic time scale based on the rock record to bring it in line with the post-Tonian geologic time scale.<ref name="Shields_2022_pre-Cryogenian" /> This work assessed the geologic history of the currently defined eons and eras of the pre-Cambrian,{{Efn|name=Precam|group=note}} and the proposals in the "Geological Time Scale" books ''2004,''<ref name="GTS2004_Precambrian">{{Citation |last=Bleeker |first=W. |title=Toward a “natural” Precambrian time scale |date=2005-03-17 |url=https://www.cambridge.org/core/product/identifier/CBO9780511536045A067/type/book_part |work=A Geologic Time Scale 2004 |pages=141–146 |editor-last=Gradstein |editor-first=Felix M. |edition=1 |publisher=Cambridge University Press |doi=10.1017/cbo9780511536045.011 |isbn=978-0-521-78673-7 |access-date=2022-04-09 |editor2-last=Ogg |editor2-first=James G. |editor3-last=Smith |editor3-first=Alan G.}}</ref> ''2012,''<ref name="GTS2012_Precambrian" /> and ''2020.''<ref name="GTS2020_Precambrian">{{Citation |last=Strachan |first=R. |title=Precambrian (4.56–1 Ga) |date=2020 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780128243602000164 |work=Geologic Time Scale 2020 |pages=481–493 |publisher=Elsevier |language=en |doi=10.1016/b978-0-12-824360-2.00016-4 |isbn=978-0-12-824360-2 |access-date=2022-04-09 |last2=Murphy |first2=J.B. |last3=Darling |first3=J. |last4=Storey |first4=C. |last5=Shields |first5=G.}}</ref> Their recommend revisions<ref name="Shields_2022_pre-Cryogenian" /> of the pre-Cryogenian geologic time scale were (changes from the current scale [v2022/02] are italicised): |
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* Three divisions of the Archean instead of four by dropping Eoarchean, and revisions to their geochronometric definition, along with the repositioning of the Siderian into the latest Neoarchean, and a potential Kratian division in the Neoarchean. |
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** Archean (4000–<em>2450</em> Ma) |
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*** Paleoarchean (4000–<em>3500</em> Ma) |
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*** Mesoarchean (<em>3500–3000</em> Ma) |
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*** Neoarchean (<em>3500–2450</em> Ma) |
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**** <em>Kratian</em> (no fixed time given, prior to the Siderian) – from Greek word ''κράτος'' (krátos), meaning strength. |
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**** Siderian (?–<em>2450</em> Ma) – moved from Proterozoic to end of Archean, no start time given, base of Paleoproterozoic defines the end of the Siderian |
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* Refinement of geochronometric divisions of the Proterozoic, Paleoproterozoic, repositioning of the Statherian into the Mesoproterozoic, new Skourian period/system in the Paleoproterozoic, new Kleisian or Syndian period/system in the Neoproterozoic. |
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** Paleoproterozoic (<em>2450–1800</em> Ma) |
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*** <em>Skourian</em> (<em>2450</em>–2300 Ma) – from the Greek word σκουριά (''skouriá''), meaning 'rust'. |
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*** Rhyacian (2300–2050 Ma) |
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*** Orosirian (2050–1800 Ma) |
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** Mesoproterozoic (<em>1800</em>–1000 Ma) |
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*** <em>Statherian</em> (1800–1600 Ma) |
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*** Calymmian (1600–1400 Ma) |
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*** Ectasian (1400-1200 Ma) |
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*** Stenian (1200–1000 Ma) |
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** Neoproterozoic (1000–538.8 Ma){{Efn|Geochronometric date for the Ediacaran has been adjusted to reflect ICC v2022/02 as the formal definition for the base of the Cambrian has not changed.|name=EdiacaranDate|group=note}} |
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*** <em>Kleisian</em> or <em>Syndian</em> (<em>1000–800</em> Ma) – respectively from the Greek words κλείσιμο (''kleísimo'') meaning 'closure', and σύνδεση (''sýndesi'') meaning 'connection'. |
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*** Tonian (<em>800</em>–720 Ma) |
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*** Cryogenian (720–635 Ma) |
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*** Ediacaran (635–538.8 Ma) |
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Proposed pre-Cambrian timeline (Shield et al. 2021, ICS working group on pre-Cryogenian chronostratigraphy), shown to scale:{{Efn|Kratian time span is not given in the article. It lies within the Neoarchean, and prior to the Siderian. The position shown here is an arbitrary division.|name=kratian|group=note}} |
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<timeline> |
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ImageSize = width:1300 height:100 |
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PlotArea = left:80 right:20 bottom:20 top:5 |
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AlignBars = justify |
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Colors = |
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id:proterozoic value:rgb(0.968,0.207,0.388) |
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id:neoproterozoic value:rgb(0.996,0.701,0.258) |
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id:ediacaran value:rgb(0.996,0.85,0.415) |
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id:cryogenian value:rgb(0.996,0.8,0.36) |
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id:tonian value:rgb(0.996,0.75,0.305) |
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id:kleisian value:rgb(0.996,0.773,0.431) |
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id:mesoproterozoic value:rgb(0.996,0.705,0.384) |
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id:stenian value:rgb(0.996,0.85,0.604) |
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id:ectasian value:rgb(0.996,0.8,0.541) |
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id:calymmian value:rgb(0.996,0.75,0.478) |
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id:paleoproterozoic value:rgb(0.968,0.263,0.44) |
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id:skourian value:rgb(0.949,0.439,0.545) |
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id:statherian value:rgb(0.968,0.459,0.655) |
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id:orosirian value:rgb(0.968,0.408,0.596) |
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id:rhyacian value:rgb(0.968,0.357,0.537) |
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id:archean value:rgb(0.996,0.157,0.498) |
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id:neoarchean value:rgb(0.976,0.608,0.757) |
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id:mesoarchean value:rgb(0.968,0.408,0.662) |
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id:paleoarchean value:rgb(0.96,0.266,0.624) |
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id:hadean value:rgb(0.717,0,0.494) |
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id:black value:black |
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id:white value:white |
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Period = from:-4600 till:-538.8 |
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TimeAxis = orientation:horizontal |
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ScaleMajor = unit:year increment:500 start:-4500 |
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ScaleMinor = unit:year increment:100 start:-4500 |
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PlotData = |
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align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5) |
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bar:Eonothem/Eon |
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from: -2450 till: -538.8 text:Proterozoic color:proterozoic |
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from: -4000 till: -2450 text:Archean color:archean |
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from: start till: -4000 text:Hadean color:hadean |
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bar:Erathem/Era |
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from: -1000 till: -538.8 text:Neoproterozoic color:neoproterozoic |
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from: -1800 till: -1000 text:Mesoproterozoic color:mesoproterozoic |
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from: -2450 till: -1800 text:Paleoproterozoic color:paleoproterozoic |
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from: -3000 till: -2450 text:Neoarchean color:neoarchean |
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from: -3300 till: -3000 text:Mesoarchean color:mesoarchean |
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from: -4000 till: -3300 text:Paleoarchean color:paleoarchean |
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from: start till: -4000 color:white |
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bar:System/Period fontsize:7 |
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from: -635 till: -538.8 text:Ed. color:ediacaran |
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from: -720 till: -635 text:Cr. color:cryogenian |
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from: -800 till: -720 text:Tonian color:tonian |
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from: -1000 till: -800 text:?kleisian color:kleisian |
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from: -1200 till: -1000 text:Stenian color:stenian |
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from: -1400 till: -1200 text:Ectasian color:ectasian |
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from: -1600 till: -1400 text:Calymmian color:calymmian |
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from: -1800 till: -1600 text:Statherian color:statherian |
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from: -2050 till: -1800 text:Orosirian color:orosirian |
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from: -2300 till: -2050 text:Rhyacian color:rhyacian |
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from: -2450 till: -2300 text:?Skourian color:skourian |
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from: -2700 till: -2450 text:Siderian color:neoarchean |
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from: -3000 till: -2700 text:?Kratian color:neoarchean |
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from: start till: -3000 color:white |
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</timeline> |
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Current ICC pre-Cambrian timeline (v2022/02), shown to scale: |
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<timeline> |
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ImageSize = width:1300 height:100 |
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PlotArea = left:80 right:20 bottom:20 top:5 |
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AlignBars = justify |
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Colors = |
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id:proterozoic value:rgb(0.968,0.207,0.388) |
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id:neoproterozoic value:rgb(0.996,0.701,0.258) |
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id:ediacaran value:rgb(0.996,0.85,0.415) |
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id:cryogenian value:rgb(0.996,0.8,0.36) |
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id:tonian value:rgb(0.996,0.75,0.305) |
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id:mesoproterozoic value:rgb(0.996,0.705,0.384) |
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id:stenian value:rgb(0.996,0.85,0.604) |
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id:ectasian value:rgb(0.996,0.8,0.541) |
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id:calymmian value:rgb(0.996,0.75,0.478) |
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id:paleoproterozoic value:rgb(0.968,0.263,0.44) |
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id:statherian value:rgb(0.968,0.459,0.655) |
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id:orosirian value:rgb(0.968,0.408,0.596) |
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id:rhyacian value:rgb(0.968,0.357,0.537) |
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id:siderian value:rgb(0.968,0.306,0.478) |
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id:archean value:rgb(0.996,0.157,0.498) |
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id:neoarchean value:rgb(0.976,0.608,0.757) |
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id:mesoarchean value:rgb(0.968,0.408,0.662) |
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id:paleoarchean value:rgb(0.96,0.266,0.624) |
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id:eoarchean value:rgb(0.902,0.114,0.549) |
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id:hadean value:rgb(0.717,0,0.494) |
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id:black value:black |
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id:white value:white |
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Period = from:-4600 till:-538.8 |
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TimeAxis = orientation:horizontal |
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ScaleMajor = unit:year increment:500 start:-4500 |
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ScaleMinor = unit:year increment:100 start:-4500 |
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PlotData = |
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align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5) |
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bar:Eonothem/Eon |
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from: -2500 till: -538.8 text:Proterozoic color:proterozoic |
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from: -4000 till: -2500 text:Archean color:archean |
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from: start till: -4000 text:Hadean color:hadean |
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bar:Erathem/Era |
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from: -1000 till: -538.8 text:Neoproterozoic color:neoproterozoic |
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from: -1600 till: -1000 text:Mesoproterozoic color:mesoproterozoic |
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from: -2500 till: -1600 text:Paleoproterozoic color:paleoproterozoic |
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from: -2800 till: -2500 text:Neoarchean color:neoarchean |
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from: -3200 till: -2800 text:Mesoarchean color:mesoarchean |
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from: -3600 till: -3200 text:Paleoarchean color:paleoarchean |
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from: -4000 till: -3600 text:Eoarchean color:eoarchean |
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from: start till: -4000 color:white |
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bar:Sytem/Period fontsize:7 |
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from: -635 till: -538.8 text:Ed. color:ediacaran |
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from: -720 till: -635 text:Cr. color:cryogenian |
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from: -1000 till: -720 text:Tonian color:tonian |
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from: -1200 till: -1000 text:Stenian color:stenian |
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from: -1400 till: -1200 text:Ectasian color:ectasian |
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from: -1600 till: -1400 text:Calymmian color:calymmian |
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from: -1800 till: -1600 text:Statherian color:statherian |
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from: -2050 till: -1800 text:Orosirian color:orosirian |
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from: -2300 till: -2050 text:Rhyacian color:rhyacian |
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from: -2500 till: -2300 text:Siderian color:siderian |
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from: start till: -2500 color:white |
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</timeline> |
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==== Van Kranendonk et al. 2012 (GTS2012) ==== |
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The 11th-century [[Islamic geography|Persian polymath]] [[Avicenna]] (Ibn Sina, died 1037) and the 13th-century [[Dominican Order|Dominican]] [[bishop]] [[Albertus Magnus]] (died 1280) extended Aristotle's explanation into a theory of a [[petrification|petrifying]] fluid.<ref>{{Cite book|title= The Meaning of Fossils: Episodes in the History of Palaeontology|first= M. J. S.|last= Rudwick|date= 1985|publisher= [[University of Chicago Press]]|isbn= 978-0-226-73103-2|page= 24}}</ref> Avicenna also first proposed one of the principles underlying geologic time scales, the [[law of superposition]] of strata, while discussing the origins of mountains in ''[[The Book of Healing]]'' (1027).<ref>{{Cite journal|doi= 10.1111/j.1365-3091.2008.01009.x|title= The role of the Mediterranean region in the development of sedimentary geology: A historical overview|date= 2009|last1= Fischer|first1= Alfred G.|last2= Garrison|first2= Robert E.|journal= Sedimentology|volume= 56|issue= 1|pages= 3|bibcode = 2009Sedim..56....3F |s2cid= 128604255}}</ref> The [[History of science and technology in China|Chinese naturalist]] [[Shen Kuo]] (1031–1095) also recognized the concept of "[[deep time]]".<ref name="Silvin"> |
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The book, ''Geologic Time Scale 2012,'' was the last commercial publication of an international chronostratigraphic chart that was closely associated with the ICS.<ref name="ICC_Cohen_2013" /> It included a proposal to substantially revise the pre-Cryogenian time scale to reflect important events such as the [[Formation and evolution of the Solar System|formation of the solar system]] and the [[Great Oxidation Event]], among others, while at the same time maintaining most of the previous chronostratigraphic nomenclature for the pertinent time span.<ref name="GTS2012">{{cite book |last=Van Kranendonk |first=Martin J. |title=The geologic time scale 2012 |date=2012 |publisher=Elsevier |isbn=978-0-44-459425-9 |editor=Felix M. Gradstein |edition=1st |location=Amsterdam |pages=359–365 |chapter=16: A Chronostratigraphic Division of the Precambrian: Possibilities and Challenges |doi=10.1016/B978-0-444-59425-9.00016-0 |editor2=James G. Ogg |editor3=Mark D. Schmitz |editor4=abi M. Ogg}}</ref> {{As of|2022|April}} these proposed changes have not been accepted by the ICS. The proposed changes were (changes from the current scale [v2022/02] are italicised): |
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{{Cite book |
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| last = Sivin | first = Nathan |
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| author-link = Nathan Sivin |
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| title = Science in Ancient China: Researches and Reflections |
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| publisher = Ashgate Publishing [[Variorum]] series |
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| date = 1995 | location = [[Brookfield, Vermont|Brookfield]], Vermont |
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| pages = III, 23–24 | no-pp = true |
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}} |
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</ref> |
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* Hadean Eon (<em>4567–4030</em> Ma) |
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===Establishment of primary principles=== |
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** [[Chaotian (geology)|Chaotian]] Era/Erathem (4567–4404 Ma) – the name alluding both to the [[Chaos (cosmogony)|mythological Chaos]] and the [[Chaos theory|chaotic]] phase of [[planet formation]].<ref name="GTS2012" /><ref name="Goldblatt_2010">{{cite journal |last1=Goldblatt |first1=C. |last2=Zahnle |first2=K. J. |last3=Sleep |first3=N. H. |last4=Nisbet |first4=E. G. |date=2010 |title=The Eons of Chaos and Hades |journal=Solid Earth |volume=1 |issue=1 |pages=1–3 |bibcode=2010SolE....1....1G |doi=10.5194/se-1-1-2010 |doi-access=free}}</ref><ref>{{cite journal |last=Chambers |first=John E. |date=July 2004 |title=Planetary accretion in the inner Solar System |url=http://www.astro.washington.edu/courses/astro321/Chambers_EPSL_04.pdf |journal=Earth and Planetary Science Letters |volume=223 |issue=3–4 |pages=241–252 |bibcode=2004E&PSL.223..241C |doi=10.1016/j.epsl.2004.04.031}}</ref> |
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In the late 17th century [[Nicolas Steno]] (1638–1686) pronounced the principles underlying geologic (geological) time scales. Steno argued that rock layers (or strata) were laid down in succession and that each represents a "slice" of time. He also formulated the law of superposition, which states that any given stratum is probably older than those above it and younger than those below it. While Steno's principles were simple, applying them proved challenging. Steno's ideas also lead to other important concepts geologists use today, such as [[relative dating]]. Over the course of the 18th-century geologists realized that: |
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** <em>Jack Hillsian</em> or <em>Zirconian</em> Era/Erathem (<em>4404–4030</em> Ma) – both names allude to the Jack Hills Greenstone Belt which provided the oldest mineral grains on Earth, [[Zircon|zircons]].<ref name="GTS2012" /><ref name="Goldblatt_2010" /> |
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* Archean Eon/Eonothem (<em>4030–2420</em> Ma) |
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** Paleoarchean Era/Erathem (<em>4030–3490</em> Ma) |
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*** <em>Acastan</em> Period/System (<em>4030–3810</em> Ma) – named after the [[Acasta Gneiss]], one of the oldest preserved pieces of [[continental crust]].<ref name="GTS2012" /><ref name="Goldblatt_2010" /> |
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*** <em>Isuan</em> Period (3<em>810–3490</em> Ma) – named after the [[Isua Greenstone Belt]].<ref name="GTS2012" /> |
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** Mesoarchean Era/Erathem (<em>3490–2780</em> Ma) |
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*** <em>Vaalbaran</em> Period/System (<em>3490–3020</em> Ma) – based on the names of the [[Kapvaal craton|Kapvaal]] (Southern Africa) and [[Pilbara Craton|Pilbara]] (Western Australia) [[Craton|cratons,]] to reflect the growth of stable continental nuclei or proto-[[Craton|cratonic]] kernels.<ref name="GTS2012" /> |
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*** <em>Pongolan</em> Period/System (<em>3020–2780</em> Ma) – named after the Pongola Supergroup, in reference to the well preserved evidence of terrestrial microbial communities in those rocks.<ref name="GTS2012" /> |
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** Neoarchean Era/Erathem (<em>2780–2420</em> Ma) |
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*** <em>Methanian</em> Period/System (<em>2780–2630</em> Ma) – named for the inferred predominance of [[methanotrophic]] [[prokaryotes]]<ref name="GTS2012" /> |
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*** Siderian Period/System (<em>2630–2420</em> Ma) – named for the voluminous [[Banded iron formation|banded iron formations]] formed within its duration.<ref name="GTS2012" /> |
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* Proterozoic Eon/Eonothem (<em>2420</em>–538.8 Ma){{efn|name=EdiacaranDate|group=note}} |
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** Paleoproterozoic Era/Erathem (<em>2420–1780</em> Ma) |
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*** <em>Oxygenian</em> Period/System (<em>2420–2250</em> Ma) – named for displaying the first evidence for a global oxidizing atmosphere.<ref name="GTS2012" /> |
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*** <em>Jatulian</em> or <em>Eukaryian</em> Period/System (<em>2250–2060</em> Ma) – names are respectively for the Lomagundi–Jatuli δ<sup>13</sup>C isotopic excursion event spanning its duration, and for the (proposed)<ref name="El_Albani_2014">{{cite journal |last1=El Albani |first1=Abderrazak |last2=Bengtson |first2=Stefan |last3=Canfield |first3=Donald E. |last4=Riboulleau |first4=Armelle |last5=Rollion Bard |first5=Claire |last6=Macchiarelli |first6=Roberto |display-authors=etal |year=2014 |title=The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity |journal=PLOS ONE |volume=9 |issue=6 |pages=e99438 |bibcode=2014PLoSO...999438E |doi=10.1371/journal.pone.0099438 |pmc=4070892 |pmid=24963687 |doi-access=free}}</ref><ref name="El_Albani_2010">{{cite journal |last1=El Albani |first1=Abderrazak |last2=Bengtson |first2=Stefan |last3=Canfield |first3=Donald E. |last4=Bekker |first4=Andrey |last5=Macchiarelli |first5=Roberto |last6=Mazurier |first6=Arnaud |last7=Hammarlund |first7=Emma U. |display-authors=etal |year=2010 |title=Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago |url=http://www.afrikibouge.com/publications/Article%20Albani.pdf |journal=Nature |volume=466 |issue=7302 |pages=100–104 |bibcode=2010Natur.466..100A |doi=10.1038/nature09166 |pmid=20596019 |s2cid=4331375}}{{Dead link|date=February 2022|bot=InternetArchiveBot|fix-attempted=yes}}</ref> first fossil appearance of [[Eukaryota|eukaryotes]].<ref name="GTS2012" /> |
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*** <em>Columbian Period/System</em> (<em>2060–1780</em> Ma) – named after the [[supercontinent]] [[Columbia (supercontinent)|Columbia]].<ref name="GTS2012" /> |
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** Mesoproterozoic Era/Erathem (<em>1780–850</em> Ma) |
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*** <em>Rodinian</em> Period/System (<em>1780–850</em> Ma) – named after the supercontinent [[Rodinia]], stable environment.<ref name="GTS2012" /> |
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Proposed pre-Cambrian timeline (GTS2012), shown to scale: |
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# Sequences of strata often become eroded, distorted, tilted, or even inverted after deposition |
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<timeline> |
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# Strata laid down at the same time in different areas could have entirely different appearances |
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ImageSize = width:1200 height:100 |
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# The strata of any given area represented only part of Earth's long history |
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PlotArea = left:80 right:20 bottom:20 top:5 |
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The [[Neptunist]] theories popular at this time (expounded by [[Abraham Gottlob Werner|Abraham Werner]] (1749–1817) in the late 18th century) proposed that all rocks had precipitated out of a single enormous flood. A major shift in thinking came when [[James Hutton]] presented his ''Theory of the Earth; or, an Investigation of the Laws Observable in the Composition, Dissolution, and Restoration of Land Upon the Globe''<ref> |
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AlignBars = justify |
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{{cite journal |
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Colors = |
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| last1 = Hutton |
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id:proterozoic value:rgb(0.968,0.207,0.388) |
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| first1 = James |
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id:neoproterozoic value:rgb(0.996,0.701,0.258) |
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| author-link1 = James Hutton |
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id:ediacaran value:rgb(0.996,0.85,0.415) |
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| title = Theory of the Earth; or an investigation of the laws observable in the composition, dissolution, and restoration of land upon the Globe |
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id:cryogenian value:rgb(0.996,0.8,0.36) |
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| url = https://archive.org/stream/cbarchive_106252_theoryoftheearthoraninvestigat1788/theoryoftheearthoraninvestigat1788#page/n1/mode/2up |
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id:tonian value:rgb(0.996,0.75,0.305) |
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| journal = Transactions of the Royal Society of Edinburgh |
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id:mesoproterozoic value:rgb(0.996,0.705,0.384) |
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| publication-date = 1788 |
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id:rodinian value:rgb(0.996,0.75,0.478) |
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| volume = 1 |
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id:paleoproterozoic value:rgb(0.968,0.263,0.44) |
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| issue = 2 |
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id:columbian value:rgb(0.968,0.459,0.655) |
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| pages = 209–308 |
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id:eukaryian value:rgb(0.968,0.408,0.596) |
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| access-date = 2016-09-06 |
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id:oxygenian value:rgb(0.968,0.357,0.537) |
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| doi=10.1017/s0080456800029227 |
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id:archean value:rgb(0.996,0.157,0.498) |
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| year = 2013 |
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id:neoarchean value:rgb(0.976,0.608,0.757) |
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}} |
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id:siderian value:rgb(0.976,0.7,0.85) |
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</ref> |
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id:methanian value:rgb(0.976,0.65,0.8) |
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before the [[Royal Society of Edinburgh]] in March and April 1785. [[John McPhee]] asserts that "as things appear from the perspective of the 20th century, James Hutton in those readings became the founder of modern geology".<ref name="mcphee"> |
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id:mesoarchean value:rgb(0.968,0.408,0.662) |
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{{cite book|first=John|last=McPhee|author-link=John McPhee|title=Basin and Range|location=New York|publisher=Farrar, Straus and Giroux|date=1981|isbn = 9780374109141}}</ref>{{rp|95–100}} Hutton proposed that the interior of Earth was hot and that this heat was the engine which drove the creation of new rock: land was eroded by air and water and deposited as layers in the sea; heat then consolidated the sediment into stone and uplifted it into new lands. This theory, known as "[[Plutonism]]", stood in contrast to the "Neptunist" flood-oriented theory. |
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id:pongolan value:rgb(0.968,0.5,0.75) |
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id:vaalbaran value:rgb(0.968,0.45,0.7) |
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id:paleoarchean value:rgb(0.96,0.266,0.624) |
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id:isuan value:rgb(0.96,0.35,0.65) |
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id:acastan value:rgb(0.96,0.3,0.6) |
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id:hadean value:rgb(0.717,0,0.494) |
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id:zirconian value:rgb(0.902,0.114,0.549) |
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id:chaotian value:rgb(0.8,0.05,0.5) |
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id:black value:black |
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id:white value:white |
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Period = from:-4600 till:-538.8 |
