Geologic time scale: Difference between revisions
The Earwig (talk | contribs) →Table of geologic time: merge in {{Geologic time scale}} per Wikipedia:Templates for discussion/Log/2015 July 29#Template:Geologic time scale |
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A service providing a [[Resource Description Framework]]/[[Web Ontology Language]] representation of the timescale 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/|accessdate=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|accessdate=2014-08-03|title=SPARQL endpoint for CGI timescale service|author=Simon J. D. Cox}}</ref><ref>{{cite web|url=http://dx.doi.org/10.1007/s12145-014-0170-6|accessdate=2014-08-03|title=A geologic timescale ontology and service|author=Simon J. D. Cox, Stephen M. Richard}}</ref> |
A service providing a [[Resource Description Framework]]/[[Web Ontology Language]] representation of the timescale 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/|accessdate=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|accessdate=2014-08-03|title=SPARQL endpoint for CGI timescale service|author=Simon J. D. Cox}}</ref><ref>{{cite web|url=http://dx.doi.org/10.1007/s12145-014-0170-6|accessdate=2014-08-03|title=A geologic timescale ontology and service|author=Simon J. D. Cox, Stephen