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TimeAxis = orientation:horizontal |
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ScaleMajor = unit:year increment:500 start:-4500 |
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ScaleMinor = unit:year increment:100 start:-4500 |
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PlotData = |
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align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5) |
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bar:Eonothem/Eon |
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from: -2420 till: -538.8 text:Proterozoic color:proterozoic |
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from: -4030 till: -2420 text:Archean color:archean |
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from: -4567 till: -4030 text:Hadean color:hadean |
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from: start till: -4567 color:white |
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bar:Erathem/Era |
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from: -850 till: -538.8 text:Neoproterozoic color:neoproterozoic |
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from: -1780 till: -850 text:Mesoproterozoic color:mesoproterozoic |
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from: -2420 till: -1780 text:Paleoproterozoic color:paleoproterozoic |
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from: -2780 till: -2420 text:Neoarchean color:neoarchean |
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from: -3490 till: -2780 text:Mesoarchean color:mesoarchean |
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from: -4030 till: -3490 text:Paleoarchean color:paleoarchean |
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from: -4404 till: -4030 text:Zirconian color:zirconian |
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from: -4567 till: -4404 text:Chaotian color:chaotian |
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from: start till: -4567 color:white |
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bar:System/Period fontsize:7 |
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from: -630 till: -538.8 text:Ed. color:ediacaran |
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from: -850 till: -630 text:Cr. color:cryogenian |
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from: -1780 till: -850 text:Rodinian color:rodinian |
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from: -2060 till: -1780 text:Columbian color:columbian |
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from: -2250 till: -2060 text:Eukaryian color:eukaryian |
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from: -2420 till: -2250 text:Oxygenian color:oxygenian |
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from: -2630 till: -2420 text:Siderian color:siderian |
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from: -2780 till: -2630 text:Methanian color:methanian |
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from: -3020 till: -2780 text:Pongolan color:pongolan |
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from: -3490 till: -3020 text:Vaalbaran color:vaalbaran |
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from: -3810 till: -3490 text:Isuan color:isuan |
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from: -4030 till: -3810 text:Acastan color:acastan |
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from: start till: -4030 color:white |
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</timeline> |
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Current ICC pre-Cambrian timeline (v2022/02), shown to scale: |
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===Formulation of geologic time scale=== |
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<timeline> |
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The first serious attempts to formulate a geologic time scale that could be applied anywhere on Earth were made in the late 18th century. The most influential of those early attempts (championed by [[Abraham Gottlob Werner|Werner]], among others) divided the rocks of Earth's crust into four types: Primary, Secondary, Tertiary, and Quaternary. Each type of rock, according to the theory, formed during a specific period in Earth history. It was thus possible to speak of a "Tertiary Period" as well as of "Tertiary Rocks." Indeed, "Tertiary" (now Paleogene and Neogene) remained in use as the name of a geological period well into the 20th century and "Quaternary" remains in formal use as the name of the current period. |
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ImageSize = width:1200 height:100 |
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PlotArea = left:80 right:20 bottom:20 top:5 |
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The identification of strata by the fossils they contained, pioneered by [[William Smith (geologist)|William Smith]], [[Georges Cuvier]], [[Jean Baptiste Julien d'Omalius d'Halloy|Jean d'Omalius d'Halloy]], and [[Alexandre Brongniart]] in the early 19th century, enabled geologists to divide Earth history more precisely. It also enabled them to correlate strata across national (or even continental) boundaries. If two strata (however distant in space or different in composition) contained the same fossils, chances were good that they had been laid down at the same time. Detailed studies between 1820 and 1850 of the strata and fossils of Europe produced the sequence of geologic periods still used today. |
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AlignBars = justify |
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Colors = |
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===Naming of geologic periods, eras and epochs=== |
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id:proterozoic value:rgb(0.968,0.207,0.388) |
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Early work on developing the geologic time scale was dominated by British geologists, and the names of the geologic periods reflect that dominance. The "Cambrian", (the classical name for [[Wales]]) and the "Ordovician" and "Silurian", named after ancient Welsh tribes, were periods defined using stratigraphic sequences from Wales.<ref name="mcphee"/>{{rp|113–114}} The "Devonian" was named for the English county of [[Devon]], and the name "Carboniferous" was an adaptation of "the Coal Measures", the old British geologists' term for the same set of strata. The "Permian" was named after the [[Great Perm|region of Perm]] in Russia, because it was defined using strata in that region by Scottish geologist [[Roderick Murchison]]. However, some periods were defined by geologists from other countries. The "Triassic" was named in 1834 by a German geologist [[Friedrich Von Alberti]] from the three distinct layers (Latin {{lang|la|trias}} meaning triad){{snd}}[[red bed]]s, capped by [[chalk]], followed by black [[shale]]s{{snd}}that are found throughout Germany and Northwest Europe, called the ‘Trias’. The "Jurassic" was named by a French geologist [[Alexandre Brongniart]] for the extensive marine [[limestone]] exposures of the [[Jura Mountains]]. The "Cretaceous" (from Latin ''creta'' meaning ‘[[chalk]]’) as a separate period was first defined by Belgian geologist [[Jean Baptiste Julien d'Omalius d'Halloy|Jean d'Omalius d'Halloy]] in 1822, using strata in the [[Paris basin]]<ref>{{Cite encyclopedia |title=Great Soviet Encyclopedia|publisher=Sovetskaya Enciklopediya|edition=3rd|pages=vol. 16, p. 50|date=1974|location=Moscow|language=ru|no-pp=true|title-link=Great Soviet Encyclopedia}}</ref> and named for the extensive beds of chalk ([[calcium carbonate]] deposited by the shells of marine [[invertebrate]]s) found in Western Europe. |
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id:neoproterozoic value:rgb(0.996,0.701,0.258) |
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id:ediacaran value:rgb(0.996,0.85,0.415) |
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British geologists were also responsible for the grouping of periods into eras and the subdivision of the Tertiary and Quaternary periods into epochs. In 1841 [[John Phillips (geologist)|John Phillips]] published the first global geologic time scale based on the types of fossils found in each era. Phillips' scale helped standardize the use of terms like ''[[Paleozoic]]'' ("old life"), which he extended to cover a larger period than it had in previous usage, and ''[[Mesozoic]]'' ("middle life"), which he invented.<ref>{{cite book|last=Rudwick|first=Martin|title=Worlds Before Adam: The Reconstruction of Geohistory in the Age of Reform|date=2008|pages= 539–545}}</ref> |
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id:cryogenian value:rgb(0.996,0.8,0.36) |
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id:tonian value:rgb(0.996,0.75,0.305) |
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===Dating of time scales=== |
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id:mesoproterozoic value:rgb(0.996,0.705,0.384) |
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{{Main|Chronological dating}} |
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id:stenian value:rgb(0.996,0.85,0.604) |
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id:ectasian value:rgb(0.996,0.8,0.541) |
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When William Smith and [[Sir Charles Lyell]] first recognized that rock strata represented successive time periods, time scales could be estimated only very imprecisely since estimates of rates of change were uncertain. While [[Creationism|creationists]] had been proposing dates of around six or seven thousand years for the age of Earth based on the [[Bible]], early geologists were suggesting millions of years for geologic periods, and some were even suggesting a virtually infinite age for Earth.{{citation needed|date=September 2017}} Geologists and paleontologists constructed the geologic table based on the relative positions of different strata and fossils, and estimated the time scales based on studying rates of various kinds of [[weathering]], [[erosion]], [[sedimentation]], and [[lithification]]. Until the discovery of [[Radioactive decay|radioactivity]] in 1896 and the development of its geological applications through [[radiometric dating]] during the first half of the 20th century, the ages of various rock strata and the age of Earth were the subject of considerable debate. |
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id:calymmian value:rgb(0.996,0.75,0.478) |
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id:paleoproterozoic value:rgb(0.968,0.263,0.44) |
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The first geologic time scale that included absolute dates was published in 1913 by the British geologist [[Arthur Holmes]].<ref>{{cite web|url=http://www.enchantedlearning.com/subjects/Geologictime.html|title=Geologic Time Scale|publisher = EnchantedLearning.com}}</ref> He greatly furthered the newly created discipline of [[geochronology]] and published the world-renowned book ''The Age of the Earth'' in which he estimated Earth's age to be at least 1.6 billion years.<ref>{{cite web|url=http://www.bris.ac.uk/news/2007/5609.html|title=How the discovery of geologic time changed our view of the world|publisher=Bristol University}}</ref> |
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id:statherian value:rgb(0.968,0.459,0.655) |
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id:orosirian value:rgb(0.968,0.408,0.596) |
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In a steady effort ongoing since 1974, the [[International Commission on Stratigraphy]] has been working to correlate the world's local [[stratigraphy|stratigraphic record]] into one uniform planet-wide benchmarked system.<ref>{{cite journal|last1=Martinsson |first1=Anders |last2=Bassett|first2=Michael G. |title=International Commission on Stratigraphy |journal=Lethaia |volume=13 |number=1 |year=1980|page=26 |doi=10.1111/j.1502-3931.1980.tb01026.x }}</ref> |
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id:rhyacian value:rgb(0.968,0.357,0.537) |
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id:siderian value:rgb(0.968,0.306,0.478) |
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In 1977, the ''Global Commission on Stratigraphy'' (now the [[International Commission on Stratigraphy]]) began to define global references known as GSSP ([[Global Boundary Stratotype Section and Point|Global Boundary Stratotype Sections and Points]]) for geologic periods and faunal stages. The commission's work is described in the 2012 geologic time scale of Gradstein et al.<ref name="The Geologic Time Scale"/> A [[Unified Modeling Language|UML]] model for how the timescale is structured, relating it to the GSSP, is also available.<ref>{{cite journal |last1= Cox |first1= Simon J. D.|last2= Richard|first2= Stephen M.|date= 2005|title=A formal model for the geologic time scale and global stratotype section and point, compatible with geospatial information transfer standards |journal= Geosphere|volume= 1|issue= 3|pages= 119–137|doi= 10.1130/GES00022.1 |url= http://geosphere.geoscienceworld.org/content/1/3/119.full|access-date=31 December 2012|bibcode = 2005Geosp...1..119C |doi-access= free}}</ref> |
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id:archean value:rgb(0.996,0.157,0.498) |
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id:neoarchean value:rgb(0.976,0.608,0.757) |
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===Correlation issues=== |
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id:mesoarchean value:rgb(0.968,0.408,0.662) |
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American geologists have long considered the [[Mississippian age|Mississippian]] and [[Pennsylvanian (geology)|Pennsylvanian]] to be periods in their own right though the ICS now recognises them both as "subperiods" of the [[Carboniferous]] Period recognised by European geologists.<ref name=":0">{{Citation|last1=Davydov|first1=V.I.|title=The Carboniferous Period|date=2012|url=https://linkinghub.elsevier.com/retrieve/pii/B9780444594259000238|work=The Geologic Time Scale|pages=603–651|publisher=Elsevier|language=en|doi=10.1016/b978-0-444-59425-9.00023-8|isbn=978-0-444-59425-9|access-date=2021-06-17|last2=Korn|first2=D.|last3=Schmitz|first3=M.D.|last4=Gradstein|first4=F.M.|last5=Hammer|first5=O.}}</ref> Cases like this in China, Russia and even New Zealand with other geological eras has slowed the uniform organization of the stratigraphic record.<ref>{{cite journal |last1=Lucas |first1=Spencer G. |title=The GSSP Method of Chronostratigraphy: A Critical Review |journal=Frontiers in Earth Science |date=6 November 2018 |volume=6 |pages=191 |doi=10.3389/feart.2018.00191|bibcode=2018FrEaS...6..191L |doi-access=free }}</ref> |
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id:paleoarchean value:rgb(0.96,0.266,0.624) |
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id:eoarchean value:rgb(0.902,0.114,0.549) |
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===The Anthropocene=== |
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id:hadean value:rgb(0.717,0,0.494) |
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Popular culture and a growing number of scientists use the term "[[Anthropocene]]" informally to label the current epoch in which we are living.<ref>{{Cite web|last=Stromberg|first=Joseph|title=What Is the Anthropocene and Are We in It?|url=https://www.smithsonianmag.com/science-nature/what-is-the-anthropocene-and-are-we-in-it-164801414/|access-date=2021-01-15|website=Smithsonian Magazine|language=en}}</ref> The term was coined by [[Paul J. Crutzen|Paul Crutzen]] and [[Eugene F. Stoermer|Eugene Stoermer]] in 2000 to describe the current time in which humans have had an enormous impact on the environment. It has evolved to describe an "epoch" starting some time in the past and on the whole defined by anthropogenic carbon emissions and production and consumption of plastic goods that are left in the ground.<ref>{{Cite web|title = Anthropocene: Age of Man – Pictures, More From National Geographic Magazine|url = http://ngm.nationalgeographic.com/2011/03/age-of-man/kolbert-text/2|website = ngm.nationalgeographic.com|access-date = 2015-09-22|archive-date = 22 August 2016|archive-url = https://web.archive.org/web/20160822063850/http://ngm.nationalgeographic.com/2011/03/age-of-man/kolbert-text/2|url-status = dead}}</ref> |
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id:black value:black |
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id:white value:white |
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Critics of this term say that the term should not be used because it is difficult, if not nearly impossible, to define a specific time when humans started influencing the rock strata{{snd}}defining the start of an epoch.<ref>{{Cite web|title = What is the Anthropocene and Are We in It?|url = http://www.smithsonianmag.com/science-nature/what-is-the-anthropocene-and-are-we-in-it-164801414/?no-ist|access-date = 2015-09-22|first = Joseph|last = Stromberg}}</ref> |
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Period = from:-4600 till:-538.8 |
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TimeAxis = orientation:horizontal |
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The ICS has not officially approved the term {{As of|2015|9|lc=y}}.<ref name="icsanthropocene">{{Cite web |website= Subcommission on Quaternary Stratigraphy |title= Working Group on the 'Anthropocene'|url = http://quaternary.stratigraphy.org/workinggroups/anthropocene/|publisher= [[International Commission on Stratigraphy]]}}</ref> The Anthropocene Working Group met in Oslo in April 2016 to consolidate evidence supporting the argument for the Anthropocene as a true geologic epoch.<ref name = icsanthropocene/> Evidence was evaluated and the group voted to recommend "Anthropocene" as the new geological age in August 2016.<ref>{{Cite web|url=https://www.theguardian.com/environment/2016/aug/29/declare-anthropocene-epoch-experts-urge-geological-congress-human-impact-earth|title=The Anthropocene epoch: scientists declare dawn of human-influenced age|website=[[TheGuardian.com]]|date=29 August 2016}}</ref> |
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ScaleMajor = unit:year increment:500 start:-4500 |
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Should the International Commission on Stratigraphy approve the recommendation, the proposal to adopt the term will have to be ratified by the International Union of Geological Sciences before its formal adoption as part of the geologic time scale.<ref name="Gixmodo001"> |
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ScaleMinor = unit:year increment:100 start:-4500 |
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{{cite web |
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PlotData = |
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|author= George Dvorsky |
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align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5) |
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|url= https://gizmodo.com/new-evidence-suggests-human-beings-are-a-geological-for-1751429480 |
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bar:Eonothem/Eon |
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|title= New Evidence Suggests Human Beings Are a Geological Force of Nature |
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from: -2500 till: -538.8 text:Proterozoic color:proterozoic |
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|date= 7 January 2016 |
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from: -4000 till: -2500 text:Archean color:archean |
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|publisher= Gizmodo.com |access-date= 2016-10-15 |
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from: start till: -4000 text:Hadean color:hadean |
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}} |
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bar:Erathem/Era |
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</ref> |
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from: -1000 till: -538.8 text:Neoproterozoic color:neoproterozoic |
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from: -1600 till: -1000 text:Mesoproterozoic color:mesoproterozoic |
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===Notable period changes=== |
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from: -2500 till: -1600 text:Paleoproterozoic color:paleoproterozoic |
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* Changes in recent years have included the abandonment of the former [[Tertiary]] Period in favour of the [[Paleogene]] and succeeding [[Neogene]] periods. This remains controversial.<ref>{{cite journal |last1=Knox |first1=R.W.O’B. |last2=Pearson |first2=P.N. |last3=Barry |first3=T.L. |last4=Condon |first4=D.J. |last5=Cope |first5=J.C.W. |last6=Gale |first6=A.S. |last7=Gibbard |first7=P.L. |last8=Kerr |first8=A.C. |last9=Hounslow |first9=M.W. |last10=Powell |first10=J.H. |last11=Rawson |first11=P.F. |last12=Smith |first12=A.G. |last13=Waters |first13=C.N. |last14=Zalasiewicz |first14=J. |title=Examining the case for the use of the Tertiary as a formal period or informal unit |journal=Proceedings of the Geologists' Association |date=June 2012 |volume=123 |issue=3 |pages=390–393 |doi=10.1016/j.pgeola.2012.05.004}}</ref> |
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from: -2800 till: -2500 text:Neoarchean color:neoarchean |
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* The abandonment of the [[Quaternary]] period was also considered but it has been retained for continuity reasons.<ref>{{cite journal |last1=Gibbard |first1=Philip L. |last2=Smith |first2=Alan G. |last3=Zalasiewicz |first3=Jan A. |last4=Barry |first4=Tiffany L. |last5=Cantrill |first5=David |last6=Coe |first6=Angela L. |last7=Cope |first7=John C. W. |last8=Gale |first8=Andrew S. |last9=Gregory |first9=F. John |last10=Powell |first10=John H. |last11=Rawson |first11=Peter F. |last12=Stone |first12=Philip |last13=Waters |first13=Colin N. |title=What status for the Quaternary? |journal=Boreas |date=28 June 2008 |volume=34 |issue=1 |pages=1–6 |doi=10.1111/j.1502-3885.2005.tb01000.x|s2cid=130106969 }}</ref> |
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from: -3200 till: -2800 text:Mesoarchean color:mesoarchean |
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* Even earlier in the history of the science, the Tertiary was considered to be an "era" and its subdivisions ([[Paleocene]], [[Eocene]], [[Oligocene]], [[Miocene]] and [[Pliocene]]) were themselves referred to as "periods"<ref>See, for example, {{cite journal|jstor=24204747|title=Presidential Address: The Deccan Traps: An Episode of the Tertiary Era|last1=Sahni|first1=B.|journal=Current Science|year=1940|volume=9|issue=1|pages=47–54}}</ref> but they now enjoy the status of "epochs" within the more recently delineated [[Paleogene]] and [[Neogene]] periods.<ref name=ICS/> |
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from: -3600 till: -3200 text:Paleoarchean color:paleoarchean |
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from: -4000 till: -3600 text:Eoarchean color:eoarchean |
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from: start till: -4000 color:white |
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bar:System/Period fontsize:7 |
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from: -635 till: -538.8 text:Ed. color:ediacaran |
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from: -720 till: -635 text:Cr. color:cryogenian |
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from: -1000 till: -720 text:Tonian color:tonian |
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from: -1200 till: -1000 text:Stenian color:stenian |
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from: -1400 till: -1200 text:Ectasian color:ectasian |
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from: -1600 till: -1400 text:Calymmian color:calymmian |
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from: -1800 till: -1600 text:Statherian color:statherian |
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from: -2050 till: -1800 text:Orosirian color:orosirian |
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from: -2300 till: -2050 text:Rhyacian color:rhyacian |
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from: -2500 till: -2300 text:Siderian color:siderian |
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from: start till: -2500 color:white |
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</timeline> |
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==Table of geologic time== |
==Table of geologic time== |
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The following table |
The following table summarises the major events and characteristics of the divisions making up the geologic time scale of Earth. This table is arranged with the most recent geologic periods at the top, and the oldest at the bottom. The height of each table entry does not correspond to the duration of each subdivision of time. As such, this table is not to scale and does not accurately represent the relative time-spans of each geochronologic unit. While the [[Phanerozoic]] Eon looks longer than the rest, it merely spans ~539 million years (~12% of Earth's history), whilst the previous three eons{{Efn|name=Precam|group=note}} collectively span ~3,461 million years (~76% of Earth's history). This bias toward the most recent eon is in part due to the relative lack of information about events that occurred during the first three eons compared to the current eon (the Phanerozoic).<ref name="Shields_2022_pre-Cryogenian" /><ref>{{cite web |title=Geological time scale |url=https://www.digitalatlasofancientlife.org/learn/geological-time/geological-time-scale/ |access-date=January 17, 2022 |work=Digital Atlas of Ancient Life |publisher=Paleontological Research Institution}}</ref> The use of subseries/subepochs has been ratified by the ICS.<ref name ="Aubry_2022_subseries"/> |
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The content of the table is based on the official geologic time scale of the International Commission on Stratigraphy (ICS).<ref name=":1" /> The current version is provided by the ICS online.<ref>{{Cite web |title=Chart |url=https://stratigraphy.org/chart |access-date=2022-04-02 |website=stratigraphy.org |publisher=International Commission on Stratigraphy}}</ref> The ICS provides an online interactive version of this chart, [https://stratigraphy.org/timescale/ ics-chart], based on a service delivering a machine-readable [[Resource Description Framework]]/[[Web Ontology Language]] representation of the timescale, which is available through the [[Commission for the Management and Application of Geoscience Information]] [[GeoSciML]] project as a service<ref>{{cite web|url=http://resource.geosciml.org/classifier/ics/ischart/|access-date=2014-08-03|title=Geologic Timescale Elements in the International Chronostratigraphic Chart}}</ref> and at a [[SPARQL]] end-point.<ref>{{cite web|url=http://resource.geosciml.org/sparql/isc2014 |archive-url=https://archive.today/20140806164132/http://resource.geosciml.org/sparql/isc2014 |url-status=dead |archive-date=2014-08-06 |access-date=2014-08-03 |title=SPARQL endpoint for CGI timescale service |first=Simon J. D.|last=Cox }}</ref><ref>{{cite journal|title=A geologic timescale ontology and service|first1=Simon J. D.|last1=Cox |first2=Stephen M.|last2=Richard|doi=10.1007/s12145-014-0170-6|volume=8|journal=Earth Science Informatics|pages=5–19|year=2014|s2cid=42345393}}</ref> |
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The [[Chronostratigraphy|chronostratrigraphic]] epoch/subepoch names are altered to the early/late format from lower/upper of the equivalent [[Geochronology|geochronologic]] series/subseries as is recommended by the ICS.<ref name="ICS_Ch9" /> Subseries/subepochs for the [[Neogene]] have been ratified as of 13 October 2021.<ref>{{Cite web |title=The Neogene Subseries/Subepochs are Formal Chronostratigraphic Units |url=https://stratigraphy.org/news/137 |access-date=2022-04-02 |website=stratigraphy.org |publisher=International Commission on Stratigraphy}}</ref> |
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This table is not to scale, and even though the [[Phanerozoic]] eon looks longer than the rest, it merely spans 539 million years, whilst the previous three eons (or the [[Precambrian]] supereon) collectively span over 3.5 billion years. This bias toward the most recent eon is due to the relative lack of information about events that occurred during the first three eons (or supereon) compared to the current eon (the Phanerozoic).<ref>{{cite web|url=https://www.digitalatlasofancientlife.org/learn/geological-time/geological-time-scale/ |title=Geological time scale |work=Digital Atlas of Ancient Life |publisher=Paleontological Research Institution |access-date=January 17, 2022}}</ref><ref>{{Cite journal |last1=Shields |first1=Graham A. |last2=Strachan |first2=Robin A. |last3=Porter |first3=Susannah M. |last4=Halverson |first4=Galen P. |last5=Macdonald |first5=Francis A. |last6=Plumb |first6=Kenneth A. |last7=de Alvarenga |first7=Carlos J. |last8=Banerjee |first8=Dhiraj M. |last9=Bekker |first9=Andrey |last10=Bleeker |first10=Wouter |last11=Brasier |first11=Alexander |date=2022 |title=A template for an improved rock-based subdivision of the pre-Cryogenian timescale |url=http://jgs.lyellcollection.org/lookup/doi/10.1144/jgs2020-222 |journal=Journal of the Geological Society |language=en |volume=179 |issue=1 |pages=jgs2020–222 |doi=10.1144/jgs2020-222 |bibcode=2022JGSoc.179..222S |s2cid=236285974 |issn=0016-7649}}</ref> |
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The content of the table is based on the official ICC produced and maintained by the ICS who also provide an online interactive version of this chart. The interactive version is based on a service delivering a machine-readable [[Resource Description Framework]]/[[Web Ontology Language]] representation of the time scale, which is available through the [[Commission for the Management and Application of Geoscience Information]] [[GeoSciML]] project as a service<ref name="web_GTSelements">{{cite web |title=Geologic Timescale Elements in the International Chronostratigraphic Chart |url=http://resource.geosciml.org/classifier/ics/ischart/ |access-date=2014-08-03}}</ref> and at a [[SPARQL]] end-point.<ref name="web_Cox_SPARQL_GTS">{{cite web |last=Cox |first=Simon J. D. |title=SPARQL endpoint for CGI timescale service |url=http://resource.geosciml.org/sparql/isc2014 |url-status=dead |archive-url=https://archive.today/20140806164132/http://resource.geosciml.org/sparql/isc2014 |archive-date=2014-08-06 |access-date=2014-08-03}}</ref><ref name="Cox_2014">{{cite journal |last1=Cox |first1=Simon J. D. |last2=Richard |first2=Stephen M. |year=2014 |title=A geologic timescale ontology and service |journal=Earth Science Informatics |volume=8 |pages=5–19 |doi=10.1007/s12145-014-0170-6 |s2cid=42345393}}</ref> |
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The proposed [[Anthropocene]] epoch is not included. |
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{| class="wikitable collapsible" style="clear:both;margin:0; font-size:95%" |
{| class="wikitable collapsible" style="clear:both;margin:0; font-size:95%" |
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!Eonothem/<br/>Eon |
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!Erathem/<br/>Era |
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!System/<br/>Period |
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!Series/<br/>Epoch |
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!Stage/<br/>Age |
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!Major events |
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!Start, million years ago<br/>{{efn|The dates and uncertainties quoted are according to the [[International Commission on Stratigraphy]] International Chronostratigraphic chart (v2022/02). A <sup>*</sup> indicates boundaries where a [[Global Boundary Stratotype Section and Point]] has been internationally agreed upon.|name="ICC-dates"|group=note}} |
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|- |
|- |
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| rowspan="102" style="background:{{period color|Phanerozoic}}" |[[Phanerozoic]] |
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! [[Supereon (geology)|Supereon]] |
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| rowspan="24" style="background:{{period color|Cenozoic}}" |[[Cenozoic]]<br/>{{efn|name=Tertiary|group=note}} |
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! [[Eon (geology)|Eon]] |
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| rowspan="7" style="background:{{period color|Quaternary}}" |[[Quaternary]] |
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! [[Era (geology)|Era]] |
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| rowspan="3" style="background:{{period color|Holocene}}" |[[Holocene]] |
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! [[Period (geology)|Period]]{{efn|Paleontologists often refer to [[faunal stage]]s rather than geologic (geological) periods. The stage nomenclature is quite complex. For a time-ordered list of faunal stages, see.<ref name="faunal-stages">{{cite web |url=http://flatpebble.nceas.ucsb.edu/cgi-bin/bridge.pl?action=startScale |title=The Paleobiology Database |access-date=2006-03-19 |url-status=dead |archive-url=https://web.archive.org/web/20060211234211/http://flatpebble.nceas.ucsb.edu/cgi-bin/bridge.pl?action=startScale |archive-date=11 February 2006 |df=dmy }}</ref>}} |
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| style="background:#fcf0f2" |[[Meghalayan]] |
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! [[Epoch (geology)|Epoch]] |
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|[[4.2-kiloyear event]], [[Austronesian expansion]], increasing [[Industrial Revolution|industrial]] [[Carbon dioxide in the Earth's atmosphere|CO<sub>2</sub>]]. |
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! [[Age (geology)|Age]]{{efn|name="uncertain-dates"}} |
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| style="background:#fcf0f2" |{{Period start|meghalayan}} {{Period start error|meghalayan}}<sup>*</sup> |
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! Major events |
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! Start, million years ago{{efn|name="uncertain-dates"|Dates are slightly uncertain with differences of a few percent between various sources being common. This is largely due to uncertainties in [[radiometric dating]] and the problem that deposits suitable for radiometric dating seldom occur exactly at the places in the geologic column where they would be most useful. The dates and errors quoted above are according to the [[International Commission on Stratigraphy]] v2022/02 time scale except the Hadean eon. Where errors are not quoted, errors are less than the precision of the age given.<br /><br /><nowiki>*</nowiki> indicates boundaries where a [[Global Boundary Stratotype Section and Point]] has been internationally agreed upon.}} |
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|- |
|- |
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| style="background:#fcf0e8" |[[Northgrippian]] |
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|rowspan="102" style="background:#ffffff"| n/a{{efn|References to the "Post-Cambrian Supereon" are not universally accepted, and therefore must be considered unofficial.}} |
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|[[8.2-kiloyear event]], [[Holocene climatic optimum]]. [[Sea level]] flooding of [[Doggerland]] and [[Sundaland]]. [[Sahara]] becomes a desert. End of Stone Age and start of [[recorded history]]. Humans finally expand into the [[Arctic Archipelago]] and [[Greenland]]. |
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|rowspan="102" style="background:{{period color|Phanerozoic}}"| [[Phanerozoic]] |
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| style="background:#fcf0e8" |{{Period start|northgrippian}} {{Period start error|northgrippian}}<sup>*</sup> |
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|rowspan="24" style="background:{{period color|Cenozoic}}"| [[Cenozoic]]{{efn|Historically, the [[Cenozoic]] has been divided up into the [[Quaternary]] and [[Tertiary]] sub-eras, as well as the [[Neogene]] and [[Paleogene]] periods. The 2009 version of the ICS time chart<ref name="cenozoic-division">{{cite web |url=http://www.stratigraphy.org/upload/ISChart2009.pdf |title=Archived copy |access-date=2009-12-23 |url-status=dead |archive-url=https://web.archive.org/web/20091229003212/http://www.stratigraphy.org/upload/ISChart2009.pdf |archive-date=29 December 2009 |df=dmy-all }}</ref> recognizes a slightly extended Quaternary as well as the Paleogene and a truncated Neogene, the Tertiary having been demoted to informal status.}} |
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|rowspan="7" style="background:{{period color|Quaternary}}"| [[Quaternary]] |
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|rowspan="3" style="background:{{period color|Holocene}}"| [[Holocene]] |
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|style="background:#fcf0f2"|[[Meghalayan]] |
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|[[4.2-kiloyear event]], [[Austronesian expansion]] (finally occupying [[Madagascar]] and [[Remote Oceania]]), increasing [[Industrial Revolution|industrial]] [[Carbon dioxide in the Earth's atmosphere|CO<sub>2</sub>]]. |
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|style="background:#fcf0f2"| {{Period start|meghalayan}}<sup>*</sup> |
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|- |
|- |
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|style="background:# |
| style="background:#fcf0de" |[[Greenlandian]] |
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| |
|Climate stabilizes. Current [[interglacial]] and [[Holocene extinction]] begins. [[Neolithic revolution|Agriculture begins]]. Humans spread across the [[wet Sahara]] and [[Arabia]], the [[Extreme North]], and the Americas (mainland and the [[Caribbean]]). |
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|style="background:# |
| style="background:#fcf0de" |{{Period start|greenlandian}} {{Period start error|greenlandian}}<sup>*</sup> |
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|- |
|- |
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|style="background: |
| rowspan="4" style="background:{{period color|Pleistocene}}" |[[Pleistocene]] |
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| style="background:{{period color|Upper Pleistocene}}" |[[Late Pleistocene|Upper/Late]] ''('[[Tarantian]]')'' |
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|Climate stabilizes. Current [[interglacial]] and [[Holocene extinction]] begins. [[Neolithic revolution|Agriculture begins]]. Humans spread across the [[wet Sahara]] and [[Arabia]], the [[Extreme North]], and the Americas (mainland and the [[Caribbean]]). |
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|[[Eemian]] [[interglacial]], [[last glacial period]], ending with [[Younger Dryas]]. [[Toba catastrophe theory|Toba eruption]]. [[Quaternary extinction|Pleistocene megafauna (including the last terror birds) extinction]]. Humans expand into [[Near Oceania]] and the [[Americas]]. |
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|style="background:#fcf0de"| {{Period start|greenlandian}}<sup>*</sup> |
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| style="background:{{period color|upper Pleistocene}}" |{{Period start|Late pleistocene}} {{Period start error|Late pleistocene}} |
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|- |
|- |
||
| |
| style="background:{{period color|Middle Pleistocene}}" |[[Chibanian]] |
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|style="background:{{period color|Upper Pleistocene}}"| [[Late Pleistocene|Late]] ''('[[Tarantian]]')'' |
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|[[Eemian]] [[interglacial]], [[last glacial period]], ending with [[Younger Dryas]]. [[Toba catastrophe theory|Toba eruption]]. [[Quaternary extinction|Pleistocene megafauna (including the last terror birds) extinction]]. Humans expand into [[Near Oceania]] and the [[Americas]]. |
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|style="background:{{period color|upper Pleistocene}}"| {{Period start|Late pleistocene}} |
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|- |
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|style="background:{{period color|Middle Pleistocene}}"| [[Chibanian]] |
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|[[Mid-Pleistocene Transition]] occurs, high amplitude [[100,000-year problem|100 ka]] [[Glacial period|glacial cycles]]. Rise of [[Homo sapiens]]. |
|[[Mid-Pleistocene Transition]] occurs, high amplitude [[100,000-year problem|100 ka]] [[Glacial period|glacial cycles]]. Rise of [[Homo sapiens]]. |
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|style="background:{{period color|Middle Pleistocene}}"| {{Period start|middle pleistocene}}* |
| style="background:{{period color|Middle Pleistocene}}" |{{Period start|middle pleistocene}}{{Period start error|middle pleistocene}}<sup>*</sup> |
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|- |
|- |
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|style="background:{{period color|Calabrian}}" |
| style="background:{{period color|Calabrian}}" |[[Early Pleistocene|Calabrian]] |
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|Further cooling of the climate. Giant [[terror birds]] go extinct. Spread of [[Homo erectus]] across [[Afro-Eurasia]]. |
|Further cooling of the climate. Giant [[terror birds]] go extinct. Spread of [[Homo erectus]] across [[Afro-Eurasia]]. |
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|style="background:{{period color|Calabrian}}"| {{Period start|calabrian}}<sup>*</sup> |
| style="background:{{period color|Calabrian}}" |{{Period start|calabrian}} {{Period start error|calabrian}}<sup>*</sup> |
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|- |
|- |
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|style="background:{{period color|Gelasian}}" |
| style="background:{{period color|Gelasian}}" |[[Gelasian]] |
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|Start of [[Quaternary glaciation|Quaternary glaciations]] and unstable climate.<ref name="Hoag_2017">{{Cite journal |last=Hoag |first=Colin |last2=Svenning |first2=Jens-Christian |date=2017-10-17 |title=African Environmental Change from the Pleistocene to the Anthropocene |url=https://www.annualreviews.org/doi/10.1146/annurev-environ-102016-060653 |journal=Annual Review of Environment and Resources |language=en |volume=42 |issue=1 |pages=27–54 |doi=10.1146/annurev-environ-102016-060653 |issn=1543-5938}}</ref> Rise of the [[Pleistocene megafauna]] and [[Homo habilis]]. |
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|Start of [[Quaternary glaciation]]s and unstable climate.<ref>C. Hoag, J-C. Svenning |
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| style="background:{{period color|Gelasian}}" |{{Period start|gelasian}} {{Period start error|geliasian}}<sup>*</sup> |
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African environmental change from the Pleistocene to the Anthropocene Annu. Rev. Environ. Resour., 42 (2017), pp. 27-54, https://doi.org/10.1146/annurev-environ-102016-060653</ref> Rise of the [[Pleistocene megafauna]] and [[Homo habilis]]. |
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|style="background:{{period color|Gelasian}}"| {{Period start|gelasian}}<sup>*</sup> |
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|- |
|- |
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|rowspan="8" style="background:{{period color|Neogene}}" |
| rowspan="8" style="background:{{period color|Neogene}}" |[[Neogene]] |
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|rowspan="2" style="background:{{period color|Pliocene}}" |
| rowspan="2" style="background:{{period color|Pliocene}}" |[[Pliocene]] |
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|style="background:{{period color|Piacenzian}}" |
| style="background:{{period color|Piacenzian}}" |[[Piacenzian]] |
||
|[[Greenland ice sheet]] develops<ref>{{cite journal |
|[[Greenland ice sheet]] develops<ref name="Bartoli_2005">{{cite journal |last1=Bartoli |first1=G |last2=Sarnthein |first2=M |last3=Weinelt |first3=M |last4=Erlenkeuser |first4=H |last5=Garbe-Schönberg |first5=D |last6=Lea |first6=D.W |year=2005 |title=Final closure of Panama and the onset of northern hemisphere glaciation |journal=Earth and Planetary Science Letters |volume=237 |issue=1–2 |pages=33–44 |bibcode=2005E&PSL.237...33B |doi=10.1016/j.epsl.2005.06.020 |doi-access=free}}</ref> as the cold slowly intensifies towards the Pleistocene. Atmospheric {{O2}} and {{CO2}} content reaches present day levels while landmasses also reach their current locations (e.g. the [[Isthmus of Panama]] joins the [[North America|North]] and [[South America|South Americas]], while allowing [[Great American Interchange|a faunal interchange]]). The last non-marsupial metatherians go extinct. [[Australopithecus]] common in East Africa; [[Stone Age]] begins.<ref name="Tyson_2009">{{cite web |last=Tyson |first=Peter |date=October 2009 |title=NOVA, Aliens from Earth: Who's who in human evolution |url=https://www.pbs.org/wgbh/nova/hobbit/tree-nf.html |access-date=2009-10-08 |publisher=PBS}}</ref> |
||
|style="background:{{period color|Piacenzian}}"| {{Period start|piacenzian}}<sup>*</sup> |
| style="background:{{period color|Piacenzian}}" |{{Period start|piacenzian}} {{Period start error|piacenzian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Zanclean}}" |
| style="background:{{period color|Zanclean}}" |[[Zanclean]] |
||
|[[Zanclean flood]] |
|[[Zanclean flood|Zanclean flooding]] of the [[Mediterranean Basin]]. Cooling climate continues from the Miocene. First [[equines]] and [[Elephantimorpha|elephantines]]. [[Ardipithecus]] in Africa.<ref name="Tyson_2009" /> |
||
|style="background:{{period color|Zanclean}}"| {{Period start|zanclean}}<sup>*</sup> |
| style="background:{{period color|Zanclean}}" |{{Period start|zanclean}} {{Period start error|zanclean}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="6" style="background:{{period color|Miocene}}" |
| rowspan="6" style="background:{{period color|Miocene}}" |[[Miocene]] |
||
|style="background:{{period color|Messinian}}" |
| style="background:{{period color|Messinian}}" |[[Messinian]] |
||
|rowspan="2" |[[Messinian Event]] with hypersaline lakes in empty [[Mediterranean Basin]]. [[Greenhouse and Icehouse Earth|Moderate icehouse climate]], punctuated by [[ |
| rowspan="2" |[[Messinian Event]] with hypersaline lakes in empty [[Mediterranean Basin]]. [[Greenhouse and Icehouse Earth|Moderate icehouse climate]], punctuated by [[Ice age|ice ages]] and re-establishment of [[East Antarctic Ice Sheet]]. [[Choristodera|Choristoderes]], the last non-crocodilian [[Sebecosuchia|crocodylomorphs]] and [[creodonts]] go extinct. After [[Gorilla-human last common ancestor|separating from gorilla ancestors]], [[Chimpanzee–human last common ancestor|chimpanzee and human ancestors]] gradually separate; [[Sahelanthropus]] and [[Orrorin]] in Africa. |
||
|style="background:{{period color|Messinian}}"| {{Period start|messinian}}<sup>*</sup> |
| style="background:{{period color|Messinian}}" |{{Period start|messinian}} {{Period start error|messinian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Tortonian}}" |
| style="background:{{period color|Tortonian}}" |[[Tortonian]] |
||
|style="background:{{period color|Tortonian}}"| {{Period start|tortonian}}<sup>*</sup> |
| style="background:{{period color|Tortonian}}" |{{Period start|tortonian}} {{Period start error|tortonian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Serravallian}}" |
| style="background:{{period color|Serravallian}}" |[[Serravallian]] |
||
|rowspan="2" |Middle Miocene climate optimum temporarily provides a warm climate.<ref>https://digitalcommons.bryant.edu/ |
| rowspan="2" |Middle Miocene climate optimum temporarily provides a warm climate. <ref name="Gannon_2013_BryantUniHons">{{Cite journal |last=Gannon |first=Colin |date=2013-04-26 |title=Understanding the Middle Miocene Climatic Optimum: Evaluation of Deuterium Values (δD) Related to Precipitation and Temperature |url=https://digitalcommons.bryant.edu/honors_science/11 |journal=Honors Projects in Science and Technology}}</ref> Extinctions in [[middle Miocene disruption]], decreasing shark diversity. First [[Hippo|hippos]]. Ancestor of [[great apes]]. |
||
|style="background:{{period color|Serravallian}}"| {{Period start|serravallian}}<sup>*</sup> |
| style="background:{{period color|Serravallian}}" |{{Period start|serravallian}} {{Period start error|serravallian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Langhian}}" |
| style="background:{{period color|Langhian}}" |[[Langhian]] |
||
|style="background:{{period color|Langhian}}"| {{Period start|langhian}} |
| style="background:{{period color|Langhian}}" |{{Period start|langhian}} {{Period start error|langhian}} |
||
|- |
|- |
||
|style="background:{{period color|Burdigalian}}" |
| style="background:{{period color|Burdigalian}}" |[[Burdigalian]] |
||
|rowspan="2" |[[Orogeny]] in [[Northern Hemisphere]]. Start of [[Kaikoura Orogeny]] forming [[Southern Alps in New Zealand]]. Widespread forests slowly [[ |
| rowspan="2" |[[Orogeny]] in [[Northern Hemisphere]]. Start of [[Kaikoura Orogeny]] forming [[Southern Alps in New Zealand]]. Widespread forests slowly [[Photosynthesis|draw in]] massive amounts of {{CO2}}, gradually lowering the level of atmospheric {{CO2}} from 650 ppmv down to around 100 ppmv during the Miocene.<ref name="Royer_2006">{{cite journal |last1=Royer |first1=Dana L. |year=2006 |title=CO<sub>2</sub>-forced climate thresholds during the Phanerozoic |url=http://droyer.web.wesleyan.edu/PhanCO2%28GCA%29.pdf |url-status=dead |journal=Geochimica et Cosmochimica Acta |volume=70 |issue=23 |pages=5665–75 |bibcode=2006GeCoA..70.5665R |doi=10.1016/j.gca.2005.11.031 |archive-url=https://web.archive.org/web/20190927033455/http://droyer.web.wesleyan.edu/PhanCO2%28GCA%29.pdf |archive-date=27 September 2019 |access-date=6 August 2015}}</ref>{{efn|For more information on this, see [[Atmosphere of Earth#Evolution of Earth's atmosphere]], [[Carbon dioxide in the Earth's atmosphere]], and [[Climate variability and change|climate change]]. Specific graphs of reconstructed {{CO2}} levels over the past ~550, 65, and 5 million years can be seen at [[:File:Phanerozoic Carbon Dioxide.png]], [[:File:65 Myr Climate Change.png]], [[:File:Five Myr Climate Change.png]], respectively.|name="atmospheric-carbon-dioxide"|group=note}} Modern [[bird]] and mammal families become recognizable. The last of the primitive whales go extinct. [[Grass|Grasses]] become ubiquitous. Ancestor of [[apes]], including humans.<ref name="web_LS_2017">{{cite web |date=10 August 2017 |title=Here's What the Last Common Ancestor of Apes and Humans Looked Like |url=https://www.livescience.com/60093-last-common-ancestor-of-apes-humans-revealed.html |website=[[Live Science]]}}</ref><ref name="Nengo_2017">{{Cite journal |last=Nengo |first=Isaiah |last2=Tafforeau |first2=Paul |last3=Gilbert |first3=Christopher C. |last4=Fleagle |first4=John G. |last5=Miller |first5=Ellen R. |last6=Feibel |first6=Craig |last7=Fox |first7=David L. |last8=Feinberg |first8=Josh |last9=Pugh |first9=Kelsey D. |last10=Berruyer |first10=Camille |last11=Mana |first11=Sara |date=2017 |title=New infant cranium from the African Miocene sheds light on ape evolution |url=http://www.nature.com/articles/nature23456 |journal=Nature |language=en |volume=548 |issue=7666 |pages=169–174 |doi=10.1038/nature23456 |issn=0028-0836}}</ref> Afro-Arabia collides with Eurasia, fully forming the [[Alpide Belt]] and closing the Tethys Ocean, while allowing a faunal interchange. At the same time, Afro-Arabia splits into [[Africa]] and [[Arabian Plate|West Asia]]. |
||
|style="background:{{period color|Burdigalian}}"| {{Period start|burdigalian}} |
| style="background:{{period color|Burdigalian}}" |{{Period start|burdigalian}} {{Period start error|burdigalian}} |
||
|- |
|- |
||
|style="background:{{period color|Aquitanian}}" |
| style="background:{{period color|Aquitanian}}" |[[Aquitanian age|Aquitanian]] |
||
|style="background:{{period color|Aquitanian}}" |
| style="background:{{period color|Aquitanian}}" |{{Period start|aquitanian}} {{Period start error|anquitanian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="9" style="background:{{period color|Paleogene}}" |
| rowspan="9" style="background:{{period color|Paleogene}}" |[[Paleogene]] |
||
|rowspan="2" style="background:{{period color|Oligocene}}" |
| rowspan="2" style="background:{{period color|Oligocene}}" |[[Oligocene]] |
||
|style="background:{{period color|Chattian}}" |
| style="background:{{period color|Chattian}}" |[[Chattian]] |
||
|rowspan="2" |
| rowspan="2" |[[Eocene–Oligocene extinction event|Grande Coupure]] extinction. Start of widespread [[Late Cenozoic Ice Age|Antarctic glaciation]].<ref name="Deconto_2003">{{Cite journal |last1=Deconto |first1=Robert M. |last2=Pollard |first2=David |year=2003 |title=Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2 |journal=Nature |volume=421 |issue=6920 |pages=245–249 |bibcode=2003Natur.421..245D |doi=10.1038/nature01290 |pmid=12529638 |s2cid=4326971}}</ref> Rapid [[evolution]] and diversification of fauna, especially [[Mammal|mammals]] (e.g. first [[Macropodiformes|macropods]] and [[Pinnipedia|seals]]). Major evolution and dispersal of modern types of [[Flowering plant|flowering plants]]. [[Cimolesta|Cimolestans]], miacoids and condylarths go extinct. First [[Cetacea|neocetes]] (modern, fully aquatic whales) appear. |
||
|style="background:{{period color|Chattian}}"| {{Period start|chattian}} |
| style="background:{{period color|Chattian}}" |{{Period start|chattian}} {{Period start error|chattian}} |
||
|- |
|- |
||
|style="background:{{period color|Rupelian}}" |
| style="background:{{period color|Rupelian}}" |[[Rupelian]] |
||
|style="background:{{period color|Rupelian}}"| {{Period start|rupelian}}<sup>*</sup> |
| style="background:{{period color|Rupelian}}" |{{Period start|rupelian}} {{Period start error|rupelian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="4" style="background:{{period color|Eocene}}" |
| rowspan="4" style="background:{{period color|Eocene}}" |[[Eocene]] |
||
|style="background:{{period color|Priabonian}}" |
| style="background:{{period color|Priabonian}}" |[[Priabonian]] |
||
|rowspan="3" |
| rowspan="3" |[[Greenhouse and Icehouse Earth|Moderate, cooling climate]]. Archaic [[Mammal|mammals]] (e.g. [[Creodont|creodonts]], [[Miacoidea|miacoids]], "[[Condylarth|condylarths]]" etc.) flourish and continue to develop during the epoch. Appearance of several "modern" mammal families. [[Archaeoceti|Primitive whales]] and [[sea cows]] diversify after returning to water. [[Birds]] continue to diversify. First [[kelp]], [[Diprotodontia|diprotodonts]], [[bears]] and [[simians]]. The multituberculates and leptictidans go extinct by the end of the epoch. Reglaciation of Antarctica and formation of its [[ice cap]]; End of [[Laramide Orogeny|Laramide]] and [[Sevier orogeny|Sevier Orogenies]] of the [[Rocky Mountains]] in North America. [[Hellenic orogeny|Hellenic Orogeny]] begins in Greece and [[Aegean Sea]]. |
||
|style="background:{{period color|Priabonian}}"| {{Period start|priabonian}}* |
| style="background:{{period color|Priabonian}}" |{{Period start|priabonian}} {{Period start error|priabonian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Bartonian}}" |
| style="background:{{period color|Bartonian}}" |[[Bartonian]] |
||
|style="background:{{period color|Bartonian}}"| {{Period start|bartonian}} |
| style="background:{{period color|Bartonian}}" |{{Period start|bartonian}} {{Period start error|bartonian}} |
||
|- |
|- |
||
|style="background:{{period color|Lutetian}}" |
| style="background:{{period color|Lutetian}}" |[[Lutetian]] |
||
|style="background:{{period color|Lutetian}}"| {{Period start|lutetian}}<sup>*</sup> |
| style="background:{{period color|Lutetian}}" |{{Period start|lutetian}} {{Period start error|lutetian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Ypresian}}" |
| style="background:{{period color|Ypresian}}" |[[Ypresian]] |
||
|Two transient events of global warming ([[Paleocene–Eocene Thermal Maximum|PETM]] and [[Eocene Thermal Maximum 2|ETM-2]]) and warming climate until the [[Eocene Climatic Optimum]]. The [[Azolla event]] decreased {{CO2}} levels from 3500 ppm to 650 ppm, setting the stage for a long period of cooling.<ref name=" |
|Two transient events of global warming ([[Paleocene–Eocene Thermal Maximum|PETM]] and [[Eocene Thermal Maximum 2|ETM-2]]) and warming climate until the [[Eocene Climatic Optimum]]. The [[Azolla event]] decreased {{CO2}} levels from 3500 ppm to 650 ppm, setting the stage for a long period of cooling.<ref name="Royer_2006" />{{efn|name="atmospheric-carbon-dioxide"|group=note}} [[Indian subcontinent|Greater India]] collides with Eurasia and starts [[Geology of the Himalaya|Himalayan Orogeny]] (allowing a [[biotic interchange]]) while Eurasia completely separates from North America, creating the [[North Atlantic Ocean]]. [[Maritime Southeast Asia]] diverges from the rest of Eurasia. First [[passerines]], [[ruminants]], [[pangolins]], [[bats]] and true [[primates]]. |
||
|style="background:{{period color|Ypresian}}"| {{Period start|ypresian}}<sup>*</sup> |
| style="background:{{period color|Ypresian}}" |{{Period start|ypresian}} {{Period start error|ypresian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="3" style="background:{{period color|Paleocene}}" |
| rowspan="3" style="background:{{period color|Paleocene}}" |[[Paleocene]] |
||
|style="background:{{period color|Thanetian}}" |
| style="background:{{period color|Thanetian}}" |[[Thanetian]] |
||
|rowspan="3" |
| rowspan="3" |Starts with [[Chicxulub impact]] and the [[K-Pg extinction event]], wiping out all non-avian dinosaurs and pterosaurs, most marine reptiles, many other vertebrates (e.g. many Laurasian metatherians), most cephalopods (only [[Nautilidae]] and [[Coleoidea]] survived) and many other invertebrates. [[Greenhouse and Icehouse Earth|Climate tropical]]. [[Mammals]] and [[birds]] (avians) diversify rapidly into a number of lineages following the extinction event (while the marine revolution stops). Multituberculates and the first [[rodents]] widespread. First large birds (e.g. [[ratites]] and [[terror birds]]) and mammals (up to bear or small hippo size). [[Alpine orogeny]] in Europe and Asia begins. First [[Proboscidea|proboscideans]] and [[plesiadapiformes]] (stem primates) appear. [[Australidelphia|Some marsupials]] migrate to Australia. |
||
|style="background:{{period color|Thanetian}}"| {{Period start|thanetian}}<sup>*</sup> |
| style="background:{{period color|Thanetian}}" |{{Period start|thanetian}} {{Period start error|thanetian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Selandian}}" |
| style="background:{{period color|Selandian}}" |[[Selandian]] |
||
|style="background:{{period color|Selandian}}"| {{Period start|selandian}}<sup>*</sup> |
| style="background:{{period color|Selandian}}" |{{Period start|selandian}} {{Period start error|selandian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Danian}}" |
| style="background:{{period color|Danian}}" |[[Danian]] |
||
|style="background:{{period color|Danian}}"| {{Period start|danian}}<sup>*</sup> |
| style="background:{{period color|Danian}}" |{{Period start|danian}} {{Period start error|danian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="30" style="background:{{period color|Mesozoic}}" |
| rowspan="30" style="background:{{period color|Mesozoic}}" |[[Mesozoic]] |
||
|rowspan="12" style="background:{{period color|Cretaceous}}" | |
| rowspan="12" style="background:{{period color|Cretaceous}}" |[[Cretaceous]] |
||
|rowspan="6" style="background:{{period color|Late Cretaceous}}" |
| rowspan="6" style="background:{{period color|Late Cretaceous}}" |[[Late Cretaceous|Upper/Late]] |
||
|style="background:{{period color|Maastrichtian}}" |
| style="background:{{period color|Maastrichtian}}" |[[Maastrichtian]] |
||
|rowspan="12" |
| rowspan="12" |[[Flowering plant|Flowering plants]] proliferate (after developing many features since the Carboniferous), along with new types of [[Insect|insects]], while other seed plants (gymnosperms and seed ferns) decline. More modern [[teleost]] fish begin to appear. [[Ammonoids]], [[Belemnoidea|belemnites]], [[rudist]] [[Bivalve|bivalves]], [[sea urchins]] and [[sponges]] all common. Many new types of [[Dinosaur|dinosaurs]] (e.g. [[Tyrannosauridae|tyrannosaurs]], [[Titanosauridae|titanosaurs]], [[Hadrosauridae|hadrosaurs]], and [[Ceratopsidae|ceratopsids]]) evolve on land, while [[Crocodilia|crocodilians]] appear in water and probably cause the last temnospondyls to die out; and [[Mosasaur|mosasaurs]] and modern types of sharks appear in the sea. The revolution started by marine reptiles and sharks reaches its peak, though ichthyosaurs vanish few million years after being heavily reduced at the [[Bonarelli Event]]. Toothed and [[Neornithes|toothless avian birds]] coexist with pterosaurs. Modern [[monotremes]], [[Metatheria|metatherian]] (including [[marsupials]], who migrate to South America) and [[Eutheria|eutherian]] (including [[placentals]], [[Leptictida|leptictidans]] and [[Cimolesta|cimolestans]]) mammals appear while the last non-mammalian cynodonts die out. First [[terrestrial crabs]]. Many snails become terrestrial. Further breakup of Gondwana creates [[South America]], [[Africa|Afro-]][[West Asia|Arabia]], [[Antarctica]], [[Oceania]], [[Madagascar]], [[Indian subcontinent|Greater India]], and the [[South Atlantic]], [[Indian Ocean|Indian]] and [[Antarctic Ocean|Antarctic Oceans]] and the islands of the Indian (and some of the Atlantic) Ocean. Beginning of [[Laramide Orogeny|Laramide]] and [[Sevier Orogeny|Sevier Orogenies]] of the [[Rocky Mountains]]. [[Atmosphere of Earth|Atmospheric]] oxygen and carbon dioxide levels similar to present day. [[Acritarch|Acritarchs]] disappear. Climate initially warm, but later it cools. |
||
|style="background:{{period color|Maastrichtian}}" |
| style="background:{{period color|Maastrichtian}}" |{{Period start|maastrichtian}} {{Period start error|maastrichtian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Campanian}}" |
| style="background:{{period color|Campanian}}" |[[Campanian]] |
||
|style="background:{{period color|Campanian}}" |
| style="background:{{period color|Campanian}}" |{{Period start|campanian}} {{Period start error|campanian}} |
||
|- |
|- |
||
|style="background:{{period color|Santonian}}" |
| style="background:{{period color|Santonian}}" |[[Santonian]] |
||
|style="background:{{period color|Santonian}}" |
| style="background:{{period color|Santonian}}" |{{Period start|santonian}} {{Period start error|santonian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Coniacian}}" |
| style="background:{{period color|Coniacian}}" |[[Coniacian]] |
||
|style="background:{{period color|Coniacian}}" |
| style="background:{{period color|Coniacian}}" |{{Period start|coniacian}} {{Period start error|coniacian}} |
||
|- |
|- |
||
|style="background:{{period color|Turonian}}" |
| style="background:{{period color|Turonian}}" |[[Turonian]] |
||
|style="background:{{period color|Turonian}}"| {{Period start|turonian}}<sup>*</sup> |
| style="background:{{period color|Turonian}}" |{{Period start|turonian}} {{Period start error|turonian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Cenomanian}}" |
| style="background:{{period color|Cenomanian}}" |[[Cenomanian]] |
||
|style="background:{{period color|Cenomanian}}"| {{Period start|cenomanian}}<sup>*</sup> |
| style="background:{{period color|Cenomanian}}" |{{Period start|cenomanian}} {{Period start error|cenomanian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="6" style="background:{{period color|Early Cretaceous}}" |
| rowspan="6" style="background:{{period color|Early Cretaceous}}" |[[Early Cretaceous|Lower/Early]] |
||
|style="background:{{period color|Albian}}" |
| style="background:{{period color|Albian}}" |[[Albian]] |
||
|style="background:{{period color|Albian}}" |
| style="background:{{period color|Albian}}" |~{{Period start|albian}} {{Period start error|albian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Aptian}}" |
| style="background:{{period color|Aptian}}" |[[Aptian]] |
||
|style="background:{{period color|Aptian}}" |
| style="background:{{period color|Aptian}}" |~{{Period start|aptian}} {{Period start error|aptian}} |
||
|- |
|- |
||
|style="background:{{period color|Barremian}}" |
| style="background:{{period color|Barremian}}" |[[Barremian]] |
||
|style="background:{{period color|Barremian}}" |
| style="background:{{period color|Barremian}}" |~{{Period start|barremian}} {{Period start error|barremian}} |
||
|- |
|- |
||
|style="background:{{period color|Hauterivian}}" |
| style="background:{{period color|Hauterivian}}" |[[Hauterivian]] |
||
|style="background:{{period color|Hauterivian}}" |
| style="background:{{period color|Hauterivian}}" |~{{Period start|hauterivian}} {{Period start error|hauterivian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Valanginian}}" |
| style="background:{{period color|Valanginian}}" |[[Valanginian]] |
||
|style="background:{{period color|Valanginian}}" |
| style="background:{{period color|Valanginian}}" |~{{Period start|valanginian}} {{Period start error|valanginian}} |
||
|- |
|- |
||
|style="background:{{period color|Berriasian}}" |
| style="background:{{period color|Berriasian}}" |[[Berriasian]] |
||
|style="background:{{period color|Berriasian}}" |
| style="background:{{period color|Berriasian}}" |~{{Period start|berriasian}} {{Period start error|berriasian}} |
||
|- |
|- |
||
|rowspan="11" style="background:{{period color|Jurassic}}" |
| rowspan="11" style="background:{{period color|Jurassic}}" |[[Jurassic]] |
||
|rowspan="3" style="background:{{period color|Late Jurassic}}" |
| rowspan="3" style="background:{{period color|Late Jurassic}}" |[[Late Jurassic|Upper/Late]] |
||
|style="background:{{period color|Tithonian}}" |
| style="background:{{period color|Tithonian}}" |[[Tithonian]] |
||
|rowspan="11" |
| rowspan="11" |Climate becomes humid again. [[Gymnosperm|Gymnosperms]] (especially [[Conifer|conifers]], [[Cycad|cycads]] and [[cycadeoids]]) and [[Fern|ferns]] common. [[Dinosaur|Dinosaurs]], including [[Sauropod|sauropods]], [[Carnosaur|carnosaurs]], [[Stegosaur|stegosaurs]] and [[Coelurosaur|coelurosaurs]], become the dominant land vertebrates. Mammals diversify into [[Shuotheriidae|shuotheriids]], [[Australosphenida|australosphenidans]], [[eutriconodonts]], [[multituberculates]], [[symmetrodonts]], [[dryolestids]] and [[Boreosphenida|boreosphenidans]] but mostly remain small. First [[Avialae|birds]], [[Squamata|lizards, snakes]] and [[turtles]]. First [[brown algae]], [[Batoidea|rays]], [[shrimps]], [[crabs]] and [[lobsters]]. [[Parvipelvia|Parvipelvian]] ichthyosaurs and [[Plesiosaur|plesiosaurs]] diverse. Rhynchocephalians throughout the world. [[Bivalve|Bivalves]], [[Ammonoid|ammonoids]] and [[Belemnoidea|belemnites]] abundant. [[Sea urchin|Sea urchins]] very common, along with [[Crinoid|crinoids]], [[starfish]], [[Porifera|sponges]], and [[Terebratulida|terebratulid]] and [[Rhynchonellida|rhynchonellid]] [[Brachiopod|brachiopods]]. Breakup of [[Pangaea]] into [[Laurasia]] and [[Gondwana]], with the latter also breaking into two main parts; the [[Pacific]] and [[Arctic Ocean|Arctic Oceans]] form. [[Tethys Ocean]] forms. [[Nevadan orogeny]] in North America. [[Rangitata Orogeny|Rangitata]] and [[Cimmerian Orogeny|Cimmerian orogenies]] taper off. Atmospheric {{CO2}} levels 3–4 times the present day levels (1200–1500 ppmv, compared to today's 400 ppmv<ref name="Royer_2006" />{{efn|name="atmospheric-carbon-dioxide"|group=note}}). [[Crocodylomorph|Crocodylomorphs]] (last pseudosuchians) seek out an aquatic lifestyle. [[Mesozoic marine revolution]] continues from late Triassic. [[Tentaculita|Tentaculitans]] disappear. |
||
|style="background:{{period color|Tithonian}}" |
| style="background:{{period color|Tithonian}}" |{{Period start|tithonian}} {{Period start error|tithonian}} |
||
|- |
|- |
||
|style="background:{{period color|Kimmeridgian}}" |
| style="background:{{period color|Kimmeridgian}}" |[[Kimmeridgian]] |
||
|style="background:{{period color|Kimmeridgian}}" |
| style="background:{{period color|Kimmeridgian}}" |{{Period start|kimmeridgian}} {{Period start error|kimmeridgian}} |
||
|- |
|- |
||
|style="background:{{period color|Oxfordian}}" |
| style="background:{{period color|Oxfordian}}" |[[Oxfordian stage|Oxfordian]] |
||
|style="background:{{period color|Oxfordian}}" |
| style="background:{{period color|Oxfordian}}" |{{Period start|oxfordian}} {{Period start error|oxfordian}} |
||
|- |
|- |
||
|rowspan="4" style="background:{{period color|Middle Jurassic}}" |
| rowspan="4" style="background:{{period color|Middle Jurassic}}" |[[Middle Jurassic|Middle]] |
||
|style="background:{{period color|Callovian}}" |
| style="background:{{period color|Callovian}}" |[[Callovian]] |
||
|style="background:{{period color|Callovian}}" |
| style="background:{{period color|Callovian}}" |{{Period start|callovian}} {{Period start error|callovian}} |
||
|- |
|- |
||
|style="background:{{period color|Bathonian}}" |
| style="background:{{period color|Bathonian}}" |[[Bathonian]] |
||
|style="background:{{period color|Bathonian}}" |
| style="background:{{period color|Bathonian}}" |{{Period start|bathonian}} {{Period start error|bathonian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Bajocian}}" |
| style="background:{{period color|Bajocian}}" |[[Bajocian]] |
||
|style="background:{{period color|Bajocian}}" |
| style="background:{{period color|Bajocian}}" |{{Period start|bajocian}} {{Period start error|bajocian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Aalenian}}" |
| style="background:{{period color|Aalenian}}" |[[Aalenian]] |
||
|style="background:{{period color|Aalenian}}" |
| style="background:{{period color|Aalenian}}" |{{Period start|aalenian}} {{Period start error|aalenian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="4" style="background:{{period color|Early Jurassic}}" |
| rowspan="4" style="background:{{period color|Early Jurassic}}" |[[Early Jurassic|Lower/Early]] |
||
|style="background:{{period color|Toarcian}}" |
| style="background:{{period color|Toarcian}}" |[[Toarcian]] |
||
|style="background:{{period color|Toarcian}}" |
| style="background:{{period color|Toarcian}}" |{{Period start|toarcian}} {{Period start error|toarcian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Pliensbachian}}" |
| style="background:{{period color|Pliensbachian}}" |[[Pliensbachian]] |
||
|style="background:{{period color|Pliensbachian}}" |
| style="background:{{period color|Pliensbachian}}" |{{Period start|pliensbachian}} {{Period start error|pleinsbachian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Sinemurian}}" |
| style="background:{{period color|Sinemurian}}" |[[Sinemurian]] |
||
|style="background:{{period color|Sinemurian}}" |
| style="background:{{period color|Sinemurian}}" |{{Period start|sinemurian}} {{Period start error|sinemurian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Hettangian}}" |
| style="background:{{period color|Hettangian}}" |[[Hettangian]] |
||
|style="background:{{period color|Hettangian}}" |
| style="background:{{period color|Hettangian}}" |{{Period start|hettangian}} {{Period start error|hettangian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="7" style="background:{{period color|Triassic}}" |
| rowspan="7" style="background:{{period color|Triassic}}" |[[Triassic]] |
||
|rowspan="3" style="background:{{period color|Late Triassic}}" |
| rowspan="3" style="background:{{period color|Late Triassic}}" |[[Late Triassic|Upper/Late]] |
||
|style="background:{{period color|Rhaetian}}" |
| style="background:{{period color|Rhaetian}}" |[[Rhaetian]] |
||
|rowspan="7" |
| rowspan="7" |[[Archosaur|Archosaurs]] dominant on land as [[Pseudosuchia|pseudosuchians]] and in the air as [[Pterosaur|pterosaurs]]. [[Dinosaurs]] also arise from bipedal archosaurs. [[Ichthyosaur|Ichthyosaurs]] and [[Nothosaur|nothosaurs]] (a group of sauropterygians) dominate large marine fauna. [[Cynodont|Cynodonts]] become smaller and nocturnal, eventually becoming the first true [[mammals]], while other remaining synapsids die out. [[Rhynchosaur|Rhynchosaurs]] (archosaur relatives) also common. [[Seed ferns]] called ''[[Dicroidium]]'' remained common in Gondwana, before being replaced by advanced gymnosperms. Many large aquatic [[Temnospondyli|temnospondyl]] amphibians. [[Ceratitida|Ceratitidan]] [[ammonoids]] extremely common. [[Scleractinia|Modern corals]] and [[teleost]] fish appear, as do many modern [[insect]] orders and suborders. First [[starfish]]. [[Andes Mountains|Andean Orogeny]] in South America. [[Cimmerian Orogeny]] in Asia. [[Rangitata Orogeny]] begins in New Zealand. [[Hunter-Bowen Orogeny]] in [[Northern Australia]], Queensland and [[New South Wales]] ends, (c. 260–225 Ma). [[Carnian pluvial event]] occurs around 234-232 Ma, allowing the first dinosaurs and [[lepidosaurs]] (including [[Rhynchocephalia|rhynchocephalians]]) to radiate. [[Triassic-Jurassic extinction event]] occurs 201 Ma, wiping out all [[conodonts]] and the [[Procolophonidae|last parareptiles]], many marine reptiles (e.g. all sauropterygians except [[plesiosaurs]] and all ichthyosaurs except [[Parvipelvia|parvipelvians]]), all [[Crocopoda|crocopodans]] except crocodylomorphs, pterosaurs, and dinosaurs, and many ammonoids (including the whole [[Ceratitida]]), bivalves, brachiopods, corals and sponges. First [[diatoms]].<ref name="Medlin_1997">{{cite journal |last1=Medlin |first1=L. K. |last2=Kooistra |first2=W. H. C. F. |last3=Gersonde |first3=R. |last4=Sims |first4=P. A. |last5=Wellbrock |first5=U. |year=1997 |title=Is the origin of the diatoms related to the end-Permian mass extinction? |journal=Nova Hedwigia |volume=65 |issue=1–4 |pages=1–11 |doi=10.1127/nova.hedwigia/65/1997/1 |hdl=10013/epic.12689}}</ref> |
||
|style="background:{{period color|Rhaetian}}" |
| style="background:{{period color|Rhaetian}}" |~{{Period start|rhaetian}} {{Period start error|rhaetian}} |
||
|- |
|- |
||
|style="background:{{period color|Norian}}" |
| style="background:{{period color|Norian}}" |[[Norian]] |
||
|style="background:{{period color|Norian}}" |
| style="background:{{period color|Norian}}" |~{{Period start|norian}} {{Period start error|norian}} |
||
|- |
|- |
||
|style="background:{{period color|Carnian}}" |
| style="background:{{period color|Carnian}}" |[[Carnian]] |
||
|style="background:{{period color|Carnian}}" |
| style="background:{{period color|Carnian}}" |~{{Period start|carnian}} {{Period start error|carnian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Middle Triassic}}" |
| rowspan="2" style="background:{{period color|Middle Triassic}}" |[[Middle Triassic|Middle]] |
||
|style="background:{{period color|Ladinian}}" |
| style="background:{{period color|Ladinian}}" |[[Ladinian]] |
||
|style="background:{{period color|Ladinian}}" |
| style="background:{{period color|Ladinian}}" |~{{Period start|ladinian}} {{Period start error|ladnian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Anisian}}" |
| style="background:{{period color|Anisian}}" |[[Anisian]] |
||
|style="background:{{period color|Anisian}}"| {{Period start|anisian}} |
| style="background:{{period color|Anisian}}" |{{Period start|anisian}} {{Period start error|anisian}} |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Early Triassic}}" |
| rowspan="2" style="background:{{period color|Early Triassic}}" |[[Early Triassic|Lower/Early]] |
||
|style="background:{{period color|Olenekian}}" |
| style="background:{{period color|Olenekian}}" |[[Olenekian]] |
||
|style="background:{{period color|Olenekian}}"| {{Period start|olenekian}} |
| style="background:{{period color|Olenekian}}" |{{Period start|olenekian}} {{Period start error|olenekian}} |
||
|- |
|- |
||
|style="background:{{period color|Induan}}" |
| style="background:{{period color|Induan}}" |[[Induan]] |
||
|style="background:{{period color|Induan}}" |
| style="background:{{period color|Induan}}" |{{Period start|induan}} {{Period start error|induan}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="48" style="background:{{period color|Paleozoic}}" |
| rowspan="48" style="background:{{period color|Paleozoic}}" |[[Paleozoic]] |
||
|rowspan="9" style="background:{{period color|Permian}}" |
| rowspan="9" style="background:{{period color|Permian}}" |[[Permian]] |
||
|rowspan="2" style="background:{{period color|Lopingian}}" |
| rowspan="2" style="background:{{period color|Lopingian}}" |[[Lopingian]] |
||
|style="background:{{period color|Changhsingian}}" |
| style="background:{{period color|Changhsingian}}" |[[Changhsingian]] |
||
|rowspan="9" |
| rowspan="9" |[[Landmass|Landmasses]] unite into [[supercontinent]] [[Pangaea]], creating the [[Urals]], [[Ouachitas]] and [[Appalachian Mountains|Appalachians]], among other mountain ranges (the superocean [[Panthalassa]] or Proto-Pacific also forms). End of Permo-Carboniferous glaciation. Hot and dry climate. A possible drop in oxygen levels. [[Synapsida|Synapsids]] ([[Pelycosaur|pelycosaurs]] and [[Therapsid|therapsids]]) become widespread and dominant, while [[Parareptile|parareptiles]] and [[Temnospondyli|temnospondyl]] [[Amphibian|amphibians]] remain common, with the latter probably giving rise to [[Lissamphibia|modern amphibians]] in this period. In the mid-Permian, lycophytes are heavily replaced by ferns and seed plants. [[Beetles]] and [[Fly|flies]] evolve. The very large arthropods and non-tetrapod tetrapodomorphs go extinct. Marine life flourishes in warm shallow reefs; [[Productida|productid]] and [[Spiriferida|spiriferid]] brachiopods, bivalves, [[Foram|forams]], ammonoids (including goniatites), and [[Orthocerida|orthoceridans]] all abundant. [[Sauria|Crown reptiles]] arise from earlier diapsids, and split into the ancestors of [[Lepidosauromorpha|lepidosaurs]], [[Kuehneosauridae|kuehneosaurids]], [[Choristodera|choristoderes]], [[Crocopoda|archosaurs]], [[Testudinata|testudinatans]], [[Ichthyosauromorpha|ichthyosaurs]], [[thalattosaurs]], and [[Sauropterygia|sauropterygians]]. Cynodonts evolve from larger therapsids. [[Olson's Extinction]] (273 Ma), [[Capitanian mass extinction event|End-Capitanian extinction]] (260 Ma), and [[Permian-Triassic extinction event]] (252 Ma) occur one after another: more than 80% of life on Earth becomes extinct in the lattermost, including most [[Retaria|retarian]] plankton, corals ([[Tabulata]] and [[Rugosa]] die out fully), brachiopods, bryozoans, gastropods, ammonoids (the goniatites die off fully), insects, parareptiles, synapsids, amphibians, and crinoids (only [[Articulata (Crinoidea)|articulates]] survived), and all [[Eurypterid|eurypterids]], [[Trilobite|trilobites]], [[Graptolite|graptolites]], [[hyoliths]], [[Edrioasteroidea|edrioasteroid crinozoans]], [[Blastoid|blastoids]] and [[acanthodians]]. [[Ouachita Orogeny|Ouachita]] and [[Innuitian orogeny|Innuitian orogenies]] in North America. [[Uralian orogeny]] in Europe/Asia tapers off. [[Altai Mountains|Altaid]] orogeny in Asia. [[Hunter-Bowen Orogeny]] on [[Australia (continent)|Australian continent]] begins (c. 260–225 Ma), forming the [[MacDonnell Ranges]]. |
||
|style="background:{{period color|Changhsingian}}" |
| style="background:{{period color|Changhsingian}}" |{{Period start|changhsingian}} {{Period start error|changhsingian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Wuchiapingian}}" |
| style="background:{{period color|Wuchiapingian}}" |[[Wuchiapingian]] |
||
|style="background:{{period color|Wuchiapingian}}" |
| style="background:{{period color|Wuchiapingian}}" |{{Period start|wuchiapingian}} {{Period start error|wuchiapingian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="3" style="background:{{period color|Guadalupian}}" |
| rowspan="3" style="background:{{period color|Guadalupian}}" |[[Guadalupian]] |
||
|style="background:{{period color|Capitanian}}" |
| style="background:{{period color|Capitanian}}" |[[Capitanian]] |
||
|style="background:{{period color|Capitanian}}" |
| style="background:{{period color|Capitanian}}" |{{Period start|capitanian}} {{Period start error|capitanian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Wordian}}" |
| style="background:{{period color|Wordian}}" |[[Wordian]] |
||
|style="background:{{period color|Wordian}}" |
| style="background:{{period color|Wordian}}" |{{Period start|wordian}} {{Period start error|wordian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Roadian}}" |
| style="background:{{period color|Roadian}}" |[[Roadian]] |
||
|style="background:{{period color|Roadian}}" |
| style="background:{{period color|Roadian}}" |{{Period start|roadian}} {{Period start error|roadian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="4" style="background:{{period color|Cisuralian}}" |
| rowspan="4" style="background:{{period color|Cisuralian}}" |[[Cisuralian]] |
||
|style="background:{{period color|Kungurian}}" |
| style="background:{{period color|Kungurian}}" |[[Kungurian]] |
||
|style="background:{{period color|Kungurian}}" |
| style="background:{{period color|Kungurian}}" |{{Period start|kungurian}} {{Period start error|kungurian}} |
||
|- |
|- |
||
|style="background:{{period color|Artinskian}}" |
| style="background:{{period color|Artinskian}}" |[[Artinskian]] |
||
|style="background:{{period color|Artinskian}}" |
| style="background:{{period color|Artinskian}}" |{{Period start|artinskian}} {{Period start error|artinskian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Sakmarian}}" |
| style="background:{{period color|Sakmarian}}" |[[Sakmarian]] |
||
|style="background:{{period color|Sakmarian}}" |
| style="background:{{period color|Sakmarian}}" |{{Period start|sakmarian}} {{Period start error|sakmarian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Asselian}}" |
| style="background:{{period color|Asselian}}" |[[Asselian]] |
||
|style="background:{{period color|Asselian}}" |
| style="background:{{period color|Asselian}}" |{{Period start|asselian}} {{Period start error|asselian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="7" style="background:{{period color|Carboniferous}}" |
| rowspan="7" style="background:{{period color|Carboniferous}}" |[[Carboniferous]]<br/>{{efn|The [[Mississippian (geology)|Mississippian]] and [[Pennsylvanian (geology)|Pennsylvanian]] are official sub-systems/sub-periods.|name=CarboSub|group=note}} |
||
|rowspan="4" style="background:{{period color|Pennsylvanian}}" |
| rowspan="4" style="background:{{period color|Pennsylvanian}}" |[[Pennsylvanian (geology)|Pennsylvanian]]<br/>{{efn|group=note|name=MissiPenns|This is divided into Lower/Early, Middle, and Upper/Late series/epochs}} |
||
|style="background:{{period color|Gzhelian}}" |
| style="background:{{period color|Gzhelian}}" |[[Gzhelian]] |
||
|rowspan="4" |
| rowspan="4" |[[Pterygota|Winged insects]] radiate suddenly; some (esp. [[Protodonata]] and [[Palaeodictyoptera]]) of them as well some [[Millipede|millipedes]] and [[Scorpion|scorpions]] become very large. First [[coal]] forests ([[Lepidodendron|scale trees]], ferns, [[Sigillaria|club trees]], [[Calamites|giant horsetails]], ''[[Cordaites]]'', etc.). Higher [[Atmosphere of Earth|atmospheric]] [[oxygen]] levels. [[Permo-Carboniferous|Ice Age]] continues to the Early Permian. [[Goniatite|Goniatites]], brachiopods, bryozoa, bivalves, and corals plentiful in the seas and oceans. First [[woodlice]]. Testate [[Foram|forams]] proliferate. [[Euramerica]] collides with [[Gondwana]] and Siberia-Kazakhstania, the latter of which forms [[Laurasia]] and the [[Uralian orogeny]]. Variscan orogeny continues (these collisions created orogenies, and ultimately [[Pangaea]]). [[Amphibian|Amphibians]] (e.g. temnospondyls) spread in Euramerica, with some becoming the first [[amniotes]]. [[Carboniferous Rainforest Collapse]] occurs, initiating a dry climate which favors amniotes over amphibians. Amniotes diversify rapidly into [[synapsids]], [[parareptiles]], [[Captorhinidae|cotylosaurs]], [[protorothyridids]] and [[diapsids]]. [[Rhizodont|Rhizodonts]] remained common before they died out by the end of the period. First [[sharks]]. |
||
|style="background:{{period color|Gzhelian}}" |
| style="background:{{period color|Gzhelian}}" |{{Period start|gzhelian}} {{Period start error|gzhelain}} |
||
|- |
|- |
||
|style="background:{{period color|Kasimovian}}" |
| style="background:{{period color|Kasimovian}}" |[[Kasimovian]] |
||
|style="background:{{period color|Kasimovian}}" |
| style="background:{{period color|Kasimovian}}" |{{Period start|kasimovian}} {{Period start error|kasimovian}} |
||
|- |
|- |
||
|style="background:{{period color|Moscovian}}" |
| style="background:{{period color|Moscovian}}" |[[Moscovian (Carboniferous)|Moscovian]] |
||
|style="background:{{period color|Moscovian}}" |
| style="background:{{period color|Moscovian}}" |{{Period start|moscovian}} {{Period start error|moscovian}} |
||
|- |
|- |
||
|style="background:{{period color|Bashkirian}}" |
| style="background:{{period color|Bashkirian}}" |[[Bashkirian]] |
||
|style="background:{{period color|Bashkirian}}" |
| style="background:{{period color|Bashkirian}}" |{{Period start|bashkirian}} {{Period start error|bashkrian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="3" style="background:{{period color|Mississippian}}"|[[Mississippian (geology)|Mississippian]] |
| rowspan="3" style="background:{{period color|Mississippian}}" |[[Mississippian (geology)|Mississippian]]<br/>{{efn|group=note|name=MissiPenns}} |
||
|style="background:{{period color|Serpukhovian}}" |
| style="background:{{period color|Serpukhovian}}" |[[Serpukhovian]] |
||
|rowspan="3" |
| rowspan="3" |Large [[Lycopodiophyta|lycopodian primitive trees]] flourish and amphibious [[Eurypterid|eurypterids]] live amid [[coal]]-forming coastal [[Brackish water|swamps]], radiating significantly one last time. First [[gymnosperms]]. First [[Holometabola|holometabolous]], [[Paraneoptera|paraneopteran]], [[Polyneoptera|polyneopteran]], [[Odonatoptera|odonatopteran]] and [[Ephemeroptera|ephemeropteran]] insects and first [[barnacles]]. First five-digited [[tetrapods]] (amphibians) and [[land snails]]. In the oceans, [[Bony fish|bony]] and [[Chondrichthyes|cartilaginous fishes]] are dominant and diverse; [[Echinoderm|echinoderms]] (especially [[Crinoid|crinoids]] and [[Blastoid|blastoids]]) abundant. [[Coral|Corals]], [[Bryozoa|bryozoans]], [[Orthocerida|orthoceridans]], [[Goniatite|goniatites]] and brachiopods ([[Productida]], [[Spiriferida]], etc.) recover and become very common again, but [[Trilobita|trilobites]] and [[Nautiloid|nautiloids]] decline. [[Karoo Ice Age|Glaciation]] in East [[Gondwana]] continues from Late Devonian. [[Mayor Island/Tuhua|Tuhua Orogeny]] in New Zealand tapers off. Some lobe finned fish called rhizodonts become abundant and dominant in freshwaters. [[Siberia (continent)|Siberia]] collides with a different small continent, [[Kazakhstania]]. |
||
|style="background:{{period color|Serpukhovian}}" |
| style="background:{{period color|Serpukhovian}}" |{{Period start|serpukhovian}} {{Period start error|serpukhovian}} |
||
|- |
|- |
||
|style="background:{{period color|visean}}" |
| style="background:{{period color|visean}}" |[[Viséan]] |
||
|style="background:{{period color|visean}}" |
| style="background:{{period color|visean}}" |{{Period start|visean}} {{Period start error|visean}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Tournaisian}}" |
| style="background:{{period color|Tournaisian}}" |[[Tournaisian]] |
||
|style="background:{{period color|Tournaisian}}" |
| style="background:{{period color|Tournaisian}}" |{{Period start|tournaisian}} {{Period start error|tournaisian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="7" style="background:{{period color|Devonian}}" |
| rowspan="7" style="background:{{period color|Devonian}}" |[[Devonian]] |
||
|rowspan="2" style="background:{{period color|Late Devonian}}" |
| rowspan="2" style="background:{{period color|Late Devonian}}" |[[Late Devonian|Upper/Late]] |
||
|style="background:{{period color|Famennian}}" |
| style="background:{{period color|Famennian}}" |[[Famennian]] |
||
|rowspan="7" |
| rowspan="7" |First [[Lycopodiopsida|lycopods]], [[ferns]], [[seed plants]] ([[seed ferns]], from earlier [[Progymnosperm|progymnosperms]]), first trees (the progymnosperm ''[[Archaeopteris]]''), and first [[Pterygota|winged insects]] (palaeoptera and neoptera). [[Strophomenida|Strophomenid]] and [[Atrypa|atrypid]] [[Brachiopod|brachiopods]], [[Rugosa|rugose]] and [[Tabulata|tabulate]] corals, and [[Crinoid|crinoids]] are all abundant in the oceans. First fully coiled cephalopods ([[Ammonoidea]] and [[Nautilida]], independently) with the former group very abundant (especially [[goniatites]]). Trilobites and ostracoderms decline, while jawed fishes ([[Placodermi|placoderms]], [[Sarcopterygii|lobe-finned]] and [[Actinopterygii|ray-finned]] [[Osteichthyes|bony fish]], and [[acanthodians]] and early [[Chondrichthyes|cartilaginous fish]]) proliferate. Some [[Tetrapodomorpha|lobe finned fish]] transform into digited [[Stegocephalia|fishapods]], slowly becoming amphibious. The last non-trilobite artiopods die off. First [[decapods]] (like [[prawns]]) and [[isopods]]. Pressure from jawed fishes cause eurypterids to decline and [[Coleoidea|some cephalopods]] to lose their shells while anomalocarids vanish. "Old Red Continent" of [[Euramerica]] persists after forming in the Caledonian orogeny. Beginning of [[Acadian Orogeny]] for [[Atlas Mountains|Anti-Atlas Mountains]] of North Africa, and [[Appalachian Mountains]] of North America, also the [[Antler Orogeny|Antler]], [[Variscan Orogeny|Variscan]], and [[Mayor Island/Tuhua|Tuhua orogenies]] in New Zealand. A series of extinction events, including the massive [[Kellwasser event|Kellwasser]] and [[Hangenberg event|Hangenberg]] ones, wipe out many acritarchs, corals, sponges, molluscs, trilobites, eurypterids, graptolites, brachiopods, crinozoans (e.g. all [[cystoids]]), and fish, including all placoderms and ostracoderms. |
||
|style="background:{{period color|Famennian}}" |
| style="background:{{period color|Famennian}}" |{{Period start|famennian}} {{Period start error|famennian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Frasnian}}" |
| style="background:{{period color|Frasnian}}" |[[Frasnian]] |
||
|style="background:{{period color|Frasnian}}" |
| style="background:{{period color|Frasnian}}" |{{Period start|frasnian}} {{Period start error|frasnian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Middle Devonian}}" |
| rowspan="2" style="background:{{period color|Middle Devonian}}" |[[Middle Devonian|Middle]] |
||
|style="background:{{period color|Givetian}}" |
| style="background:{{period color|Givetian}}" |[[Givetian]] |
||
|style="background:{{period color|Givetian}}" |
| style="background:{{period color|Givetian}}" |{{Period start|givetian}} {{Period start error|givetian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Eifelian}}" |
| style="background:{{period color|Eifelian}}" |[[Eifelian]] |
||
|style="background:{{period color|Eifelian}}" |
| style="background:{{period color|Eifelian}}" |{{Period start|eifelian}} {{Period start error|eifelian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="3" style="background:{{period color|Early Devonian}}" |
| rowspan="3" style="background:{{period color|Early Devonian}}" |[[Early Devonian|Lower/Early]] |
||
|style="background:{{period color|Emsian}}" |
| style="background:{{period color|Emsian}}" |[[Emsian]] |
||
|style="background:{{period color|Emsian}}" |
| style="background:{{period color|Emsian}}" |{{Period start|emsian}} {{Period start error|emsian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Pragian}}" |
| style="background:{{period color|Pragian}}" |[[Pragian]] |
||
|style="background:{{period color|Pragian}}" |
| style="background:{{period color|Pragian}}" |{{Period start|pragian}} {{Period start error|pragian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Lochkovian}}" |
| style="background:{{period color|Lochkovian}}" |[[Lochkovian]] |
||
|style="background:{{period color|Lochkovian}}" |
| style="background:{{period color|Lochkovian}}" |{{Period start|lochkovian}} {{Period start error|lochkovian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="8" style="background:{{period color|Silurian}}" |
| rowspan="8" style="background:{{period color|Silurian}}" |[[Silurian]] |
||
|colspan="2" style="background:{{period color|Pridoli}}" |
| colspan="2" style="background:{{period color|Pridoli}}" |[[Pridoli epoch|Pridoli]] |
||
|rowspan="8" |
| rowspan="8" |[[Ozone layer]] thickens. First [[Vascular plant|vascular plants]] and fully terrestrialized arthropods: [[myriapods]], [[Hexapoda|hexapods]] (including [[insects]]), and [[arachnids]]. [[Eurypterid|Eurypterids]] diversify rapidly, becoming widespread and dominant. Cephalopods continue to flourish. True [[Jawed fish|jawed fishes]], along with [[Ostracoderm|ostracoderms]], also roam the seas. [[Tabulate coral|Tabulate]] and [[Rugosa|rugose]] corals, [[Brachiopod|brachiopods]] (''Pentamerida'', [[Rhynchonellida]], etc.), [[cystoids]] and [[Crinoid|crinoids]] all abundant. [[Trilobite|Trilobites]] and [[Mollusc|molluscs]] diverse; [[Graptolite|graptolites]] not as varied. Three minor extinction events. Some echinoderms go extinct. Beginning of [[Caledonian Orogeny]] (collision between Laurentia, Baltica and one of the formerly small Gondwanan terranes) for hills in England, Ireland, Wales, Scotland, and the [[Scandinavian Mountains]]. Also continued into Devonian period as the [[Acadian Orogeny]], above (thus Euramerica forms). [[Taconic Orogeny]] tapers off. [[Andean-Saharan glaciation|Icehouse period]] ends late in this period after starting in Late Ordovician. [[Lachlan Orogeny]] on [[Australia (continent)|Australian continent]] tapers off. |
||
|style="background:{{period color|Pridoli}}" |
| style="background:{{period color|Pridoli}}" |{{Period start|pridoli}} {{Period start error|pridoli}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Ludlow}}" |
| rowspan="2" style="background:{{period color|Ludlow}}" |[[Ludlow epoch|Ludlow]] |
||
|style="background:{{period color|Ludfordian}}" |
| style="background:{{period color|Ludfordian}}" |[[Ludfordian]] |
||
|style="background:{{period color|Ludfordian}}" |
| style="background:{{period color|Ludfordian}}" |{{Period start|ludfordian}} {{Period start error|ludfordian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Gorstian}}" |
| style="background:{{period color|Gorstian}}" |[[Gorstian]] |
||
|style="background:{{period color|Gorstian}}" |
| style="background:{{period color|Gorstian}}" |{{Period start|gorstian}} {{Period start error|gorstian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Wenlock}}" |
| rowspan="2" style="background:{{period color|Wenlock}}" |[[Wenlock epoch|Wenlock]] |
||
|style="background:{{period color|Homerian}}" |
| style="background:{{period color|Homerian}}" |[[Homerian]] |
||
|style="background:{{period color|Homerian}}" |
| style="background:{{period color|Homerian}}" |{{Period start|homerian}} {{Period start error|homerian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Sheinwoodian}}" |
| style="background:{{period color|Sheinwoodian}}" |[[Sheinwoodian]] |
||
|style="background:{{period color|Sheinwoodian}}" |
| style="background:{{period color|Sheinwoodian}}" |{{Period start|sheinwoodian}} {{Period start error|sheinwoodian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="3" style="background:{{period color|Llandovery}}" |
| rowspan="3" style="background:{{period color|Llandovery}}" |[[Llandovery epoch|Llandovery]] |
||
|style="background:{{period color|Telychian}}" |
| style="background:{{period color|Telychian}}" |[[Telychian]] |
||
|style="background:{{period color|Telychian}}" |
| style="background:{{period color|Telychian}}" |{{Period start|telychian}} {{Period start error|telychian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Aeronian}}" |
| style="background:{{period color|Aeronian}}" |[[Aeronian]] |
||
|style="background:{{period color|Aeronian}}" |
| style="background:{{period color|Aeronian}}" |{{Period start|aeronian}} {{Period start error|aeronian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Rhuddanian}}" |
| style="background:{{period color|Rhuddanian}}" |[[Rhuddanian]] |
||
|style="background:{{period color|Rhuddanian}}" |
| style="background:{{period color|Rhuddanian}}" |{{Period start|rhuddanian}} {{Period start error|rhuddanian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="7" style="background:{{period color|Ordovician}}" |
| rowspan="7" style="background:{{period color|Ordovician}}" |[[Ordovician]] |
||
|rowspan="3" style="background:{{period color|Late Ordovician}}" |
| rowspan="3" style="background:{{period color|Late Ordovician}}" |[[Late Ordovician|Upper/Late]] |
||
|style="background:{{period color|Hirnantian}}" |
| style="background:{{period color|Hirnantian}}" |[[Hirnantian]] |
||
|rowspan="7" |
| rowspan="7" |The [[Great Ordovician Biodiversification Event]] occurs as plankton increase in number: [[Invertebrate|invertebrates]] diversify into many new types (especially brachiopods and molluscs; e.g. long [[Orthoconic|straight-shelled]] cephalopods like the long lasting and diverse [[Orthocerida]]). Early [[Coral|corals]], articulate [[Brachiopod|brachiopods]] (''Orthida'', ''Strophomenida'', etc.), [[bivalves]], [[Cephalopod|cephalopods]] (nautiloids), [[Trilobite|trilobites]], [[Ostracod|ostracods]], [[Bryozoa|bryozoans]], many types of [[echinoderms]] ([[blastoids]], [[cystoids]], [[crinoids]], [[sea urchins]], [[sea cucumbers]], and [[Asterozoa|star-like forms]], etc.), branched [[Graptolite|graptolites]], and other taxa all common. [[Acritarch|Acritarchs]] still persist and common. Cephalopods become dominant and common, with some trending toward a coiled shell. Anomalocarids decline. Mysterious [[Tentaculita|tentaculitans]] appear. First [[eurypterids]] and [[ostracoderm]] fish appear, the latter probably giving rise to the [[jawed fish]] at the end of the period. First uncontroversial terrestrial [[fungi]] and fully terrestrialized [[Embryophytes|plants]]. [[Late Ordovician glaciation|Ice age]] at the end of this period, as well as a series of mass [[Late Ordovician mass extinction|extinction events]], killing off some cephalopods and many brachiopods, bryozoans, echinoderms, graptolites, trilobites, bivalves, corals and [[conodonts]]. |
||
|style="background:{{period color|Hirnantian}}"| {{Period start|hirnantian}} |
| style="background:{{period color|Hirnantian}}" |{{Period start|hirnantian}} {{Period start error|hirnantian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Katian}}" |
| style="background:{{period color|Katian}}" |[[Katian]] |
||
|style="background:{{period color|Katian}}"| {{Period start|katian}} |
| style="background:{{period color|Katian}}" |{{Period start|katian}} {{Period start error|katian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Sandbian}}" |
| style="background:{{period color|Sandbian}}" |[[Sandbian]] |
||
|style="background:{{period color|Sandbian}}"| {{Period start|sandbian}} |
| style="background:{{period color|Sandbian}}" |{{Period start|sandbian}} {{Period start error|sandbian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Middle Ordovician}}" |
| rowspan="2" style="background:{{period color|Middle Ordovician}}" |[[Middle Ordovician|Middle]] |
||
|style="background:{{period color|Darriwilian}}" |
| style="background:{{period color|Darriwilian}}" |[[Darriwilian]] |
||
|style="background:{{period color|Darriwilian}}"| {{Period start|darriwilian}} |
| style="background:{{period color|Darriwilian}}" |{{Period start|darriwilian}} {{Period start error|darriwilian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Dapingian}}" |
| style="background:{{period color|Dapingian}}" |[[Dapingian]] |
||
|style="background:{{period color|Dapingian}}"| {{Period start|dapingian}} |
| style="background:{{period color|Dapingian}}" |{{Period start|dapingian}} {{Period start error|dapingian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Early Ordovician}}" |
| rowspan="2" style="background:{{period color|Early Ordovician}}" |[[Early Ordovician|Lower/Early]] |
||
|style="background:{{period color|Floian}}" |
| style="background:{{period color|Floian}}" |[[Floian]]<br />(formerly [[Arenig]]) |
||
|style="background:{{period color|Floian}}"| {{Period start|floian}} |
| style="background:{{period color|Floian}}" |{{Period start|floian}} {{Period start error|floian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Tremadocian}}" |
| style="background:{{period color|Tremadocian}}" |[[Tremadocian]] |
||
|style="background:{{period color|Tremadocian}}"| {{Period start|tremadocian}} |
| style="background:{{period color|Tremadocian}}" |{{Period start|tremadocian}} {{Period start error|tremadocian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="10" style="background:{{period color|Cambrian}}" |
| rowspan="10" style="background:{{period color|Cambrian}}" |[[Cambrian]] |
||
|rowspan="3" style="background:{{period color|Furongian}}" |
| rowspan="3" style="background:{{period color|Furongian}}" |[[Furongian]] |
||
|style="background:{{period color|Stage 10}}" |
| style="background:{{period color|Stage 10}}" |[[Cambrian Stage 10|Stage 10]] |
||
|rowspan="10" |
| rowspan="10" |Major diversification of (fossils mainly show bilaterian) life in the [[Cambrian Explosion]] as oxygen levels increase. Numerous fossils; most modern [[animal]] [[Phylum|phyla]] (including [[arthropods]], [[molluscs]], [[annelids]], [[echinoderms]], [[hemichordates]] and [[chordates]]) appear. Reef-building [[Archaeocyatha|archaeocyathan]] sponges initially abundant, then vanish. Stromatolites replace them, but quickly fall prey to the [[Agronomic revolution]], when some animals started burrowing through the microbial mats (affecting some other animals as well). First [[artiopods]] (including [[trilobites]]), [[priapulid]] worms, inarticulate [[Brachiopod|brachiopods]] (unhinged lampshells), [[hyoliths]], [[Bryozoa|bryozoans]], [[graptolites]], pentaradial echinoderms (e.g. [[Blastozoa|blastozoans]], [[Crinozoa|crinozoans]] and [[Eleutherozoa|eleutherozoans]]), and numerous other animals. [[Anomalocarid|Anomalocarids]] are dominant and giant predators, while [[End-Ediacaran extinction|many Ediacaran fauna die out]]. [[Crustacea|Crustaceans]] and molluscs diversify rapidly. [[Prokaryote|Prokaryotes]], [[Protist|protists]] (e.g., [[Foram|forams]]), [[algae]] and [[fungi]] continue to present day. First [[vertebrates]] from earlier chordates. [[Petermann Orogeny]] on the [[Australia (continent)|Australian continent]] tapers off (550–535 Ma). Ross Orogeny in Antarctica. [[Delamerian Orogeny]] (c. 514–490 Ma) on [[Australia (continent)|Australian continent]]. Some small terranes split off from Gondwana. [[Atmosphere of Earth|Atmospheric]] {{CO2}} content roughly 15 times present-day ([[Holocene]]) levels (6000 ppm compared to today's 400 ppm)<ref name="Royer_2006" />{{efn|name="atmospheric-carbon-dioxide"|group=note}} [[Arthropods]] and [[Embryophytes|streptophyta]] start colonizing land. 3 extinction events occur 517, 502 & 488 Ma, the [[End-Botomian mass extinction|first]] and [[Cambrian–Ordovician extinction event|last]] of which wipe out many of the anomalocarids, artiopods, hyoliths, brachiopods, molluscs, and conodonts (early jawless vertebrates). |
||
|style="background:{{period color|Stage 10}}" |
| style="background:{{period color|Stage 10}}" |~489.5 |
||
|- |
|- |
||
|style="background:{{period color|Jiangshanian}}" |
| style="background:{{period color|Jiangshanian}}" |[[Jiangshanian]] |
||
|style="background:{{period color|Jiangshanian}}" |
| style="background:{{period color|Jiangshanian}}" |~{{Period start|Jiangshanian}} {{Period start error|Jiangshanian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Paibian}}" |
| style="background:{{period color|Paibian}}" |[[Paibian]] |
||
|style="background:{{period color|Paibian}}" |
| style="background:{{period color|Paibian}}" |~{{Period start|paibian}} {{Period start error|paibian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan="3" style="background:{{period color|Series 3}}" |
| rowspan="3" style="background:{{period color|Series 3}}" |[[Miaolingian]] |
||
|style="background:{{period color|Guzhangian}}" |
| style="background:{{period color|Guzhangian}}" |[[Guzhangian]] |
||
|style="background:{{period color|Guzhangian}}" |
| style="background:{{period color|Guzhangian}}" |~{{Period start|guzhangian}} {{Period start error|guzhangian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Drumian}}" |
| style="background:{{period color|Drumian}}" |[[Drumian]] |
||
|style="background:{{period color|Drumian}}" |
| style="background:{{period color|Drumian}}" |~{{Period start|drumian}} {{Period start error|drumian}}<sup>*</sup> |
||
|- |
|- |
||
|style="background:{{period color|Stage 5}}" |
| style="background:{{period color|Stage 5}}" |[[Wuliuan]] |
||
|style="background:{{period color|Stage 5}}" |
| style="background:{{period color|Stage 5}}" |~{{Period start|wuliuan}} {{Period start error|wuliuan}} |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Series 2}}" |
| rowspan="2" style="background:{{period color|Series 2}}" |[[Cambrian Series 2|Series 2]] |
||
|style="background:{{period color|Stage 4}}" |
| style="background:{{period color|Stage 4}}" |[[Cambrian Stage 4|Stage 4]] |
||
|style="background:{{period color|Stage 4}}" |
| style="background:{{period color|Stage 4}}" |~{{Period start|cambrian stage 4}} {{Period start error|cambrian stage 4}} |
||
|- |
|- |
||
|style="background:{{period color|Stage 3}}" |
| style="background:{{period color|Stage 3}}" |[[Cambrian Stage 3|Stage 3]] |
||
|style="background:{{period color|Stage 3}}" |
| style="background:{{period color|Stage 3}}" |~{{Period start|cambrian stage 3}} {{Period start error|cambrian stage 3}} |
||
|- |
|- |
||
|rowspan="2" style="background:{{period color|Terreneuvian}}" |
| rowspan="2" style="background:{{period color|Terreneuvian}}" |[[Terreneuvian]] |
||
|style="background:{{period color|Stage 2}}" |
| style="background:{{period color|Stage 2}}" |[[Cambrian Stage 2|Stage 2]] |
||
|style="background:{{period color|Stage 2}}" |
| style="background:{{period color|Stage 2}}" |~{{Period start|cambrian stage 2}} {{Period start error|cambrian stage 2}} |
||
|- |
|- |
||
|style="background:{{period color|Fortunian}}" |
| style="background:{{period color|Fortunian}}" |[[Fortunian]] |
||
|style="background:{{period color|Fortunian}}" |
| style="background:{{period color|Fortunian}}" |~{{Period start|fortunian}} {{Period start error|fortunian}}<sup>*</sup> |
||
|- |
|- |
||
|rowspan=" |
| rowspan="10" style="background:{{period color|Proterozoic}}" |[[Proterozoic]] |
||
|rowspan=" |
| rowspan="3" style="background:{{period color|Neoproterozoic}}" |[[Neoproterozoic]] |
||
| |
| style="background:{{period color|Ediacaran}}" |[[Ediacaran]] |
||
| colspan="3" |Good [[Fossil|fossils]] of primitive [[Animal|animals]]. [[Ediacaran biota]] flourish worldwide in seas, possibly appearing after an [[Avalon explosion|explosion]], possibly caused by a large-scale oxidation event.<ref name="Williams_2019">{{Cite journal |last=Williams |first=Joshua J. |last2=Mills |first2=Benjamin J. W. |last3=Lenton |first3=Timothy M. |date=2019 |title=A tectonically driven Ediacaran oxygenation event |url=http://www.nature.com/articles/s41467-019-10286-x |journal=Nature Communications |language=en |volume=10 |issue=1 |pages=2690 |doi=10.1038/s41467-019-10286-x |issn=2041-1723 |pmc=PMC6584537 |pmid=31217418}}</ref> First [[Vendozoa|vendozoans]] (unknown affinity among animals), [[Cnidaria|cnidarians]] and [[Bilateria|bilaterians]]. Enigmatic vendozoans include many soft-jellied creatures shaped like bags, disks, or quilts (like ''[[Dickinsonia]]''). Simple [[Trace fossil|trace fossils]] of possible worm-like ''[[Trichophycus pedum|Trichophycus]]'', etc.[[Taconic Orogeny]] in North America. [[Aravalli Range]] [[orogeny]] in [[Indian subcontinent]]. Beginning of [[Pan-African Orogeny]], leading to the formation of the short-lived Ediacaran supercontinent [[Pannotia]], which by the end of the period breaks up into [[Laurentia]], [[Baltica]], [[Siberia (continent)|Siberia]] and [[Gondwana]]. [[Petermann Orogeny]] forms on [[Australia (continent)|Australian continent]]. Beardmore Orogeny in Antarctica, 633–620 Ma. [[Ozone layer]] forms. An increase in oceanic [[mineral]] levels. |
|||
|style="background:{{period color|Ediacaran}}"| [[Ediacaran]] |
|||
| style="background:{{period color|Ediacaran}}" |~{{Period start|ediacaran}} {{Period start error|ediacaran}}<sup>*</sup> |
|||
|colspan="3"| Good [[fossil]]s of primitive [[animal]]s. [[Ediacaran biota]] flourish worldwide in seas, possibly appearing after an [[Avalon explosion|explosion]], possibly caused by a large-scale oxidation event.<ref>Williams, J.J., Mills, B.J.W. & Lenton, T.M. A tectonically driven Ediacaran oxygenation event. Nat Commun 10, 2690 (2019). https://doi.org/10.1038/s41467-019-10286-x</ref> First [[vendozoa]]ns (unknown affinity among animals), [[cnidaria]]ns and [[bilateria]]ns. Enigmatic vendozoans include many soft-jellied creatures shaped like bags, disks, or quilts (like ''[[Dickinsonia]]''). Simple [[trace fossil]]s of possible worm-like ''[[Trichophycus pedum|Trichophycus]]'', etc.[[Taconic Orogeny]] in North America. [[Aravalli Range]] [[orogeny]] in [[Indian subcontinent]]. Beginning of [[Pan-African Orogeny]], leading to the formation of the short-lived Ediacaran supercontinent [[Pannotia]], which by the end of the period breaks up into [[Laurentia]], [[Baltica]], [[Siberia (continent)|Siberia]] and [[Gondwana]]. [[Petermann Orogeny]] forms on [[Australia (continent)|Australian continent]]. Beardmore Orogeny in Antarctica, 633–620 [[Year#SI prefix multipliers|Ma]]. [[Ozone layer]] forms. An increase in oceanic [[mineral]] levels. |
|||
|style="background:{{period color|Ediacaran}}"| ~{{Period start|ediacaran}}<sup>*</sup> |
|||
|- |
|- |
||
|style="background:{{period color|Cryogenian}}" |
| style="background:{{period color|Cryogenian}}" |[[Cryogenian]] |
||
|colspan="3" |
| colspan="3" |Possible "[[Snowball Earth]]" period. [[Fossil|Fossils]] still rare. Late Ruker / Nimrod Orogeny in Antarctica tapers off. First uncontroversial [[Sponge|animal]] fossils. First hypothetical [[Amastigomycota|terrestrial fungi]]<ref name="NaranjoOrtiz_2019">{{cite journal |last1=Naranjo‐Ortiz |first1=Miguel A. |last2=Gabaldón |first2=Toni |date=2019-04-25 |title=Fungal evolution: major ecological adaptations and evolutionary transitions |journal=[[Biological Reviews of the Cambridge Philosophical Society]] |publisher=[[Cambridge Philosophical Society]] ([[Wiley Publishing|Wiley]]) |volume=94 |issue=4 |pages=1443–1476 |doi=10.1111/brv.12510 |issn=1464-7931}}</ref> and [[streptophyta]].<ref name="Zarsky_2022">{{Cite journal |last=Žárský |first=Jakub |last2=Žárský |first2=Vojtěch |last3=Hanáček |first3=Martin |last4=Žárský |first4=Viktor |date=2022-01-27 |title=Cryogenian Glacial Habitats as a Plant Terrestrialisation Cradle – The Origin of the Anydrophytes and Zygnematophyceae Split |url=https://www.frontiersin.org/articles/10.3389/fpls.2021.735020/full |journal=Frontiers in Plant Science |volume=12 |pages=735020 |doi=10.3389/fpls.2021.735020 |issn=1664-462X |pmc=PMC8829067 |pmid=35154170}}</ref> |
||
|style="background:{{period color|Cryogenian}}" |
| style="background:{{period color|Cryogenian}}" |~{{Period start|cryogenian}} {{Period start error|cryogenian}}{{efn|name="absolute-age"|Defined by absolute age ([[Global Standard Stratigraphic Age]]).|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Tonian}}" |
| style="background:{{period color|Tonian}}" |[[Tonian]] |
||
|colspan="3"| [[Rodinia]] supercontinent |
| colspan="3" |Finall assembly of [[Rodinia]] supercontinent occurs in early Tonian, with breakup beginning c. 800 Ma. [[Sveconorwegian orogeny]] ends. [[Grenville Orogeny]] tapers off in North America. Lake Ruker / Nimrod Orogeny in Antarctica, 1,000 ± 150 Ma. Edmundian Orogeny (c. 920–850 Ma), [[Gascoyne Complex]], Western Australia. Deposition of [[Adelaide Superbasin]] and [[Centralian Superbasin]] begins on [[Australia (continent)|Australian continent]]. First hypothetical [[animals]] (from holozoans) and terrestrial algal mats. Many endosymbiotic events concerning red and green algae occur, transferring plastids to [[ochrophyta]] (e.g. [[diatoms]], [[brown algae]]), [[dinoflagellates]], [[cryptophyta]], [[haptophyta]], and [[Euglenid|euglenids]] (the events may have begun in the Mesoproterozoic)<ref name="Yoon_2004">{{Cite journal |last=Yoon |first=Hwan Su |last2=Hackett |first2=Jeremiah D. |last3=Ciniglia |first3=Claudia |last4=Pinto |first4=Gabriele |last5=Bhattacharya |first5=Debashish |date=2004 |title=A Molecular Timeline for the Origin of Photosynthetic Eukaryotes |url=https://academic.oup.com/mbe/article-lookup/doi/10.1093/molbev/msh075 |journal=Molecular Biology and Evolution |language=en |volume=21 |issue=5 |pages=809–818 |doi=10.1093/molbev/msh075 |issn=1537-1719}}</ref> while the first [[Retaria|retarians]] (e.g. [[forams]]) also appear: eukaryotes diversify rapidly, including algal, eukaryovoric and [[Biomineralization|biomineralized]] forms. [[Trace fossil|Trace fossils]] of simple [[Multicellular|multi-celled]] eukaryotes. |
||
|style="background:{{period color|Tonian}}"| {{Period start|tonian}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Tonian}}" |{{Period start|tonian}} {{Period start error|tonian}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|rowspan="3" style="background:{{period color|Mesoproterozoic}}" |
| rowspan="3" style="background:{{period color|Mesoproterozoic}}" |[[Mesoproterozoic]] |
||
|style="background:{{period color|Stenian}}" |
| style="background:{{period color|Stenian}}" |[[Stenian]] |
||
|colspan="3" |
| colspan="3" |Narrow highly [[Metamorphic rock|metamorphic]] belts due to [[orogeny]] as [[Rodinia]] forms, surrounded by the [[Pan-African Ocean]]. [[Sveconorwegian orogeny]] starts. Late Ruker / Nimrod Orogeny in Antarctica possibly begins. Musgrave Orogeny (c. 1,080–), [[Musgrave Block]], [[Central Australia]]. [[Stromatolites]] decline as [[algae]] proliferate. |
||
|style="background:{{period color|Stenian}}"| {{Period start|stenian}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Stenian}}" |{{Period start|stenian}} {{Period start error|stenian}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Ectasian}}" |
| style="background:{{period color|Ectasian}}" |[[Ectasian]] |
||
|colspan="3" |
| colspan="3" |[[Platform cover|Platform covers]] continue to expand. [[Alga|Algal]] [[Colony (biology)|colonies]] in the seas. [[Grenville Orogeny]] in North America. Columbia breaks up. |
||
|style="background:{{period color|Ectasian}}"| {{Period start|ectasian}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Ectasian}}" |{{Period start|ectasian}} {{Period start error|ectasian}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Calymmian}}" |
| style="background:{{period color|Calymmian}}" |[[Calymmian]] |
||
|colspan="3" |
| colspan="3" |[[Platform cover|Platform covers]] expand. Barramundi Orogeny, [[McArthur Basin]], [[Northern Australia]], and Isan Orogeny, {{circa}} 1,600 Ma, Mount Isa Block, Queensland. First [[Archaeplastida|archaeplastidans]] (the first eukaryotes with [[plastids]] from cyanobacteria; e.g. [[Red algae|red]] and [[green algae]]) and [[opisthokonts]] (giving rise to the first [[fungi]] and [[Holozoa|holozoans]]). [[Acritarch|Acritarchs]] (remains of marine algae possibly) start appearing in the fossil record. |
||
|style="background:{{period color|Calymmian}}"| {{Period start|calymmian}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Calymmian}}" |{{Period start|calymmian}} {{Period start error|calymmian}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|rowspan="4" style="background:{{period color|Paleoproterozoic}}" |
| rowspan="4" style="background:{{period color|Paleoproterozoic}}" |[[Paleoproterozoic]] |
||
|style="background:{{period color|Statherian}}" |
| style="background:{{period color|Statherian}}" |[[Statherian]] |
||
|colspan="3" |
| colspan="3" |First uncontroversial [[eukaryotes]]: [[Protist|protists]] with nuclei and endomembrane system. [[Columbia (supercontinent)|Columbia]] forms as the second undisputed earliest supercontinent. Kimban Orogeny in Australian continent ends. Yapungku Orogeny on [[Yilgarn craton]], in Western Australia. Mangaroon Orogeny, 1,680–1,620 Ma, on the [[Gascoyne Complex]] in Western Australia. Kararan Orogeny (1,650 Ma), Gawler Craton, [[South Australia]]. Oxygen levels drop again. |
||
|style="background:{{period color|Statherian}}"| {{Period start|statherian}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Statherian}}" |{{Period start|statherian}} {{Period start error|statherian}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Orosirian}}" |
| style="background:{{period color|Orosirian}}" |[[Orosirian]] |
||
|colspan="3" |
| colspan="3" |The [[Atmosphere of Earth|atmosphere]] becomes much more [[Oxygen|oxygenic]] while more cyanobacterial stromatolites appear. [[Vredefort crater|Vredefort]] and [[Sudbury Basin]] asteroid impacts. Much [[orogeny]]. [[Penokean orogeny|Penokean]] and [[Trans-Hudsonian Orogeny|Trans-Hudsonian Orogenies]] in North America. Early Ruker Orogeny in Antarctica, 2,000–1,700 Ma. Glenburgh Orogeny, [[Gascoyne Complex|Glenburgh Terrane]], [[Australia (continent)|Australian continent]] {{circa}} 2,005–1,920 Ma. Kimban Orogeny, [[Gawler craton]] in Australian continent begins. |
||
|style="background:{{period color|Orosirian}}"| {{Period start|orosirian}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Orosirian}}" |{{Period start|orosirian}} {{Period start error|orosirian}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Rhyacian}}" |
| style="background:{{period color|Rhyacian}}" |[[Rhyacian]] |
||
|colspan="3" |
| colspan="3" |[[Bushveld Igneous Complex]] forms. [[Huronian]] glaciation. First hypothetical [[eukaryotes]]. Multicellular [[Francevillian biota]]. Kenorland disassembles. |
||
|style="background:{{period color|Rhyacian}}"| {{Period start|rhyacian}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Rhyacian}}" |{{Period start|rhyacian}} {{Period start error|rhyacian}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Siderian}}" |
| style="background:{{period color|Siderian}}" |[[Siderian]] |
||
|colspan="3" |
| colspan="3" |[[Great Oxidation Event]] (due to [[cyanobacteria]]) increases oxygen. Sleaford Orogeny on [[Australia (continent)|Australian continent]], [[Gawler Craton]] 2,440–2,420 Ma. |
||
|style="background:{{period color|Siderian}}"| {{Period start|siderian}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Siderian}}" |{{Period start|siderian}} {{Period start error|siderian}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|rowspan="4" style="background:{{period color|Archean}}" |
| rowspan="4" style="background:{{period color|Archean}}" |[[Archean]] |
||
|style="background:{{period color|Neoarchean}}"| |
| style="background:{{period color|Neoarchean}}" |[[Neoarchean]] |
||
|colspan="4" |
| colspan="4" |Stabilization of most modern [[Craton|cratons]]; possible [[Mantle (geology)|mantle]] overturn event. Insell Orogeny, 2,650 ± 150 Ma. [[Abitibi greenstone belt]] in present-day [[Ontario]] and [[Quebec]] begins to form, stabilizes by 2,600 Ma. First uncontroversial [[supercontinent]], [[Kenorland]], and first terrestrial [[prokaryotes]]. |
||
|style="background:{{period color|Neoarchean}}"| {{Period start|neoarchean}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Neoarchean}}" |{{Period start|neoarchean}} {{Period start error|neoarchean}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Mesoarchean}}"| |
| style="background:{{period color|Mesoarchean}}" |[[Mesoarchean]] |
||
|colspan="4" |
| colspan="4" |First [[Stromatolite|stromatolites]] (probably [[Colony (biology)|colonial]] phototrophic bacteria, like cyanobacteria). Oldest [[Macrofossil|macrofossils]]. Humboldt Orogeny in Antarctica. [[Blake River Megacaldera Complex]] begins to form in present-day [[Ontario]] and [[Quebec]], ends by roughly 2,696 Ma. |
||
|style="background:{{period color|Mesoarchean}}"| {{Period start|mesoarchean}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Mesoarchean}}" |{{Period start|mesoarchean}} {{Period start error|mesoarchean}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Paleoarchean}}"| |
| style="background:{{period color|Paleoarchean}}" |[[Paleoarchean]] |
||
|colspan="4" |
| colspan="4" |Prokaryotic [[archaea]] (e.g. [[methanogens]]) and [[bacteria]] (e.g. [[cyanobacteria]]) diversify rapidly, along with early [[viruses]]. First known [[Phototroph|phototrophic]] [[bacteria]]. Oldest definitive [[microfossils]]. First [[microbial mats]]. Oldest [[Craton|cratons]] on Earth (such as the [[Canadian Shield]] and the [[Pilbara Craton]]) may have formed during this period.{{efn|The age of the oldest measurable [[craton]], or [[continental crust]], is dated to 3,600–3,800 Ma.|name="Oldest-craton"|group=note}} Rayner Orogeny in Antarctica. |
||
|style="background:{{period color|Paleoarchean}}"| {{Period start|paleoarchean}}{{efn|name="absolute-age"}} |
| style="background:{{period color|Paleoarchean}}" |{{Period start|paleoarchean}} {{Period start error|paleoarchean}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
|style="background:{{period color|Eoarchean}}"| |
| style="background:{{period color|Eoarchean}}" |[[Eoarchean]] |
||
|colspan="4" |
| colspan="4" |First uncontroversial [[Life|living organisms]]: at first [[Protocell|protocells]] with [[RNA world|RNA-based genes]] around 4000 Ma, after which true [[Cell (biology)|cells]] ([[prokaryotes]]) evolve along with [[proteins]] and [[DNA]]-based genes around 3800 Ma. The end of the [[Late Heavy Bombardment]]. [[Napier Mountains|Napier]] Orogeny in Antarctica, 4,000 ± 200 Ma. |
||
|style="background:{{period color|Eoarchean}}"| |
| style="background:{{period color|Eoarchean}}" |{{Period start|eoarchean}} {{Period start error|eoarchean}}{{efn|name="absolute-age"|group=note}} |
||
|- |
|- |
||
| style="background:{{period color|Hadean}}" |[[Hadean]]<br/>{{efn|name="Hadean"|Though commonly used, the [[Hadean]] is not formally ratified by the ICS.|group=note}} |
|||
|rowspan="4" style="background:{{period color|Hadean}}"| [[Hadean]]{{efn|name="Precambrian-Time"}}{{efn|name="hadeon-not-formal"|Though commonly used, the [[Hadean]] is not a formal eon<ref name="OggEtAl2016">{{cite book | title=A Concise Geologic Time Scale: 2016 | publisher=Elsevier | first1=J.G. | last1=Ogg | first2=G. | last2=Ogg | first3=F.M. | last3=Gradstein | year=2016 | pages=20 | isbn=978-0-444-63771-0}}</ref> and no lower bound for the Archean and Eoarchean have been agreed upon. The Hadean has also sometimes been called the Priscoan or the Azoic. Sometimes, the Hadean can be found to be subdivided according to the [[lunar geologic timescale]]. These eras include the [[Cryptic era|Cryptic]] and [[Basin Groups]] (which are subdivisions of the [[Pre-Nectarian]] era), [[Nectarian]], and [[Early Imbrian]] units.}} |
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| colspan="5" |Formation of [[Protolith|protolith]] of the oldest known rock ([[Acasta Gneiss]]) c. 4,031 to 3,580 Ma.<ref name="Bowring_1999">{{cite journal |last1=Bowring |first1=Samuel A. |last2=Williams |first2=Ian S. |year=1999 |title=Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada |journal=Contributions to Mineralogy and Petrology |volume=134 |issue=1 |pages=3 |bibcode=1999CoMP..134....3B |doi=10.1007/s004100050465 |s2cid=128376754}}</ref><ref name="Iizuka_2007">{{Citation |last=Iizuka |first=Tsuyoshi |title=Chapter 3.1 The Early Archean Acasta Gneiss Complex: Geological, Geochronological and Isotopic Studies and Implications for Early Crustal Evolution |date=2007 |url=https://linkinghub.elsevier.com/retrieve/pii/S0166263507150313 |work=Developments in Precambrian Geology |volume=15 |pages=127–147 |publisher=Elsevier |language=en |doi=10.1016/s0166-2635(07)15031-3 |isbn=978-0-444-52810-0 |access-date=2022-05-01 |last2=Komiya |first2=Tsuyoshi |last3=Maruyama |first3=Shigenori}}</ref> Possible first appearance of [[Plate tectonic|plate tectonics]]. First hypothetical [[Abiogenesis|life forms]]. End of the Early Bombardment Phase. Oldest known [[mineral]] ([[Zircon]], 4,404 ± 8 Ma).<ref name="Wilde_2001">{{Cite journal |last1=Wilde |first1=Simon A. |last2=Valley |first2=John W. |last3=Peck |first3=William H. |last4=Graham |first4=Colin M. |date=2001 |title=Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago |url=http://www.nature.com/articles/35051550 |journal=Nature |language=en |volume=409 |issue=6817 |pages=175–178 |doi=10.1038/35051550 |issn=0028-0836 |pmid=11196637 |s2cid=4319774}}</ref> Asteroids and comets bring water to Earth, forming the first oceans. Formation of [[Moon]] (4,533 to 4,527 Ma), probably from a [[Giant impact hypothesis|giant impact]]. Formation of Earth (4,570 to 4,567.17 Ma) |
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|style="background:{{period color|Hadean}}"| [[Early Imbrian]] ([[Neohadean]]) (unofficial){{efn|name="Precambrian-Time"}}{{efn|name="Lunar-geologic-timescale-names"|These unit names were taken from the [[lunar geologic timescale]] and refer to geologic events that did not occur on Earth. Their use for Earth geology is unofficial. Note that their start times do not dovetail perfectly with the later, terrestrially defined boundaries.}} |
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| style="background:{{period color|Hadean}}" |~{{Period start|hadean}} {{Period start error|hadean}}{{efn|name="absolute-age"|group=note}} |
|||
|colspan="4"| This era overlaps the beginning of the [[Late Heavy Bombardment]] of the [[Inner Solar System|Inner]] [[Solar System]], produced possibly by the planetary migration of [[Neptune]] into the [[Kuiper belt]] as a result of orbital resonances between [[Jupiter]] and [[Saturn]]. Oldest known rock (4,031 to 3,580 [[Year#SI prefix multipliers|Ma]]).<ref name="Oldest-rock">{{cite journal|doi=10.1007/s004100050465|title=Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada|year=1999|last1=Bowring|first1=Samuel A.|journal=Contributions to Mineralogy and Petrology|volume=134|issue=1|pages=3|last2=Williams|first2=Ian S.|bibcode=1999CoMP..134....3B|s2cid=128376754}} The oldest rock on Earth is the [[Acasta Gneiss]], and it dates to 4.03 Ga, located in the [[Northwest Territories]] of Canada.</ref> |
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|style="background:{{period color|Hadean}}"| 4130<ref name="goldblatt2010" /> |
|||
|- |
|||
|style="background:{{period color|Hadean}}"| [[Nectarian]] ([[Mesohadean]]) (unofficial){{efn|name="Precambrian-Time"}}{{efn|name="Lunar-geologic-timescale-names"}} |
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|colspan="4"| Possible first appearance of [[plate tectonic]]s. This unit gets its name from the [[lunar geologic timescale]] when the [[Nectaris Basin]] and other greater [[lunar basin]]s form by big [[impact event]]s. First hypothetical [[abiogenesis|life forms]]. |
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|style="background:{{period color|Hadean}}"| 4280<ref name="goldblatt2010" /> |
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|- |
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|style="background:{{period color|Hadean}}"| [[Basin Groups]] ([[Paleohadean]]) (unofficial){{efn|name="Precambrian-Time"}}{{efn| name="Lunar-geologic-timescale-names"}} |
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|colspan="4"|End of the Early Bombardment Phase. Oldest known [[mineral]] ([[Zircon]], 4,404 ± 8 [[Year#SI prefix multipliers|Ma]]).<ref>{{Cite journal|last1=Wilde|first1=Simon A.|last2=Valley|first2=John W.|last3=Peck|first3=William H.|last4=Graham|first4=Colin M.|date=2001|title=Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago|url=http://www.nature.com/articles/35051550|journal=Nature|language=en|volume=409|issue=6817|pages=175–178|doi=10.1038/35051550|pmid=11196637|s2cid=4319774|issn=0028-0836}}</ref> Asteroids and comets bring water to Earth, forming the first oceans.<ref name="geology-wisc-edu">{{Cite web|url=http://www.geology.wisc.edu/%7Evalley/zircons/Wilde2001Nature.pdf|title=Geology.wisc.edu}}</ref> |
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|style="background:{{period color|Hadean}}"| 4533<ref name="goldblatt2010" /> |
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|- |
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|style="background:{{period color|Hadean}}"| [[Cryptic era|Cryptic]] ([[Cryptic era|Eohadean]]) (unofficial){{efn|name="Precambrian-Time"}}{{efn|name="Lunar-geologic-timescale-names"}} |
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|colspan="4"| Formation of [[Moon]] (4,533 to 4,527 [[Year#SI prefix multipliers|Ma]]), probably from [[Giant impact hypothesis|giant impact]], since the end of this era. Formation of Earth (4,570 to 4,567.17 [[Year#SI prefix multipliers|Ma]]), Early Bombardment Phase begins. Formation of [[Sun]] (4,680 to 4,630 [[Year#SI prefix multipliers|Ma]])<!--(Before the Hadean eon)-->. |
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|style="background:{{period color|Hadean}}"| {{Period start|hadean}} |
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|} |
|} |
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== Non-Earth based geologic time scales == |
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==Proposed Precambrian timeline== |
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{{Main|Lunar geologic timescale|Martian geologic timescale|Geology of Venus}}Some other [[Planet#Solar System|planets]] and [[Natural satellite|satellites]] in the [[Solar System]] have sufficiently rigid structures to have preserved records of their own histories, for example, [[Geology of Venus|Venus]], [[Geology of Mars|Mars]] and the Earth's [[Moon]]. Dominantly fluid planets, such as the [[gas giant]]s, do not comparably preserve their history. Apart from the [[Late Heavy Bombardment]], events on other planets probably had little direct influence on the Earth, and events on Earth had correspondingly little effect on those planets. Construction of a time scale that links the planets is, therefore, of only limited relevance to the Earth's time scale, except in a Solar System context. The existence, timing, and terrestrial effects of the Late Heavy Bombardment are still a matter of debate.{{efn|Not enough is known about extra-solar planets for worthwhile speculation.|group=note}} |
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The ICS's ''Geologic Time Scale 2012'' book which includes the new approved time scale also displays a proposal to substantially revise the Precambrian time scale to reflect important events such as the [[formation of the Earth]] or the [[Great Oxidation Event]], among others, while at the same time maintaining most of the previous chronostratigraphic nomenclature for the pertinent time span.<ref name="vankranendonk2012">{{cite book|last=Van Kranendonk|first=Martin J. |title=The geologic time scale 2012|date=2012|publisher=Elsevier|location=Amsterdam|isbn=978-0-44-459425-9|pages=359–365|edition=1st|editor=Felix M. Gradstein |editor2=James G. Ogg |editor3=Mark D. Schmitz |editor4=abi M. Ogg|chapter=16: A Chronostratigraphic Division of the Precambrian: Possibilities and Challenges|doi=10.1016/B978-0-444-59425-9.00016-0}}</ref> (See also [[Period (geology)#Structure]].) |
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=== Lunar (selenological) time scale === |
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*[[Hadean]] Eon – 4567–4030 Ma |
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The [[Geology of the Moon|geologic history]] of Earth's Moon has been divided into a time scale based on [[Geomorphology|geomorphological]] markers, namely [[Impact crater|impact cratering]], [[volcanism]], and [[erosion]]. This process of dividing the Moon's history in this manner means that the time scale boundaries do not imply fundamental changes in geological processes, unlike Earth's geologic time scale. Five geologic systems/periods ([[Pre-Nectarian]], [[Nectarian]], [[Imbrian]], [[Eratosthenian]], [[Copernican period|Copernican]]), with the Imbrian divided into two series/epochs (Early and Late) were defined in the latest Lunar geologic time scale.<ref name="Wilhelms_1987">{{Cite book |last=Wilhelms |first=Don E. |title=The Geologic History of the Moon |publisher=United States Geological Survey |year=1987 |doi=10.3133/pp1348}}</ref> The Moon is unique in the Solar System that is the only other body which we have rock samples with a known geological context. |
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**[[Chaotian (geology)|Chaotian]] Era – 4567–4404 Ma – the name alluding both to the [[Chaos (cosmogony)|mythological Chaos]] and the [[Chaos theory|chaotic]] phase of [[planet formation]]<ref name="vankranendonk2012" /><ref name="goldblatt2010">{{cite journal|last1=Goldblatt|first1=C.|first2=K. J.|last2=Zahnle |first3=N. H.|last3=Sleep |first4=E. G.|last4=Nisbet |title=The Eons of Chaos and Hades|journal=Solid Earth|date=2010|volume=1|issue=1|pages=1–3|bibcode = 2010SolE....1....1G |doi=10.5194/se-1-1-2010|doi-access=free}}</ref><ref>{{cite journal|last=Chambers|first=John E.|title=Planetary accretion in the inner Solar System|journal=Earth and Planetary Science Letters|date=July 2004|volume=223|issue=3–4|pages=241–252|doi=10.1016/j.epsl.2004.04.031|url=http://www.astro.washington.edu/courses/astro321/Chambers_EPSL_04.pdf|bibcode = 2004E&PSL.223..241C }}</ref> |
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{{Timeline Lunar Geological Timescale}} |
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**Jack Hillsian or Zirconian Era – 4404–4030 Ma – both names allude to the Jack Hills Greenstone Belt which provided the oldest mineral grains on Earth, [[zircons]]<ref name="vankranendonk2012" /><ref name=goldblatt2010 /> |
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*[[Archean]] Eon – 4030–2420 Ma |
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**[[Paleoarchean]] Era – 4030–3490 Ma |
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***[[Acastan]] Period – 4030–3810 Ma – named after the [[Acasta Gneiss]]<ref name="vankranendonk2012" /><ref name=goldblatt2010 /> |
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***[[Isuan]] Period – 3810–3490 Ma – named after the [[Isua Greenstone Belt]]<ref name="vankranendonk2012" /> |
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**[[Mesoarchean]] Era – 3490–2780 Ma |
|||
***[[Vaalbaran]] Period – 3490–3020 Ma – based on the names of the [[Kapvaal craton|Kapvaal]] (Southern Africa) and [[Pilbara Craton|Pilbara]] (Western Australia) [[craton]]s<ref name="vankranendonk2012" /> |
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***[[Pongolan]] Period – 3020–2780 Ma – named after the Pongola Supergroup<ref name="vankranendonk2012" /> |
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**[[Neoarchean]] Era – 2780–2420 Ma |
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***[[Methanian]] Period – 2780–2630 Ma – named for the inferred predominance of [[methanotrophic]] [[prokaryotes]]<ref name="vankranendonk2012" /> |
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***[[Siderian]] Period – 2630–2420 Ma – named for the voluminous banded iron formations formed within its duration<ref name="vankranendonk2012" /> |
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*[[Proterozoic]] Eon – 2420–541 Ma |
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**[[Paleoproterozoic]] Era – 2420–1780 Ma |
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***[[Oxygenian]] Period – 2420–2250 Ma – named for displaying the first evidence for a global oxidizing atmosphere<ref name="vankranendonk2012" /> |
|||
***[[Rhyacian|Jatulian or Eukaryian]] Period – 2250–2060 Ma – names are respectively for the Lomagundi–Jatuli δ<sup>13</sup>C isotopic excursion event spanning its duration, and for the (proposed)<ref name="El Albani et al 2014">{{cite journal|last1=El Albani|first1=Abderrazak|last2=Bengtson|first2=Stefan|last3=Canfield|first3=Donald E.|last4=Riboulleau|first4=Armelle|last5=Rollion Bard|first5=Claire|last6=Macchiarelli|first6=Roberto|display-authors=etal|title=The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity|journal=PLOS ONE|year= 2014|volume=9|issue=6|pages=e99438|doi=10.1371/journal.pone.0099438|bibcode = 2014PLoSO...999438E|pmid=24963687|pmc=4070892|doi-access=free}}</ref><ref name="Albani2010">{{cite journal|last1=El Albani|first1=Abderrazak|last2=Bengtson|first2=Stefan|last3=Canfield|first3=Donald E.|last4=Bekker|first4=Andrey|last5=Macchiarelli|first5=Roberto|last6=Mazurier|first6=Arnaud|last7=Hammarlund|first7=Emma U.|display-authors=etal|title=Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago|journal=Nature|year=2010|volume=466|issue=7302|pages=100–104|doi=10.1038/nature09166|pmid=20596019|url=http://www.afrikibouge.com/publications/Article%20Albani.pdf|bibcode=2010Natur.466..100A|s2cid=4331375}}{{Dead link|date=February 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> first fossil appearance of [[Eukaryota|eukaryotes]]<ref name="vankranendonk2012" /> |
|||
***[[Columbian Period]] – 2060–1780 Ma – named after the supercontinent [[Columbia (supercontinent)|Columbia]]<ref name="vankranendonk2012" /> |
|||
**[[Mesoproterozoic]] Era – 1780–850 Ma |
|||
***[[Rodinian]] Period – 1780–850 Ma – named after the supercontinent [[Rodinia]], stable environment<ref name="vankranendonk2012" /> |
|||
**[[Neoproterozoic]] Era – 850–541 Ma |
|||
***[[Cryogenian]] Period – 850–630 Ma – named for the occurrence of several glaciations<ref name="vankranendonk2012" /> |
|||
***[[Ediacaran]] Period – 630–541 Ma |
|||
Shown to scale: |
|||
=== Martian geologic time scale === |
|||
The [[geological history of Mars]] has been divided into two alternate time scales. The first time scale for Mars was developed by studying the impact crater densities on the Martian surface. Through this method four periods have been defined, the Pre-Noachian (~4,500–4,100 Ma), Noachian (~4,100–3,700 Ma), Hesperian (~3,700–3,000 Ma), and Amazonian (~3,000 Ma to present).<ref name="Tanaka_1986">{{Cite journal |last=Tanaka |first=Kenneth L. |date=1986 |title=The stratigraphy of Mars |url=http://doi.wiley.com/10.1029/JB091iB13p0E139 |journal=Journal of Geophysical Research |language=en |volume=91 |issue=B13 |pages=E139 |doi=10.1029/JB091iB13p0E139 |issn=0148-0227}}</ref><ref name="Carr_2010">{{Cite journal |last=Carr |first=Michael H. |last2=Head |first2=James W. |date=2010-06-01 |title=Geologic history of Mars |url=https://www.sciencedirect.com/science/article/pii/S0012821X09003847 |journal=Earth and Planetary Science Letters |series=Mars Express after 6 Years in Orbit: Mars Geology from Three-Dimensional Mapping by the High Resolution Stereo Camera (HRSC) Experiment |language=en |volume=294 |issue=3 |pages=185–203 |doi=10.1016/j.epsl.2009.06.042 |issn=0012-821X}}</ref> |
|||
{{Mars timescale}} |
|||
A second time scale based on mineral alteration observed by the OMEGA [[spectrometer]] on-board the [[Mars Express]]. Using this method, three periods were defined, the Phyllocian (~4,500–4,000 Ma), Theiikian (~4,000–3,500 Ma), and Siderikian (~3,500 Ma to present). <ref name="Bibring_2006">{{Cite journal |last=Bibring |first=Jean-Pierre |last2=Langevin |first2=Yves |last3=Mustard |first3=John F. |last4=Poulet |first4=François |last5=Arvidson |first5=Raymond |last6=Gendrin |first6=Aline |last7=Gondet |first7=Brigitte |last8=Mangold |first8=Nicolas |last9=Pinet |first9=P. |last10=Forget |first10=F. |last11=Berthé |first11=Michel |date=2006-04-21 |title=Global Mineralogical and Aqueous Mars History Derived from OMEGA/Mars Express Data |url=https://www.science.org/doi/10.1126/science.1122659 |journal=Science |language=en |volume=312 |issue=5772 |pages=400–404 |doi=10.1126/science.1122659 |issn=0036-8075}}</ref> |
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id:ediacaran value:rgb(0.996,0.85,0.415) |
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id:cryogenian value:rgb(0.996,0.8,0.36) |
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id:tonian value:rgb(0.996,0.75,0.305) |
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id:mesoproterozoic value:rgb(0.996,0.705,0.384) |
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id:rodinian value:rgb(0.996,0.75,0.478) |
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id:paleoproterozoic value:rgb(0.968,0.263,0.44) |
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id:columbian value:rgb(0.968,0.459,0.655) |
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id:eukaryian value:rgb(0.968,0.408,0.596) |
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id:oxygenian value:rgb(0.968,0.357,0.537) |
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id:archean value:rgb(0.996,0.157,0.498) |
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id:neoarchean value:rgb(0.976,0.608,0.757) |
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id:siderian value:rgb(0.976,0.7,0.85) |
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id:methanian value:rgb(0.976,0.65,0.8) |
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id:mesoarchean value:rgb(0.968,0.408,0.662) |
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id:pongolan value:rgb(0.968,0.5,0.75) |
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id:vaalbaran value:rgb(0.968,0.45,0.7) |
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id:paleoarchean value:rgb(0.96,0.266,0.624) |
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id:isuan value:rgb(0.96,0.35,0.65) |
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id:acastan value:rgb(0.96,0.3,0.6) |
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id:hadean value:rgb(0.717,0,0.494) |
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id:zirconian value:rgb(0.902,0.114,0.549) |
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id:chaotian value:rgb(0.8,0.05,0.5) |
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id:black value:black |
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id:white value:white |
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align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5) |
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bar:supereon |
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from: -4567 till: -541 text:[[Precambrian]] color:precambrian |
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from: start till: -4567 color:white |
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bar:eon |
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from: -2420 till: -541 text:[[Proterozoic]] color:proterozoic |
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from: -4030 till: -2420 text:[[Archean]] color:archean |
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from: -4567 till: -4030 text:[[Hadean]] color:hadean |
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from: start till: -4567 color:white |
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bar:era |
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from: -850 till: -541 text:[[Neoproterozoic]] color:neoproterozoic |
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from: -1780 till: -850 text:[[Mesoproterozoic]] color:mesoproterozoic |
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from: -2420 till: -1780 text:[[Paleoproterozoic]] color:paleoproterozoic |
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from: -2780 till: -2420 text:[[Neoarchean]] color:neoarchean |
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from: -3490 till: -2780 text:[[Mesoarchean]] color:mesoarchean |
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from: -4030 till: -3490 text:[[Paleoarchean]] color:paleoarchean |
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from: -4404 till: -4030 text:Zirconian color:zirconian |
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from: -4567 till: -4404 text:[[Chaotian]] color:chaotian |
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from: start till: -4567 color:white |
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bar:period |
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fontsize:6 |
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from: -630 till: -541 text:[[Ediacaran|Ed.]] color:ediacaran |
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from: -850 till: -630 text:[[Cryogenian]] color:cryogenian |
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from: -1780 till: -850 text:[[Rodinian]] color:rodinian |
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from: -2060 till: -1780 text:[[Columbian]] color:columbian |
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from: -2250 till: -2060 text:[[Eukaryian]] color:eukaryian |
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from: -2420 till: -2250 text:[[Oxygenian]] color:oxygenian |
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from: -2630 till: -2420 text:[[Siderian]] color:siderian |
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from: -2780 till: -2630 text:[[Methanian]] color:methanian |
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from: -3020 till: -2780 text:[[Pongolan]] color:pongolan |
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from: -3490 till: -3020 text:[[Vaalbaran]] color:vaalbaran |
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from: -3810 till: -3490 text:[[Isuan]] color:isuan |
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from: -4030 till: -3810 text:[[Acastan]] color:acastan |
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from: start till: -4030 color:white |
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</timeline> |
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Compare with the current official timeline, shown to scale: |
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<timeline> |
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id: |
id:sidericol value:rgb(1,0.4,0.3) |
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id: |
id:theiicol value:rgb(1,0.2,0.5) |
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id: |
id:phyllocol value:rgb(0.7,0.4,1) |
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id:ediacaran value:rgb(0.996,0.85,0.415) |
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id:cryogenian value:rgb(0.996,0.8,0.36) |
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id:tonian value:rgb(0.996,0.75,0.305) |
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id:mesoproterozoic value:rgb(0.996,0.705,0.384) |
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id:stenian value:rgb(0.996,0.85,0.604) |
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id:ectasian value:rgb(0.996,0.8,0.541) |
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id:calymmian value:rgb(0.996,0.75,0.478) |
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id:paleoproterozoic value:rgb(0.968,0.263,0.44) |
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id:statherian value:rgb(0.968,0.459,0.655) |
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id:orosirian value:rgb(0.968,0.408,0.596) |
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id:rhyacian value:rgb(0.968,0.357,0.537) |
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id:siderian value:rgb(0.968,0.306,0.478) |
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id:archean value:rgb(0.996,0.157,0.498) |
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id:neoarchean value:rgb(0.976,0.608,0.757) |
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id:mesoarchean value:rgb(0.968,0.408,0.662) |
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id:paleoarchean value:rgb(0.96,0.266,0.624) |
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id:eoarchean value:rgb(0.902,0.114,0.549) |
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id:hadean value:rgb(0.717,0,0.494) |
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id:black value:black |
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id:white value:white |
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PlotData= |
PlotData= |
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align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5) |
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bar:supereon |
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from: start till: -541 text:[[Precambrian]] color:precambrian |
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bar:eon |
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from: -2500 till: -541 text:[[Proterozoic]] color:proterozoic |
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from: -4000 till: -2500 text:[[Archean]] color:archean |
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from: start till: -4000 text:[[Hadean]] color:hadean |
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bar:era |
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from: -1000 till: -541 text:[[Neoproterozoic]] color:neoproterozoic |
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from: -1600 till: -1000 text:[[Mesoproterozoic]] color:mesoproterozoic |
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from: -2500 till: -1600 text:[[Paleoproterozoic]] color:paleoproterozoic |
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from: -2800 till: -2500 text:[[Neoarchean]] color:neoarchean |
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from: -3200 till: -2800 text:[[Mesoarchean]] color:mesoarchean |
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from: -3600 till: -3200 text:[[Paleoarchean]] color:paleoarchean |
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from: -4000 till: -3600 text:[[Eoarchean]] color:eoarchean |
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from: start till: -4000 color:white |
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bar:period |
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text:Siderikan from:-3500 till:0 color:sidericol |
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fontsize:6 |
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text:Theiikian from:-4000 till:-3500 color:theiicol |
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text:Phyllocian from:start till:-4000 color:phyllocol |
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from: -1000 till: -720 text:[[Tonian]] color:tonian |
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from: -1200 till: -1000 text:[[Stenian]] color:stenian |
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from: -1400 till: -1200 text:[[Ectasian]] color:ectasian |
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from: -1600 till: -1400 text:[[Calymmian]] color:calymmian |
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from: -1800 till: -1600 text:[[Statherian]] color:statherian |
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from: -2050 till: -1800 text:[[Orosirian]] color:orosirian |
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from: -2300 till: -2050 text:[[Rhyacian]] color:rhyacian |
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from: -2500 till: -2300 text:[[Siderian]] color:siderian |
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from: start till: -2500 color:white |
|||
</timeline> |
</timeline> |
||
==See also== |
== See also == |
||
<!-- |
<!--Please keep entries in alphabetical order & add a short description [[WP:SEEALSO]]--> |
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{{div col|colwidth= |
{{div col|colwidth=15em|small=yes}} |
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* [[Age of Earth]] |
* [[Age of the Earth]] |
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* [[ |
* [[Cosmic calendar]] |
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* [[Cosmic Calendar]] |
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* [[Deep time]] |
* [[Deep time]] |
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* [[ |
* [[Evolutionary history of life]] |
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* [[Formation and evolution of the Solar System]] |
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* [[Geological history of Earth]] |
* [[Geological history of Earth]] |
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* [[Geology of Mars]] |
* [[Geology of Mars]] |
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* [[Geon (geology) |
* [[Geon (geology)]] |
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* [[Graphical timeline of the universe]] |
* [[Graphical timeline of the universe]] |
||
* [[History of Earth]] |
* [[History of the Earth]] |
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* [[History of geology]] |
* [[History of geology]] |
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* [[History of paleontology]] |
* [[History of paleontology]] |
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* [[Logarithmic timeline]] |
* [[Logarithmic timeline]] |
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* [[Lunar geologic timescale]] |
* [[Lunar geologic timescale]] |
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* [[ |
* [[Martian geologic timescale]] |
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* [[Natural history]] |
* [[Natural history]] |
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* [[New Zealand geologic time scale]] |
* [[New Zealand geologic time scale]] |
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* [[ |
* [[Prehistoric life]] |
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* [[Timeline of the |
* [[Timeline of the Big Bang]] |
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* [[Timeline of evolution]] |
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* [[Timeline of the geologic history of the United States]] |
* [[Timeline of the geologic history of the United States]] |
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* [[Timeline of human evolution]] |
* [[Timeline of human evolution]] |
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* [[Timeline of paleontology]] |
* [[Timeline of paleontology]] |
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{{div col end}} |
{{div col end}} |
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<!-- please keep entries in alphabetical order - per [[WP:ALSO]] --> |
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== Notes == |
== Notes == |
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{{Notelist}} |
{{Notelist|group=note}} |
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== References == |
== References == |
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Line 1,020: | Line 1,153: | ||
{{Commons category|Geologic time scale}} |
{{Commons category|Geologic time scale}} |
||
{{Wikibooks|Historical Geology|Geological column}} |
{{Wikibooks|Historical Geology|Geological column}} |
||
* The current version of the International Chronostratigraphic Chart can be found at [https://stratigraphy.org/chart stratigraphy.org/chart] |
|||
* [https://stratigraphy.org/timescale/ International Chronostratigraphic Chart (interactive)] |
|||
* Interactive version of the International Chronostratigraphic Chart is found at [https://stratigraphy.org/timescale stratigraphy.org/timescale] |
|||
* [https://stratigraphy.org/icschart/ChronostratChart2020-03.pdf International Chronostratigraphic Chart (v 2020/03)] |
|||
* [https://stratigraphy.org/gssps/ |
* A list of current Global Boundary Stratotype and Section Points is found at [https://stratigraphy.org/gssps/ stratigraphy.org/gssps] |
||
* [https://web.archive.org/web/20050418090602/http://rst.gsfc.nasa.gov/Sect2/Sect2_1b.html NASA: Geologic Time] |
* [https://web.archive.org/web/20050418090602/http://rst.gsfc.nasa.gov/Sect2/Sect2_1b.html NASA: Geologic Time] |
||
* [https://web.archive.org/web/20190120115100/https://www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx GSA: Geologic Time Scale] |
* [https://web.archive.org/web/20190120115100/https://www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx GSA: Geologic Time Scale] |
Revision as of 09:59, 5 June 2022
![Geologic time scale with proportional representation of eons/eonothems and eras/erathems. Cenozoic is abbreviated to Cz. The image also shows some notable events in Earth's history and the general evolution of life.](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f0/GeologicTimeScale-WikiLeadImage.svg/300px-GeologicTimeScale-WikiLeadImage.svg.png)
The geologic time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (scientific branch of geology that aims to determine the age of rocks). It is used by primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardized international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective[1] is to precisely define global chronostratigraphic units of the International Chronostratigraphic Chart (ICC)[2] that are used to define divisions of geologic time. The chronostratigraphic divisions are in turn used to define geochronologic units.[2]
While some regional terms are still in use,[3] the table of geologic time presented on this page conforms to the nomenclature, ages, and colour codes set forth by the ICS as this is the standard, reference global geologic time scale.[1]
Principles
The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years).[4] It chronologically organizes strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or paleontological events. For example, the Cretaceous–Paleogene extinction event, marks the lower boundary of the Paleogene System/Period and thus the boundary between the Cretaceous and Paleogene Systems/Periods. For divisions prior to the Cryogenian, arbitrary numeric boundary definitions (GSSAs) are used to divide geologic time. Proposals have been made to better reconcile these divisions with the rock record.[5][3]
Historically, regional geologic time scales were used[3] due to the litho- and biostratigraphic differences around the world in time equivalent rocks. The ICS has long worked to reconcile conflicting terminology by standardizing globally significant and identifiable stratigraphic horizons that can be used to define the lower boundaries of chronostratigraphic units. Defining chronostratigraphic units in such a manner allows for the use of global, standardised nomenclature. The ICC represents this ongoing effort.
The relative relationships of rocks for determining the chronostratigraphic positions use the overriding principles of:
- Superposition – Newer rock beds will lie on top of older rock beds unless the succession has been overturned.
- Horizontality – All rock layers were originally deposited horizontally.[note 1]
- Lateral continuity – Originally deposited layers of rock extend laterally in all directions until either thinning out or being cut off by a different rock layer.
- Biologic succession (where applicable) – This states that each stratum in a succession contains a distinctive set of fossils. This allows for correlation of stratum even when the horizon between them is not continuous.
- Cross-cutting relationships – A rock feature that cuts across another feature must be younger than the rock it cuts.
- Inclusion – Small fragments of one type of rock but embedded in a second type of rock must have formed first, and were included when the second rock was forming.
- Relationships of unconformities – Geologic features representing periods of erosion or non-deposition, indicating non-continuous sediment deposition.
Terminology
The GTS is divided into chronostratigraphic units and their corresponding geochronologic units. These are represented on the ICC published by the ICS; however, regional terms are still in use in some areas.
Chronostratigraphy is the element of stratigraphy that deals with the relation between rock bodies and the relative measurement of geological time.[6] It is the process where distinct strata between defined stratigraphic horizons are assigned to represent a relative interval of geologic time.
A chronostratigraphic unit is a body of rock, layered or unlayered, that is defined between specified stratigraphic horizons which represent specified intervals of geologic time. They include all rocks representative of a specific interval of geologic time, and only this time span.[6]
A geochronologic unit is a subdivision of geologic time. It is a numeric representation of an intangible property (time).[7] Eon, era, period, epoch, subepoch, age, and subage are the hierarchical geochronologic units.[6] Geochronometry is the field of geochronology that numerically quantifies geologic time.[7]
A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundaries of stages on the geologic time scale.[8] (Recently this has been used to define the base of a system)[9]
A Global Standard Stratigraphic Age (GSSA)[10] is a numeric only, chronologic reference point used to define the base of geochronologic units prior to the Cryogenian. These points are arbitrarily defined.[6] As of April 2022[update] there are three formally defined eons/eonothems: the Archean, Proterozoic, and Phanerozoic.[2] The Hadean is an informal eon/eonothem, but is commonly used.[11]
An era is the second largest geochonologic time unit and is the equivalent of a chronostratigraphic erathem.[6][11] As of April 2022[update] there are currently ten defined eras/erathems.[2]
A period is a major rank below an era and above an epoch. It is the geochronologic equivalent of a chronostratigraphic system.[6][11]As of April 2022[update] there are currently 22 defined periods/systems.[2] As an exception two subperiods/subsystems are used for the Carboniferous Period/System.[6]
An epoch is the second smallest geochronologic unit, between a period and an age. It is the equivalent of a chronostratigraphic series.[6][11] As of April 2022[update] there are currently 37 defined and one informal epochs/series. There are also 11 subepochs/subseries which are all within the Neogene and Quaternary.[2] The use of subseries/subepochs as formal ranks/units in international chronostratigraphy was ratified in 2022.[12]
An age is the smallest hierarchical geochonologic unit and is the equivalent of a chronostratigraphic stage.[6][11] As of April 2022[update] there are currently 96 formal and five informal ages/stages.[2]
A chron is a non-hierarchical formal geochronology unit of unspecified rank and is the equivalent of a chronostratigraphic chronozone.[6] These correlate with magnetostratigraphic, lithostratigraphic, or biostratigraphic units as they are based on previously defined stratigraphic units or geologic features.
The Early and Late subdivisions are used as the geochronologic equivalents of the chronostratigraphic Lower and Upper, e.g., Early Triassic Period (geochronologic unit) is used in place of Lower Triassic Series (chronostratigraphic unit).
In essence, it is true to say that rocks representing a given chronostratigraphic unit are that chronostratigraphic unit, and the time they were laid down in is the geochronologic unit, i.e., the rocks that represent the Silurian Series are the Silurian Series and they were deposited during the Silurian Period.
Chronostratigraphic unit (strata) | Geochronologic unit (time) | Time span[note 2] |
---|---|---|
Eonothem | Eon | Several hundred millions of years |
Erathem | Era | Tens to hundreds of millions of years |
System | Period | Millions of years to tens of millions of years |
Series | Epoch | Hundreds of thousands of years to tens of millions of years |
Subseries | Subepoch | Thousands of years to millions of years |
Stage | Age | Thousands to years to millions of years |
Naming of geologic time
The names of geologic time units are defined for chronostratigraphic units with the corresponding geochronologic unit sharing the same name with a change to the suffix (e.g. Phanerozoic Eonothem becomes the Phanerozoic Eon). Names of erathems in the Phanerozoic were chosen to reflect major changes of the history of life on Earth: Paleozoic (old life), Mesozoic (middle life), and Cenozoic (new life). Names of systems are diverse in origin, with some indicating chronologic position (e.g., Paleogene), while others are named for lithology (e.g., Cretaceous), geography (e.g., Permian), or are tribal (e.g., Ordovician) in origin. Most currently recognised series and subseries are named for their position within a system/series (early/middle/late); however, the ICS advocates for all new series and subseries to be named for a geographic feature in the vicinity of its stratotype or type locality. The name of stages should also be derived from a geographic feature in the locality of its stratotype or type locality.[6]
Informally, the time before the Cambrian is often referred to as the pre-Cambrian or Precambrian (Supereon).[5][note 3]
Name | Time Span | Etymology of name |
---|---|---|
Phanerozoic | 538.8 to 0 million years ago | From the Greek words φανερός (phanerós) meaning 'visible' or 'abundant', and ζωή (zoḯ) meaning 'life'. |
Proterozoic | 2,500 to 538.8 million years ago | From the Greek words πρότερος (próteros) meaning 'former' or 'earlier', and ζωή (zoḯ) meaning 'life'. |
Archean | 4,031 to 2,500 million years ago | From the Greek word αρχή (arche), meaning 'beginning, origin'. |
Hadean | ~4,567.3 to 4,031 million years ago | From Hades, the Greek god. |
Name | Time Span | Etymology of name |
---|---|---|
Cenozoic | 66 to 0 million years ago | From the Greek words καινός (kainós) meaning 'new', and ζωή (zoḯ) meaning 'life'. |
Mesozoic | 251.9 to 66 million years ago | From the Greek words μέσο (méso) meaning 'middle', and ζωή (zoḯ) meaning 'life'. |
Paleozoic | 538.8 to 251.9 million years ago | From the Greek words παλιός (palaiós) meaning 'old', and ζωή (zoḯ) meaning 'life'. |
Neoproterozoic | 1,000 to 538.8 million years ago | From the Greek words νέος (néos) meaning 'new' or 'young', πρότερος (próteros) meaning 'former' or 'earlier', and ζωή (zoḯ) meaning 'life'. |
Mesoproterozoic | 1,600 to 1,000 million years ago | From the Greek words μέσο (méso) meaning 'middle', πρότερος (próteros) meaning 'former' or 'earlier', and ζωή (zoḯ) meaning 'life'. |
Paleoproterozoic | 2,500 to 1,600 million years ago | From the Greek words παλιός (palaiós) meaning 'old', πρότερος (próteros) meaning 'former' or 'earlier', and ζωή (zoḯ) meaning 'life'. |
Neoarchean | 2,800 to 2,500 million years ago | From the Greek words νέος (néos) meaning 'new' or 'young', and ἀρχαῖος (arkhaîos) meaning 'ancient'. |
Mesoarchean | 3,200 to 2,800 million years ago | From the Greek words μέσο (méso) meaning 'middle', and ἀρχαῖος (arkhaîos) meaning 'ancient'. |
Paleoarchean | 3,600 to 3,200 million years ago | From the Greek words παλιός (palaiós) meaning 'old', and ἀρχαῖος (arkhaîos) meaning 'ancient'. |
Eoarchean | 4,031 to 3,600 million years ago | From the Greek words Ηώς (Iós) meaning 'dawn', and ἀρχαῖος (arkhaîos) meaning 'ancient'. |
Name | Time Span | Etymology of name |
---|---|---|
Quaternary | 2.6 to 0 million years ago | First introduced by Jules Desnoyers in 1829 for sediments in France's Seine Basin that appeared to be younger than Tertiary[note 4] rocks.[13] |
Neogene | 23 to 2.6 million years ago | Derived from the Greek words νέος (néos) meaning 'new', and γενεά (geneá) meaining 'genesis' or 'birth'. |
Paleogene | 66 to 23 million years ago | Derived from the Greek words παλιός (palaiós) meaning 'old', and γενεά (geneá) meaining 'genesis' or 'birth'. |
Cretaceous | 145 to 66 million years ago | Derived from Terrain Crétacé used in 1822 by Jean d'Omalius d'Halloy in reference to extensive beds of chalk within the Paris Basin.[14] Ultimately derived from the Latin crēta meaning (chalk). |
Jurassic | 201.4 to 145 million years ago | Named after the Jura Mountains. Originally used by Alexander von Humboldt as 'Jura Kalkstein' (Jura limestone) in 1799.[15] Alexandre Brongniart was the first to publish the term Jurassic in 1829.[16][17] |
Triassic | 251.9 to 201.4 million years ago | From the Trias of Friedrich August von Alberti in reference to a trio of formations widespread in southern Germany. |
Permian | 298.9 to 251.9 million years ago | Named after the historical region of Perm, Russian Empire.[18] |
Carboniferous | 358.9 to 298.9 million years ago | Means 'coal-bearing', from the Latin carbō (coal) and ferō (to bear, carry).[19] |
Devonian | 419.2 to 358.9 million years ago | Named after Devon, England.[20] |
Silurian | 443.8 to 419.2 million years ago | Named after the Celtic tribe, the Silures.[21] |
Ordovician | 485.4 to 443.8 million years ago | Named after the Celtic tribe, Ordovices.[22][23] |
Cambrian | 538.8 to 485.4 million years ago | Named for Cambria, a latinised form of the Welsh name for Wales, Crymu.[24] |
Ediacaran | 720 to 635 million years ago | Named for the Ediacara Hills. Ediacara is possibly a corruption of the Kuyani words 'Yata Takarra' meaning hard or stony ground.[25][26] |
Cryogenian | 720 to 635 million years ago | From the Greek words κρύος (krýos) meaning 'cold', and, γένεσις (génesis) meaning 'birth'.[3] |
Tonian | 1,000 to 720 million years ago | From the Greek word τόνος (tónos) meaning 'stretch'.[3] |
Stenian | 1,200 to 1,000 million years ago | From the Greek word στενός (stenós) meaning 'narrow'.[3] |
Ectasian | 1,400 to 1,200 million years ago | From the Greek word ἔκτᾰσῐς (éktasis) meaning 'extension'.[3] |
Calymmian | 1,600 to 1,400 million years ago | From the Greek word κάλυμμᾰ (kálumma) meaning 'cover'.[3] |
Statherian | 1,800 to 1,600 million years ago | From the Greek word σταθερός (statherós) meaning 'stable'.[3] |
Orosirian | 2,050 to 1,800 million years ago | From the Greek word ὀροσειρά (oroseirá) meaning 'mountain range'.[3] |
Rhyacian | 2,300 to 2,050 million years ago | From the Greek word ῥύαξ (rhýax) meaning 'stream of lava'.[3] |
Siderian | 2,500 to 2,300 million years ago | From the Greek word σίδηρος (sídiros) meaning 'iron'.[3] |
History of the geologic time scale
Early history
While a modern geological time scale was not formulated until 1911[27] by Arthur Holmes, the broader concept that rocks and time are related can be traced back to (at least) the philosophers of Ancient Greece. Xenophanes of Colophon (c. 570–487 BCE) observed rock beds with fossils of shells located above the sea-level, viewed them as once living organisms, and used this to imply an unstable relationship in which the sea had at times transgressed over the land and at other times had regressed.[28] This view was shared by a few of Xenophanes' contemporaries and those that followed, including Aristotle (384–322 BCE) who (with additional observations) reasoned that the positions of land and sea had changed over long periods of time. The concept of deep time was also recognised by Chinese naturalist Shen Kuo[29] (1031–1095) and Islamic scientist-philosophers, notably the Brothers of Purity, who wrote on the processes of stratification over the passage of time in their treatises.[28] Their work likely inspired that of the 11th-century Persian polymath Avicenna (Ibn Sînâ, 980–1037) who wrote in The Book of Healing (1027) on the concept of stratification and superposition, pre-dating Nicolas Steno by more than six centuries.[28] Avicenna also recognised fossils as "petrifications of the bodes of plants and animals",[30] with the 13th-century Dominican bishop Albertus Magnus (c. 1200–1280) extending this into a theory of a petrifying fluid.[31][verification needed] These works appeared to have little influence on scholars in Medieval Europe who looked to the Bible to explain the origins of fossils and sea-level changes, often attributing these to the 'Deluge', including Ristoro d'Arezzo in 1282.[28] It was not until the Italian Renaissance when Leonardo da Vinci (1452–1519) would reinvigorate the relationships between stratification, relative sea-level change, and time, denouncing attribution of fossils to the 'Deluge':[32][28]
Of the stupidity and ignorance of those who imagine that these creatures were carried to such places distant from the sea by the Deluge...Why do we find so many fragments and whole shells between the different layers of stone unless they had been upon the shore and had been covered over by earth newly thrown up by the sea which then became petrified? And if the above-mentioned Deluge had carried them to these places from the sea, you would find the shells at the edge of one layer of rock only, not at the edge of many where may be counted the winters of the years during which the sea multiplied the layers of sand and mud brought down by the neighboring rivers and spread them over its shores. And if you wish to say that there must have been many deluges in order to produce these layers and the shells among them it would then become necessary for you to affirm that such a deluge took place every year.
These views of da Vinci remained unpublished, and thus lacked influence at the time; however, questions of fossils and their significance were pursued and, while views against Genesis were not readily accepted and dissent from religious doctrine was in some places unwise, scholars such as Girolamo Fracastoro shared da Vinci's views, and found the attribution of fossils to the 'Deluge' absurd.[28]
Establishment of primary principles
Niels Stensen, more commonly known as Nicolas Steno (1638–1686), is credited with establishing four of the guiding principles of stratigraphy.[28] In De solido intra solidum naturaliter contento dissertationis prodromus Steno states:[33][34]
- When any given stratum was being formed, all the matter resting on it was fluid and, therefore, when the lowest stratum was being formed, none of the upper strata existed.
- ...strata which are either perpendicular to the horizon or inclined to it were at one time parallel to the horizon.
- When any given stratum was being formed, it was either encompassed at its edges by another solid substance or it covered the whole globe of the earth. Hence, it follows that wherever bared edges of strata are seen, either a continuation of the same strata must be looked for or another solid substance must be found that kept the material of the strata from being dispersed.
- If a body or discontinuity cuts across a stratum, it must have formed after that stratum.
Respectively, these are the principles of superposition, original horizontality, lateral continuity, and cross-cutting relationships. From this Steno reasoned that strata were laid down in succession and inferred relative time (in Steno's belief, time from Creation). While Steno's principles were simple and attracted much attention, applying them proved challenging.[28] These basic principles, albeit with improved and more nuanced interpretations, still form the foundational principles of determining correlation of strata relative geologic time.
Over the course of the 18th-century geologists realised that:
- Sequences of strata often become eroded, distorted, tilted, or even inverted after deposition
- Strata laid down at the same time in different areas could have entirely different appearances
- The strata of any given area represented only part of Earth's long history
Formulation of a modern geologic time scale
The apparent, earliest formal division of the geologic record with respect to time was introduced by Thomas Burnet who applied a two-fold terminology to mountains by identifying "montes primarii" for rock formed at the time of the 'Deluge', and younger "monticulos secundarios" formed later from the debris of the "primarii".[35][28] This attribution to the 'Deluge', while questioned earlier by the likes of da Vinci, was the foundation of Abraham Gottlob Werner's (1749–1817) Neptunism theory in which all rocks precipitated out of a single flood.[36] A competing theory, Plutonism, was developed by Anton Moro (1687–1784) and also used primary and secondary divisions for rock units.[37][28] In this early version of the Plutonism theory, the interior of Earth was seen as hot, and this drove the creation of primary igneous and metamorphic rocks and secondary rocks formed contorted and fossiliferous sediments. These primary and secondary divisions were expanded on by Giovanni Targioni Tozzetti (1712–1783) and Giovanni Arduino (1713–1795) to include tertiary and quaternary divisions.[28] These divisions were used to describe both the time during which the rocks were laid down, and the collection of rocks themselves (i.e., it was correct to say Tertiary rocks, and Tertiary Period). Only the Quaternary division is retained in the modern geologic time scale, while the Tertiary division was in use until the early 21st century. The Neputism and Plutonism theories would compete into the early 19th century with a key driver for resolution of this debate being the work of James Hutton (1726–1797), in particular his Theory of the Earth, first presented before the Royal Society of Edinburgh in 1785.[38][39][40] Hutton's theory would later become known as uniformitarianism, popularised by John Playfair[41] (1748–1819) and later Charles Lyell (1797–1875) in his Principles of Geology.[42][43][44] Their theories strongly contested the 6,000 year age of the Earth as suggested determined by James Ussher via Biblical chronology that was accepted at the time by western religion. Instead, using geological evidence, they contested Earth to be much older, cementing the concept of deep time.
During the early 19th century William Smith, Georges Cuvier, Jean d'Omalius d'Halloy, and Alexandre Brongniart pioneered the systematic division of rocks by stratigraphy and fossil assemblages. These geologists began to use the local names given to rock units in a wider sense, correlating strata across national and continental boundaries based on their similarity to each other. Many of the names below erathem/era rank in use on the modern ICC/GTS were determined during the early to mid-19th century.
The advent of geochronometry
During the 19th century, the debate regarding Earth's age was renewed, with geologists estimating ages based on denudation rates and sedimentary thicknesses or ocean chemistry, and physicists determining ages for the cooling of the Earth or the Sun using basic thermodynamics or orbital physics.[4] These estimations varied from 15,000 million years to 0.075 million years depending on method and author, but the estimations of Lord Kelvin and Clarence King were held in high regard at the time due to their pre-eminence in physics and geology. All of these early geochronometric determinations would later prove to be incorrect.
The discovery of radioactive decay by Henri Becquerel, Marie Curie, and Pierre Curie laid the ground work for radiometric dating, but the knowledge and tools required for accurate determination of radiometric ages would not be in place until the mid-1950s.[4] Early attempts at determining ages of uranium minerals and rocks by Ernest Rutherford, Bertram Boltwood, Robert Strutt, and Arthur Holmes, would culminate in what is considered the first international geological time scales by Holmes in 1911 and 1913.[27][45][46] The discovery of isotopes in 1913[47] by Frederick Soddy, and the developments in mass spectrometry pioneered by Francis William Aston, Arthur Jeffrey Dempster, and Alfred O. C. Nier during the early to mid-20th century would finally allow for the accurate determination of radiometric ages, with Holmes publishing several revisions to his geological time-scale with his final version in 1960.[4][46][48][49]
Modern international geologic time scale
The establishment of the IUGS in 1961[50] and acceptance of the Commission on Stratigraphy (applied in 1965)[51] to become a member commission of IUGS led to the founding of the ICS. One of the primary objectives of the ICS is "the establishment, publication and revision of the ICS International Chronostratigraphic Chart which is the standard, reference global Geological Time Scale to include the ratified Commission decisions".[1]
Following on from Holmes, several A Geological Time Scale books were published in 1982,[52] 1989,[53] 2004,[54] 2008,[55] 2012,[56] 2016,[57] and 2020.[58] However, since 2013, the ICS has taken responsibility for producing and distributing the ICC citing the commercial nature, independent creation, and lack oversight of the by ICS on the prior published GTS versions (GTS books prior to 2013) although these versions were published in close association with the ICS.[2] Subsequent Geologic Time Scale books (2016[57] and 2020[58]) are commercial publications with no oversight from the ICS, and do not entirely conform to the chart produced by the ICS. The ICS produced GTS charts are versioned (year/month) beginning at v2013/01. At least one new version is published each year incorporating any changes ratified by the ICS since the prior version.
The following five timelines show the geologic time scale to scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. The second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in the third timeline, the most recent period is expanded in the fourth timeline, and the most recent epoch is expanded in the fifth timeline.
![](http://upload.wikimedia.org/wikipedia/en/timeline/p148jgs61kf4hw62fzi0jv6ku24oq0u.png)
![](http://upload.wikimedia.org/wikipedia/en/timeline/1p7ranz6q1y5dxkzdb8huwzb327mxrf.png)
![](http://upload.wikimedia.org/wikipedia/en/timeline/gulzqjw1x4uvqz9lenmf2nuz0ptfg82.png)
![](http://upload.wikimedia.org/wikipedia/en/timeline/o148ko038imue7clp0z9q0kiq4p4xca.png)
Horizontal scale is Millions of years (above timelines) / Thousands of years (below timeline)
![](http://upload.wikimedia.org/wikipedia/en/timeline/1z5nfnmb6fll33dfhma8c94aq05ywqf.png)
Major proposed revisions to the ICC
Proposed Anthropocene Series/Epoch
First suggested in 2000,[59] the Anthropocene is a proposed epoch/series for the most recent time in Earth's history. While still informal, it is a widely used term to denote the present geologic time interval, in which many conditions and processes on Earth are profoundly altered by human impact.[60] As of April 2022[update] the Anthropocene has not been ratified by the ICS; however, in May 2019 the Anthropocene Working Group voted in favour of submitting a formal proposal to the ICS for the establishment of the Anthropocene Series/Epoch.[61] However, the definition of the Anthropocene as a geologic time period rather than a geologic event remains controversial and difficult.[62][63][64][65]
Proposals for revisions to pre-Cryogenian timeline
Shields et al. 2021
An international working group of the ICS on pre-Cryogenian chronostratigraphic subdivision have outlined a template to improve the pre-Cyrogenian geologic time scale based on the rock record to bring it in line with the post-Tonian geologic time scale.[5] This work assessed the geologic history of the currently defined eons and eras of the pre-Cambrian,[note 3] and the proposals in the "Geological Time Scale" books 2004,[66] 2012,[3] and 2020.[67] Their recommend revisions[5] of the pre-Cryogenian geologic time scale were (changes from the current scale [v2022/02] are italicised):
- Three divisions of the Archean instead of four by dropping Eoarchean, and revisions to their geochronometric definition, along with the repositioning of the Siderian into the latest Neoarchean, and a potential Kratian division in the Neoarchean.
- Archean (4000–2450 Ma)
- Paleoarchean (4000–3500 Ma)
- Mesoarchean (3500–3000 Ma)
- Neoarchean (3500–2450 Ma)
- Kratian (no fixed time given, prior to the Siderian) – from Greek word κράτος (krátos), meaning strength.
- Siderian (?–2450 Ma) – moved from Proterozoic to end of Archean, no start time given, base of Paleoproterozoic defines the end of the Siderian
- Archean (4000–2450 Ma)
- Refinement of geochronometric divisions of the Proterozoic, Paleoproterozoic, repositioning of the Statherian into the Mesoproterozoic, new Skourian period/system in the Paleoproterozoic, new Kleisian or Syndian period/system in the Neoproterozoic.
- Paleoproterozoic (2450–1800 Ma)
- Skourian (2450–2300 Ma) – from the Greek word σκουριά (skouriá), meaning 'rust'.
- Rhyacian (2300–2050 Ma)
- Orosirian (2050–1800 Ma)
- Mesoproterozoic (1800–1000 Ma)
- Statherian (1800–1600 Ma)
- Calymmian (1600–1400 Ma)
- Ectasian (1400-1200 Ma)
- Stenian (1200–1000 Ma)
- Neoproterozoic (1000–538.8 Ma)[note 5]
- Kleisian or Syndian (1000–800 Ma) – respectively from the Greek words κλείσιμο (kleísimo) meaning 'closure', and σύνδεση (sýndesi) meaning 'connection'.
- Tonian (800–720 Ma)
- Cryogenian (720–635 Ma)
- Ediacaran (635–538.8 Ma)
- Paleoproterozoic (2450–1800 Ma)
Proposed pre-Cambrian timeline (Shield et al. 2021, ICS working group on pre-Cryogenian chronostratigraphy), shown to scale:[note 6]
![](http://upload.wikimedia.org/wikipedia/en/timeline/l5zd2j9hyfau3v6kr4b0e4yc6n0opnw.png)
Current ICC pre-Cambrian timeline (v2022/02), shown to scale:
![](http://upload.wikimedia.org/wikipedia/en/timeline/ejwegsh9yceu43auapxn5b3q9ztlf1s.png)
Van Kranendonk et al. 2012 (GTS2012)
The book, Geologic Time Scale 2012, was the last commercial publication of an international chronostratigraphic chart that was closely associated with the ICS.[2] It included a proposal to substantially revise the pre-Cryogenian time scale to reflect important events such as the formation of the solar system and the Great Oxidation Event, among others, while at the same time maintaining most of the previous chronostratigraphic nomenclature for the pertinent time span.[56] As of April 2022[update] these proposed changes have not been accepted by the ICS. The proposed changes were (changes from the current scale [v2022/02] are italicised):
- Hadean Eon (4567–4030 Ma)
- Chaotian Era/Erathem (4567–4404 Ma) – the name alluding both to the mythological Chaos and the chaotic phase of planet formation.[56][68][69]
- Jack Hillsian or Zirconian Era/Erathem (4404–4030 Ma) – both names allude to the Jack Hills Greenstone Belt which provided the oldest mineral grains on Earth, zircons.[56][68]
- Archean Eon/Eonothem (4030–2420 Ma)
- Paleoarchean Era/Erathem (4030–3490 Ma)
- Acastan Period/System (4030–3810 Ma) – named after the Acasta Gneiss, one of the oldest preserved pieces of continental crust.[56][68]
- Isuan Period (3810–3490 Ma) – named after the Isua Greenstone Belt.[56]
- Mesoarchean Era/Erathem (3490–2780 Ma)
- Vaalbaran Period/System (3490–3020 Ma) – based on the names of the Kapvaal (Southern Africa) and Pilbara (Western Australia) cratons, to reflect the growth of stable continental nuclei or proto-cratonic kernels.[56]
- Pongolan Period/System (3020–2780 Ma) – named after the Pongola Supergroup, in reference to the well preserved evidence of terrestrial microbial communities in those rocks.[56]
- Neoarchean Era/Erathem (2780–2420 Ma)
- Methanian Period/System (2780–2630 Ma) – named for the inferred predominance of methanotrophic prokaryotes[56]
- Siderian Period/System (2630–2420 Ma) – named for the voluminous banded iron formations formed within its duration.[56]
- Paleoarchean Era/Erathem (4030–3490 Ma)
- Proterozoic Eon/Eonothem (2420–538.8 Ma)[note 5]
- Paleoproterozoic Era/Erathem (2420–1780 Ma)
- Oxygenian Period/System (2420–2250 Ma) – named for displaying the first evidence for a global oxidizing atmosphere.[56]
- Jatulian or Eukaryian Period/System (2250–2060 Ma) – names are respectively for the Lomagundi–Jatuli δ13C isotopic excursion event spanning its duration, and for the (proposed)[70][71] first fossil appearance of eukaryotes.[56]
- Columbian Period/System (2060–1780 Ma) – named after the supercontinent Columbia.[56]
- Mesoproterozoic Era/Erathem (1780–850 Ma)
- Paleoproterozoic Era/Erathem (2420–1780 Ma)
Proposed pre-Cambrian timeline (GTS2012), shown to scale:
![](http://upload.wikimedia.org/wikipedia/en/timeline/q8pa43zs9yaj469ym533h04578dxh4r.png)
Current ICC pre-Cambrian timeline (v2022/02), shown to scale:
![](http://upload.wikimedia.org/wikipedia/en/timeline/c4t196u3qoj0ddlvhnwvc4mqqglad22.png)
Table of geologic time
The following table summarises the major events and characteristics of the divisions making up the geologic time scale of Earth. This table is arranged with the most recent geologic periods at the top, and the oldest at the bottom. The height of each table entry does not correspond to the duration of each subdivision of time. As such, this table is not to scale and does not accurately represent the relative time-spans of each geochronologic unit. While the Phanerozoic Eon looks longer than the rest, it merely spans ~539 million years (~12% of Earth's history), whilst the previous three eons[note 3] collectively span ~3,461 million years (~76% of Earth's history). This bias toward the most recent eon is in part due to the relative lack of information about events that occurred during the first three eons compared to the current eon (the Phanerozoic).[5][72] The use of subseries/subepochs has been ratified by the ICS.[12]
The content of the table is based on the official ICC produced and maintained by the ICS who also provide an online interactive version of this chart. The interactive version is based on a service delivering a machine-readable Resource Description Framework/Web Ontology Language representation of the time scale, which is available through the Commission for the Management and Application of Geoscience Information GeoSciML project as a service[73] and at a SPARQL end-point.[74][75]
Eonothem/ Eon |
Erathem/ Era |
System/ Period |
Series/ Epoch |
Stage/ Age |
Major events | Start, million years ago [note 7] |
---|---|---|---|---|---|---|
Phanerozoic | Cenozoic [note 4] |
Quaternary | Holocene | Meghalayan | 4.2-kiloyear event, Austronesian expansion, increasing industrial CO2. | 0.0042 * |
Northgrippian | 8.2-kiloyear event, Holocene climatic optimum. Sea level flooding of Doggerland and Sundaland. Sahara becomes a desert. End of Stone Age and start of recorded history. Humans finally expand into the Arctic Archipelago and Greenland. | 0.0082 * | ||||
Greenlandian | Climate stabilizes. Current interglacial and Holocene extinction begins. Agriculture begins. Humans spread across the wet Sahara and Arabia, the Extreme North, and the Americas (mainland and the Caribbean). | 0.0117 ± 0.000099 * | ||||
Pleistocene | Upper/Late ('Tarantian') | Eemian interglacial, last glacial period, ending with Younger Dryas. Toba eruption. Pleistocene megafauna (including the last terror birds) extinction. Humans expand into Near Oceania and the Americas. | 0.129 | |||
Chibanian | Mid-Pleistocene Transition occurs, high amplitude 100 ka glacial cycles. Rise of Homo sapiens. | 0.774 * | ||||
Calabrian | Further cooling of the climate. Giant terror birds go extinct. Spread of Homo erectus across Afro-Eurasia. | 1.8 * | ||||
Gelasian | Start of Quaternary glaciations and unstable climate.[76] Rise of the Pleistocene megafauna and Homo habilis. | 2.58 * | ||||
Neogene | Pliocene | Piacenzian | Greenland ice sheet develops[77] as the cold slowly intensifies towards the Pleistocene. Atmospheric O2 and CO2 content reaches present day levels while landmasses also reach their current locations (e.g. the Isthmus of Panama joins the North and South Americas, while allowing a faunal interchange). The last non-marsupial metatherians go extinct. Australopithecus common in East Africa; Stone Age begins.[78] | 3.6 * | ||
Zanclean | Zanclean flooding of the Mediterranean Basin. Cooling climate continues from the Miocene. First equines and elephantines. Ardipithecus in Africa.[78] | 5.333 * | ||||
Miocene | Messinian | Messinian Event with hypersaline lakes in empty Mediterranean Basin. Moderate icehouse climate, punctuated by ice ages and re-establishment of East Antarctic Ice Sheet. Choristoderes, the last non-crocodilian crocodylomorphs and creodonts go extinct. After separating from gorilla ancestors, chimpanzee and human ancestors gradually separate; Sahelanthropus and Orrorin in Africa. | 7.246 * | |||
Tortonian | 11.63 * | |||||
Serravallian | Middle Miocene climate optimum temporarily provides a warm climate. [79] Extinctions in middle Miocene disruption, decreasing shark diversity. First hippos. Ancestor of great apes. | 13.82 * | ||||
Langhian | 15.98 | |||||
Burdigalian | Orogeny in Northern Hemisphere. Start of Kaikoura Orogeny forming Southern Alps in New Zealand. Widespread forests slowly draw in massive amounts of CO2, gradually lowering the level of atmospheric CO2 from 650 ppmv down to around 100 ppmv during the Miocene.[80][note 8] Modern bird and mammal families become recognizable. The last of the primitive whales go extinct. Grasses become ubiquitous. Ancestor of apes, including humans.[81][82] Afro-Arabia collides with Eurasia, fully forming the Alpide Belt and closing the Tethys Ocean, while allowing a faunal interchange. At the same time, Afro-Arabia splits into Africa and West Asia. | 20.44 | ||||
Aquitanian | 23.03 * | |||||
Paleogene | Oligocene | Chattian | Grande Coupure extinction. Start of widespread Antarctic glaciation.[83] Rapid evolution and diversification of fauna, especially mammals (e.g. first macropods and seals). Major evolution and dispersal of modern types of flowering plants. Cimolestans, miacoids and condylarths go extinct. First neocetes (modern, fully aquatic whales) appear. | 27.82 | ||
Rupelian | 33.9 * | |||||
Eocene | Priabonian | Moderate, cooling climate. Archaic mammals (e.g. creodonts, miacoids, "condylarths" etc.) flourish and continue to develop during the epoch. Appearance of several "modern" mammal families. Primitive whales and sea cows diversify after returning to water. Birds continue to diversify. First kelp, diprotodonts, bears and simians. The multituberculates and leptictidans go extinct by the end of the epoch. Reglaciation of Antarctica and formation of its ice cap; End of Laramide and Sevier Orogenies of the Rocky Mountains in North America. Hellenic Orogeny begins in Greece and Aegean Sea. | 37.71 * | |||
Bartonian | 41.2 | |||||
Lutetian | 47.8 * | |||||
Ypresian | Two transient events of global warming (PETM and ETM-2) and warming climate until the Eocene Climatic Optimum. The Azolla event decreased CO2 levels from 3500 ppm to 650 ppm, setting the stage for a long period of cooling.[80][note 8] Greater India collides with Eurasia and starts Himalayan Orogeny (allowing a biotic interchange) while Eurasia completely separates from North America, creating the North Atlantic Ocean. Maritime Southeast Asia diverges from the rest of Eurasia. First passerines, ruminants, pangolins, bats and true primates. | 56 * | ||||
Paleocene | Thanetian | Starts with Chicxulub impact and the K-Pg extinction event, wiping out all non-avian dinosaurs and pterosaurs, most marine reptiles, many other vertebrates (e.g. many Laurasian metatherians), most cephalopods (only Nautilidae and Coleoidea survived) and many other invertebrates. Climate tropical. Mammals and birds (avians) diversify rapidly into a number of lineages following the extinction event (while the marine revolution stops). Multituberculates and the first rodents widespread. First large birds (e.g. ratites and terror birds) and mammals (up to bear or small hippo size). Alpine orogeny in Europe and Asia begins. First proboscideans and plesiadapiformes (stem primates) appear. Some marsupials migrate to Australia. | 59.2 * | |||
Selandian | 61.6 * | |||||
Danian | 66 * | |||||
Mesozoic | Cretaceous | Upper/Late | Maastrichtian | Flowering plants proliferate (after developing many features since the Carboniferous), along with new types of insects, while other seed plants (gymnosperms and seed ferns) decline. More modern teleost fish begin to appear. Ammonoids, belemnites, rudist bivalves, sea urchins and sponges all common. Many new types of dinosaurs (e.g. tyrannosaurs, titanosaurs, hadrosaurs, and ceratopsids) evolve on land, while crocodilians appear in water and probably cause the last temnospondyls to die out; and mosasaurs and modern types of sharks appear in the sea. The revolution started by marine reptiles and sharks reaches its peak, though ichthyosaurs vanish few million years after being heavily reduced at the Bonarelli Event. Toothed and toothless avian birds coexist with pterosaurs. Modern monotremes, metatherian (including marsupials, who migrate to South America) and eutherian (including placentals, leptictidans and cimolestans) mammals appear while the last non-mammalian cynodonts die out. First terrestrial crabs. Many snails become terrestrial. Further breakup of Gondwana creates South America, Afro-Arabia, Antarctica, Oceania, Madagascar, Greater India, and the South Atlantic, Indian and Antarctic Oceans and the islands of the Indian (and some of the Atlantic) Ocean. Beginning of Laramide and Sevier Orogenies of the Rocky Mountains. Atmospheric oxygen and carbon dioxide levels similar to present day. Acritarchs disappear. Climate initially warm, but later it cools. | 72.1 ± 0.2 * | |
Campanian | 83.6 ± 0.2 | |||||
Santonian | 86.3 ± 0.5 * | |||||
Coniacian | 89.8 ± 0.3 | |||||
Turonian | 93.9 * | |||||
Cenomanian | 100.5 * | |||||
Lower/Early | Albian | ~113 * | ||||
Aptian | ~121.4 | |||||
Barremian | ~125.77 | |||||
Hauterivian | ~132.6 * | |||||
Valanginian | ~139.8 | |||||
Berriasian | ~145 | |||||
Jurassic | Upper/Late | Tithonian | Climate becomes humid again. Gymnosperms (especially conifers, cycads and cycadeoids) and ferns common. Dinosaurs, including sauropods, carnosaurs, stegosaurs and coelurosaurs, become the dominant land vertebrates. Mammals diversify into shuotheriids, australosphenidans, eutriconodonts, multituberculates, symmetrodonts, dryolestids and boreosphenidans but mostly remain small. First birds, lizards, snakes and turtles. First brown algae, rays, shrimps, crabs and lobsters. Parvipelvian ichthyosaurs and plesiosaurs diverse. Rhynchocephalians throughout the world. Bivalves, ammonoids and belemnites abundant. Sea urchins very common, along with crinoids, starfish, sponges, and terebratulid and rhynchonellid brachiopods. Breakup of Pangaea into Laurasia and Gondwana, with the latter also breaking into two main parts; the Pacific and Arctic Oceans form. Tethys Ocean forms. Nevadan orogeny in North America. Rangitata and Cimmerian orogenies taper off. Atmospheric CO2 levels 3–4 times the present day levels (1200–1500 ppmv, compared to today's 400 ppmv[80][note 8]). Crocodylomorphs (last pseudosuchians) seek out an aquatic lifestyle. Mesozoic marine revolution continues from late Triassic. Tentaculitans disappear. | 149.2 ± 0.9 | ||
Kimmeridgian | 154.8 ± 1.0 | |||||
Oxfordian | 161.5 ± 1.0 | |||||
Middle | Callovian | 165.3 ± 1.2 | ||||
Bathonian | 168.2 ± 1.3 * | |||||
Bajocian | 170.9 ± 1.4 * | |||||
Aalenian | 174.7 ± 1.0 * | |||||
Lower/Early | Toarcian | 184.2 ± 0.7 * | ||||
Pliensbachian | 192.9 * | |||||
Sinemurian | 199.5 ± 0.3 * | |||||
Hettangian | 201.4 ± 0.2 * | |||||
Triassic | Upper/Late | Rhaetian | Archosaurs dominant on land as pseudosuchians and in the air as pterosaurs. Dinosaurs also arise from bipedal archosaurs. Ichthyosaurs and nothosaurs (a group of sauropterygians) dominate large marine fauna. Cynodonts become smaller and nocturnal, eventually becoming the first true mammals, while other remaining synapsids die out. Rhynchosaurs (archosaur relatives) also common. Seed ferns called Dicroidium remained common in Gondwana, before being replaced by advanced gymnosperms. Many large aquatic temnospondyl amphibians. Ceratitidan ammonoids extremely common. Modern corals and teleost fish appear, as do many modern insect orders and suborders. First starfish. Andean Orogeny in South America. Cimmerian Orogeny in Asia. Rangitata Orogeny begins in New Zealand. Hunter-Bowen Orogeny in Northern Australia, Queensland and New South Wales ends, (c. 260–225 Ma). Carnian pluvial event occurs around 234-232 Ma, allowing the first dinosaurs and lepidosaurs (including rhynchocephalians) to radiate. Triassic-Jurassic extinction event occurs 201 Ma, wiping out all conodonts and the last parareptiles, many marine reptiles (e.g. all sauropterygians except plesiosaurs and all ichthyosaurs except parvipelvians), all crocopodans except crocodylomorphs, pterosaurs, and dinosaurs, and many ammonoids (including the whole Ceratitida), bivalves, brachiopods, corals and sponges. First diatoms.[84] | ~208.5 | ||
Norian | ~227 | |||||
Carnian | ~237 * | |||||
Middle | Ladinian | ~242 * | ||||
Anisian | 247.2 | |||||
Lower/Early | Olenekian | 251.2 | ||||
Induan | 251.902 ± 0.024 * | |||||
Paleozoic | Permian | Lopingian | Changhsingian | Landmasses unite into supercontinent Pangaea, creating the Urals, Ouachitas and Appalachians, among other mountain ranges (the superocean Panthalassa or Proto-Pacific also forms). End of Permo-Carboniferous glaciation. Hot and dry climate. A possible drop in oxygen levels. Synapsids (pelycosaurs and therapsids) become widespread and dominant, while parareptiles and temnospondyl amphibians remain common, with the latter probably giving rise to modern amphibians in this period. In the mid-Permian, lycophytes are heavily replaced by ferns and seed plants. Beetles and flies evolve. The very large arthropods and non-tetrapod tetrapodomorphs go extinct. Marine life flourishes in warm shallow reefs; productid and spiriferid brachiopods, bivalves, forams, ammonoids (including goniatites), and orthoceridans all abundant. Crown reptiles arise from earlier diapsids, and split into the ancestors of lepidosaurs, kuehneosaurids, choristoderes, archosaurs, testudinatans, ichthyosaurs, thalattosaurs, and sauropterygians. Cynodonts evolve from larger therapsids. Olson's Extinction (273 Ma), End-Capitanian extinction (260 Ma), and Permian-Triassic extinction event (252 Ma) occur one after another: more than 80% of life on Earth becomes extinct in the lattermost, including most retarian plankton, corals (Tabulata and Rugosa die out fully), brachiopods, bryozoans, gastropods, ammonoids (the goniatites die off fully), insects, parareptiles, synapsids, amphibians, and crinoids (only articulates survived), and all eurypterids, trilobites, graptolites, hyoliths, edrioasteroid crinozoans, blastoids and acanthodians. Ouachita and Innuitian orogenies in North America. Uralian orogeny in Europe/Asia tapers off. Altaid orogeny in Asia. Hunter-Bowen Orogeny on Australian continent begins (c. 260–225 Ma), forming the MacDonnell Ranges. | 254.14 ± 0.07 * | |
Wuchiapingian | 259.51 ± 0.21 * | |||||
Guadalupian | Capitanian | 264.28 ± 0.16 * | ||||
Wordian | 266.9 ± 0.4 * | |||||
Roadian | 273.01 ± 0.14 * | |||||
Cisuralian | Kungurian | 283.5 ± 0.6 | ||||
Artinskian | 290.1 ± 0.26 * | |||||
Sakmarian | 293.52 ± 0.17 * | |||||
Asselian | 298.9 ± 0.15 * | |||||
Carboniferous [note 9] |
Pennsylvanian [note 10] |
Gzhelian | Winged insects radiate suddenly; some (esp. Protodonata and Palaeodictyoptera) of them as well some millipedes and scorpions become very large. First coal forests (scale trees, ferns, club trees, giant horsetails, Cordaites, etc.). Higher atmospheric oxygen levels. Ice Age continues to the Early Permian. Goniatites, brachiopods, bryozoa, bivalves, and corals plentiful in the seas and oceans. First woodlice. Testate forams proliferate. Euramerica collides with Gondwana and Siberia-Kazakhstania, the latter of which forms Laurasia and the Uralian orogeny. Variscan orogeny continues (these collisions created orogenies, and ultimately Pangaea). Amphibians (e.g. temnospondyls) spread in Euramerica, with some becoming the first amniotes. Carboniferous Rainforest Collapse occurs, initiating a dry climate which favors amniotes over amphibians. Amniotes diversify rapidly into synapsids, parareptiles, cotylosaurs, protorothyridids and diapsids. Rhizodonts remained common before they died out by the end of the period. First sharks. | 303.7 | ||
Kasimovian | 307 ± 0.1 | |||||
Moscovian | 315.2 ± 0.2 | |||||
Bashkirian | 323.2 * | |||||
Mississippian [note 10] |
Serpukhovian | Large lycopodian primitive trees flourish and amphibious eurypterids live amid coal-forming coastal swamps, radiating significantly one last time. First gymnosperms. First holometabolous, paraneopteran, polyneopteran, odonatopteran and ephemeropteran insects and first barnacles. First five-digited tetrapods (amphibians) and land snails. In the oceans, bony and cartilaginous fishes are dominant and diverse; echinoderms (especially crinoids and blastoids) abundant. Corals, bryozoans, orthoceridans, goniatites and brachiopods (Productida, Spiriferida, etc.) recover and become very common again, but trilobites and nautiloids decline. Glaciation in East Gondwana continues from Late Devonian. Tuhua Orogeny in New Zealand tapers off. Some lobe finned fish called rhizodonts become abundant and dominant in freshwaters. Siberia collides with a different small continent, Kazakhstania. | 330.9 ± 0.2 | |||
Viséan | 346.7 ± 0.4 * | |||||
Tournaisian | 358.9 ± 0.4 * | |||||
Devonian | Upper/Late | Famennian | First lycopods, ferns, seed plants (seed ferns, from earlier progymnosperms), first trees (the progymnosperm Archaeopteris), and first winged insects (palaeoptera and neoptera). Strophomenid and atrypid brachiopods, rugose and tabulate corals, and crinoids are all abundant in the oceans. First fully coiled cephalopods (Ammonoidea and Nautilida, independently) with the former group very abundant (especially goniatites). Trilobites and ostracoderms decline, while jawed fishes (placoderms, lobe-finned and ray-finned bony fish, and acanthodians and early cartilaginous fish) proliferate. Some lobe finned fish transform into digited fishapods, slowly becoming amphibious. The last non-trilobite artiopods die off. First decapods (like prawns) and isopods. Pressure from jawed fishes cause eurypterids to decline and some cephalopods to lose their shells while anomalocarids vanish. "Old Red Continent" of Euramerica persists after forming in the Caledonian orogeny. Beginning of Acadian Orogeny for Anti-Atlas Mountains of North Africa, and Appalachian Mountains of North America, also the Antler, Variscan, and Tuhua orogenies in New Zealand. A series of extinction events, including the massive Kellwasser and Hangenberg ones, wipe out many acritarchs, corals, sponges, molluscs, trilobites, eurypterids, graptolites, brachiopods, crinozoans (e.g. all cystoids), and fish, including all placoderms and ostracoderms. | 372.2 ± 1.6 * | ||
Frasnian | 382.7 ± 1.6 * | |||||
Middle | Givetian | 387.7 ± 0.8 * | ||||
Eifelian | 393.3 ± 1.2 * | |||||
Lower/Early | Emsian | 407.6 ± 2.6 * | ||||
Pragian | 410.8 ± 2.8 * | |||||
Lochkovian | 419.2 ± 3.2 * | |||||
Silurian | Pridoli | Ozone layer thickens. First vascular plants and fully terrestrialized arthropods: myriapods, hexapods (including insects), and arachnids. Eurypterids diversify rapidly, becoming widespread and dominant. Cephalopods continue to flourish. True jawed fishes, along with ostracoderms, also roam the seas. Tabulate and rugose corals, brachiopods (Pentamerida, Rhynchonellida, etc.), cystoids and crinoids all abundant. Trilobites and molluscs diverse; graptolites not as varied. Three minor extinction events. Some echinoderms go extinct. Beginning of Caledonian Orogeny (collision between Laurentia, Baltica and one of the formerly small Gondwanan terranes) for hills in England, Ireland, Wales, Scotland, and the Scandinavian Mountains. Also continued into Devonian period as the Acadian Orogeny, above (thus Euramerica forms). Taconic Orogeny tapers off. Icehouse period ends late in this period after starting in Late Ordovician. Lachlan Orogeny on Australian continent tapers off. | 423 ± 2.3 * | |||
Ludlow | Ludfordian | 425.6 ± 0.9 * | ||||
Gorstian | 427.4 ± 0.5 * | |||||
Wenlock | Homerian | 430.5 ± 0.7 * | ||||
Sheinwoodian | 433.4 ± 0.8 * | |||||
Llandovery | Telychian | 438.5 ± 1.1 * | ||||
Aeronian | 440.8 ± 1.2 * | |||||
Rhuddanian | 443.8 ± 1.5 * | |||||
Ordovician | Upper/Late | Hirnantian | The Great Ordovician Biodiversification Event occurs as plankton increase in number: invertebrates diversify into many new types (especially brachiopods and molluscs; e.g. long straight-shelled cephalopods like the long lasting and diverse Orthocerida). Early corals, articulate brachiopods (Orthida, Strophomenida, etc.), bivalves, cephalopods (nautiloids), trilobites, ostracods, bryozoans, many types of echinoderms (blastoids, cystoids, crinoids, sea urchins, sea cucumbers, and star-like forms, etc.), branched graptolites, and other taxa all common. Acritarchs still persist and common. Cephalopods become dominant and common, with some trending toward a coiled shell. Anomalocarids decline. Mysterious tentaculitans appear. First eurypterids and ostracoderm fish appear, the latter probably giving rise to the jawed fish at the end of the period. First uncontroversial terrestrial fungi and fully terrestrialized plants. Ice age at the end of this period, as well as a series of mass extinction events, killing off some cephalopods and many brachiopods, bryozoans, echinoderms, graptolites, trilobites, bivalves, corals and conodonts. | 445.2 ± 1.4 * | ||
Katian | 453 ± 0.7 * | |||||
Sandbian | 458.4 ± 0.9 * | |||||
Middle | Darriwilian | 467.3 ± 1.1 * | ||||
Dapingian | 470 ± 1.4 * | |||||
Lower/Early | Floian (formerly Arenig) |
477.7 ± 1.4 * | ||||
Tremadocian | 485.4 ± 1.9 * | |||||
Cambrian | Furongian | Stage 10 | Major diversification of (fossils mainly show bilaterian) life in the Cambrian Explosion as oxygen levels increase. Numerous fossils; most modern animal phyla (including arthropods, molluscs, annelids, echinoderms, hemichordates and chordates) appear. Reef-building archaeocyathan sponges initially abundant, then vanish. Stromatolites replace them, but quickly fall prey to the Agronomic revolution, when some animals started burrowing through the microbial mats (affecting some other animals as well). First artiopods (including trilobites), priapulid worms, inarticulate brachiopods (unhinged lampshells), hyoliths, bryozoans, graptolites, pentaradial echinoderms (e.g. blastozoans, crinozoans and eleutherozoans), and numerous other animals. Anomalocarids are dominant and giant predators, while many Ediacaran fauna die out. Crustaceans and molluscs diversify rapidly. Prokaryotes, protists (e.g., forams), algae and fungi continue to present day. First vertebrates from earlier chordates. Petermann Orogeny on the Australian continent tapers off (550–535 Ma). Ross Orogeny in Antarctica. Delamerian Orogeny (c. 514–490 Ma) on Australian continent. Some small terranes split off from Gondwana. Atmospheric CO2 content roughly 15 times present-day (Holocene) levels (6000 ppm compared to today's 400 ppm)[80][note 8] Arthropods and streptophyta start colonizing land. 3 extinction events occur 517, 502 & 488 Ma, the first and last of which wipe out many of the anomalocarids, artiopods, hyoliths, brachiopods, molluscs, and conodonts (early jawless vertebrates). | ~489.5 | ||
Jiangshanian | ~494 * | |||||
Paibian | ~497 * | |||||
Miaolingian | Guzhangian | ~500.5 * | ||||
Drumian | ~504.5 * | |||||
Wuliuan | ~509 | |||||
Series 2 | Stage 4 | ~514 | ||||
Stage 3 | ~521 | |||||
Terreneuvian | Stage 2 | ~529 | ||||
Fortunian | ~538.8 ± 0.2 * | |||||
Proterozoic | Neoproterozoic | Ediacaran | Good fossils of primitive animals. Ediacaran biota flourish worldwide in seas, possibly appearing after an explosion, possibly caused by a large-scale oxidation event.[85] First vendozoans (unknown affinity among animals), cnidarians and bilaterians. Enigmatic vendozoans include many soft-jellied creatures shaped like bags, disks, or quilts (like Dickinsonia). Simple trace fossils of possible worm-like Trichophycus, etc.Taconic Orogeny in North America. Aravalli Range orogeny in Indian subcontinent. Beginning of Pan-African Orogeny, leading to the formation of the short-lived Ediacaran supercontinent Pannotia, which by the end of the period breaks up into Laurentia, Baltica, Siberia and Gondwana. Petermann Orogeny forms on Australian continent. Beardmore Orogeny in Antarctica, 633–620 Ma. Ozone layer forms. An increase in oceanic mineral levels. | ~635 * | ||
Cryogenian | Possible "Snowball Earth" period. Fossils still rare. Late Ruker / Nimrod Orogeny in Antarctica tapers off. First uncontroversial animal fossils. First hypothetical terrestrial fungi[86] and streptophyta.[87] | ~720 [note 11] | ||||
Tonian | Finall assembly of Rodinia supercontinent occurs in early Tonian, with breakup beginning c. 800 Ma. Sveconorwegian orogeny ends. Grenville Orogeny tapers off in North America. Lake Ruker / Nimrod Orogeny in Antarctica, 1,000 ± 150 Ma. Edmundian Orogeny (c. 920–850 Ma), Gascoyne Complex, Western Australia. Deposition of Adelaide Superbasin and Centralian Superbasin begins on Australian continent. First hypothetical animals (from holozoans) and terrestrial algal mats. Many endosymbiotic events concerning red and green algae occur, transferring plastids to ochrophyta (e.g. diatoms, brown algae), dinoflagellates, cryptophyta, haptophyta, and euglenids (the events may have begun in the Mesoproterozoic)[88] while the first retarians (e.g. forams) also appear: eukaryotes diversify rapidly, including algal, eukaryovoric and biomineralized forms. Trace fossils of simple multi-celled eukaryotes. | 1000 [note 11] | ||||
Mesoproterozoic | Stenian | Narrow highly metamorphic belts due to orogeny as Rodinia forms, surrounded by the Pan-African Ocean. Sveconorwegian orogeny starts. Late Ruker / Nimrod Orogeny in Antarctica possibly begins. Musgrave Orogeny (c. 1,080–), Musgrave Block, Central Australia. Stromatolites decline as algae proliferate. | 1200 [note 11] | |||
Ectasian | Platform covers continue to expand. Algal colonies in the seas. Grenville Orogeny in North America. Columbia breaks up. | 1400 [note 11] | ||||
Calymmian | Platform covers expand. Barramundi Orogeny, McArthur Basin, Northern Australia, and Isan Orogeny, c. 1,600 Ma, Mount Isa Block, Queensland. First archaeplastidans (the first eukaryotes with plastids from cyanobacteria; e.g. red and green algae) and opisthokonts (giving rise to the first fungi and holozoans). Acritarchs (remains of marine algae possibly) start appearing in the fossil record. | 1600 [note 11] | ||||
Paleoproterozoic | Statherian | First uncontroversial eukaryotes: protists with nuclei and endomembrane system. Columbia forms as the second undisputed earliest supercontinent. Kimban Orogeny in Australian continent ends. Yapungku Orogeny on Yilgarn craton, in Western Australia. Mangaroon Orogeny, 1,680–1,620 Ma, on the Gascoyne Complex in Western Australia. Kararan Orogeny (1,650 Ma), Gawler Craton, South Australia. Oxygen levels drop again. | 1800 [note 11] | |||
Orosirian | The atmosphere becomes much more oxygenic while more cyanobacterial stromatolites appear. Vredefort and Sudbury Basin asteroid impacts. Much orogeny. Penokean and Trans-Hudsonian Orogenies in North America. Early Ruker Orogeny in Antarctica, 2,000–1,700 Ma. Glenburgh Orogeny, Glenburgh Terrane, Australian continent c. 2,005–1,920 Ma. Kimban Orogeny, Gawler craton in Australian continent begins. | 2050 [note 11] | ||||
Rhyacian | Bushveld Igneous Complex forms. Huronian glaciation. First hypothetical eukaryotes. Multicellular Francevillian biota. Kenorland disassembles. | 2300 [note 11] | ||||
Siderian | Great Oxidation Event (due to cyanobacteria) increases oxygen. Sleaford Orogeny on Australian continent, Gawler Craton 2,440–2,420 Ma. | 2500 [note 11] | ||||
Archean | Neoarchean | Stabilization of most modern cratons; possible mantle overturn event. Insell Orogeny, 2,650 ± 150 Ma. Abitibi greenstone belt in present-day Ontario and Quebec begins to form, stabilizes by 2,600 Ma. First uncontroversial supercontinent, Kenorland, and first terrestrial prokaryotes. | 2800 [note 11] | |||
Mesoarchean | First stromatolites (probably colonial phototrophic bacteria, like cyanobacteria). Oldest macrofossils. Humboldt Orogeny in Antarctica. Blake River Megacaldera Complex begins to form in present-day Ontario and Quebec, ends by roughly 2,696 Ma. | 3200 [note 11] | ||||
Paleoarchean | Prokaryotic archaea (e.g. methanogens) and bacteria (e.g. cyanobacteria) diversify rapidly, along with early viruses. First known phototrophic bacteria. Oldest definitive microfossils. First microbial mats. Oldest cratons on Earth (such as the Canadian Shield and the Pilbara Craton) may have formed during this period.[note 12] Rayner Orogeny in Antarctica. | 3600 [note 11] | ||||
Eoarchean | First uncontroversial living organisms: at first protocells with RNA-based genes around 4000 Ma, after which true cells (prokaryotes) evolve along with proteins and DNA-based genes around 3800 Ma. The end of the Late Heavy Bombardment. Napier Orogeny in Antarctica, 4,000 ± 200 Ma. | 4031 [note 11] | ||||
Hadean [note 13] |
Formation of protolith of the oldest known rock (Acasta Gneiss) c. 4,031 to 3,580 Ma.[89][90] Possible first appearance of plate tectonics. First hypothetical life forms. End of the Early Bombardment Phase. Oldest known mineral (Zircon, 4,404 ± 8 Ma).[91] Asteroids and comets bring water to Earth, forming the first oceans. Formation of Moon (4,533 to 4,527 Ma), probably from a giant impact. Formation of Earth (4,570 to 4,567.17 Ma) | ~4567.3 ± 0.16 [note 11] |
Non-Earth based geologic time scales
Some other planets and satellites in the Solar System have sufficiently rigid structures to have preserved records of their own histories, for example, Venus, Mars and the Earth's Moon. Dominantly fluid planets, such as the gas giants, do not comparably preserve their history. Apart from the Late Heavy Bombardment, events on other planets probably had little direct influence on the Earth, and events on Earth had correspondingly little effect on those planets. Construction of a time scale that links the planets is, therefore, of only limited relevance to the Earth's time scale, except in a Solar System context. The existence, timing, and terrestrial effects of the Late Heavy Bombardment are still a matter of debate.[note 14]
Lunar (selenological) time scale
The geologic history of Earth's Moon has been divided into a time scale based on geomorphological markers, namely impact cratering, volcanism, and erosion. This process of dividing the Moon's history in this manner means that the time scale boundaries do not imply fundamental changes in geological processes, unlike Earth's geologic time scale. Five geologic systems/periods (Pre-Nectarian, Nectarian, Imbrian, Eratosthenian, Copernican), with the Imbrian divided into two series/epochs (Early and Late) were defined in the latest Lunar geologic time scale.[92] The Moon is unique in the Solar System that is the only other body which we have rock samples with a known geological context.
![](http://upload.wikimedia.org/wikipedia/en/timeline/rqgvwx9mhj95lj57eva0a98t8ypxloi.png)
Martian geologic time scale
The geological history of Mars has been divided into two alternate time scales. The first time scale for Mars was developed by studying the impact crater densities on the Martian surface. Through this method four periods have been defined, the Pre-Noachian (~4,500–4,100 Ma), Noachian (~4,100–3,700 Ma), Hesperian (~3,700–3,000 Ma), and Amazonian (~3,000 Ma to present).[93][94]
![](http://upload.wikimedia.org/wikipedia/en/timeline/qet6aufoz6py1mu8mqq7qxqakgkq7df.png)
Epochs:
![](http://upload.wikimedia.org/wikipedia/en/timeline/l9mdbu2kk36h4dwzxwhwkvq47h8t0cb.png)
A second time scale based on mineral alteration observed by the OMEGA spectrometer on-board the Mars Express. Using this method, three periods were defined, the Phyllocian (~4,500–4,000 Ma), Theiikian (~4,000–3,500 Ma), and Siderikian (~3,500 Ma to present). [95]
![](http://upload.wikimedia.org/wikipedia/en/timeline/ell5m8tawqvpfmeygbgb4dgf8bskzpu.png)
See also
- Age of the Earth
- Cosmic calendar
- Deep time
- Evolutionary history of life
- Formation and evolution of the Solar System
- Geological history of Earth
- Geology of Mars
- Geon (geology)
- Graphical timeline of the universe
- History of the Earth
- History of geology
- History of paleontology
- List of fossil sites
- List of geochronologic names
- Logarithmic timeline
- Lunar geologic timescale
- Martian geologic timescale
- Natural history
- New Zealand geologic time scale
- Prehistoric life
- Timeline of the Big Bang
- Timeline of evolution
- Timeline of the geologic history of the United States
- Timeline of human evolution
- Timeline of natural history
- Timeline of paleontology
Notes
- ^ It is now known that not all sedimentary layers are deposited purely horizontally, but this principle is still a useful concept.
- ^ Time spans of geologic time units vary broadly, and there is no numeric limitation on the time span they can represent. They are limited by the time span of the higher rank unit they belong to, and to the chronostratigraphic boundaries they are defined by.
- ^ a b c Precambrian or pre-Cambrian is an informal geological term for time before the Cambrian period
- ^ a b The Tertiary is a now obsolete geologic system/period spanning from 66 Ma to 2.6 Ma. It has no exact equivalent in the modern ICC, but is approximately equivalent to the merged Palaeogene and Neogene systems/periods.
- ^ a b Geochronometric date for the Ediacaran has been adjusted to reflect ICC v2022/02 as the formal definition for the base of the Cambrian has not changed.
- ^ Kratian time span is not given in the article. It lies within the Neoarchean, and prior to the Siderian. The position shown here is an arbitrary division.
- ^ The dates and uncertainties quoted are according to the International Commission on Stratigraphy International Chronostratigraphic chart (v2022/02). A * indicates boundaries where a Global Boundary Stratotype Section and Point has been internationally agreed upon.
- ^ a b c d For more information on this, see Atmosphere of Earth#Evolution of Earth's atmosphere, Carbon dioxide in the Earth's atmosphere, and climate change. Specific graphs of reconstructed CO2 levels over the past ~550, 65, and 5 million years can be seen at File:Phanerozoic Carbon Dioxide.png, File:65 Myr Climate Change.png, File:Five Myr Climate Change.png, respectively.
- ^ The Mississippian and Pennsylvanian are official sub-systems/sub-periods.
- ^ a b This is divided into Lower/Early, Middle, and Upper/Late series/epochs
- ^ a b c d e f g h i j k l m n Defined by absolute age (Global Standard Stratigraphic Age).
- ^ The age of the oldest measurable craton, or continental crust, is dated to 3,600–3,800 Ma.
- ^ Though commonly used, the Hadean is not formally ratified by the ICS.
- ^ Not enough is known about extra-solar planets for worthwhile speculation.
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Further reading
- Aubry, Marie-Pierre; Van Couvering, John A.; Christie-Blick, Nicholas; Landing, Ed; Pratt, Brian R.; Owen, Donald E.; Ferrusquia-Villafranca, Ismael (2009). "Terminology of geological time: Establishment of a community standard". Stratigraphy. 6 (2): 100–105. doi:10.7916/D8DR35JQ.
- Gradstein, F. M.; Ogg, J. G. (2004). "A Geologic Time scale 2004 – Why, How and Where Next!" (PDF). Lethaia. 37 (2): 175–181. doi:10.1080/00241160410006483. Archived from the original (PDF) on 17 April 2018. Retrieved 30 November 2018.
- Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (2004). A Geologic Time Scale 2004. Cambridge, UK: Cambridge University Press. ISBN 978-0-521-78142-8. Retrieved 18 November 2011.
- Gradstein, Felix M.; Ogg, James G.; Smith, Alan G.; Bleeker, Wouter; Laurens, Lucas, J. (June 2004). "A new Geologic Time Scale, with special reference to Precambrian and Neogene". Episodes. 27 (2): 83–100. doi:10.18814/epiiugs/2004/v27i2/002.
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: CS1 maint: multiple names: authors list (link) - Ialenti, Vincent (28 September 2014). "Embracing 'Deep Time' Thinking". NPR. NPR Cosmos & Culture.
- Ialenti, Vincent (21 September 2014). "Pondering 'Deep Time' Could Inspire New Ways To View Climate Change". NPR. NPR Cosmos & Culture.
- Knoll, Andrew H.; Walter, Malcolm R.; Narbonne, Guy M.; Christie-Blick, Nicholas (30 July 2004). "A New Period for the Geologic Time Scale" (PDF). Science. 305 (5684): 621–622. doi:10.1126/science.1098803. PMID 15286353. S2CID 32763298. Retrieved 18 November 2011.
- Levin, Harold L. (2010). "Time and Geology". The Earth Through Time. Hoboken, New Jersey: John Wiley & Sons. ISBN 978-0-470-38774-0. Retrieved 18 November 2011.
- Montenari, Michael (2016). Stratigraphy and Timescales (1st ed.). Amsterdam: Academic Press (Elsevier). ISBN 978-0-12-811549-7.
External links
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/df/Wikibooks-logo-en-noslogan.svg/40px-Wikibooks-logo-en-noslogan.svg.png)
- The current version of the International Chronostratigraphic Chart can be found at stratigraphy.org/chart
- Interactive version of the International Chronostratigraphic Chart is found at stratigraphy.org/timescale
- A list of current Global Boundary Stratotype and Section Points is found at stratigraphy.org/gssps
- NASA: Geologic Time
- GSA: Geologic Time Scale
- British Geological Survey: Geological Timechart
- GeoWhen Database
- National Museum of Natural History – Geologic Time
- SeeGrid: Geological Time Systems Archived 23 July 2008 at the Wayback Machine Information model for the geologic time scale
- Exploring Time from Planck Time to the lifespan of the universe
- Episodes, Gradstein, Felix M. et al. (2004) A new Geologic Time Scale, with special reference to Precambrian and Neogene, Episodes, Vol. 27, no. 2 June 2004 (pdf)
- Lane, Alfred C, and Marble, John Putman 1937. Report of the Committee on the measurement of geologic time
- Lessons for Children on Geologic Time
- Deep Time – A History of the Earth : Interactive Infographic
- Geology Buzz: Geologic Time Scale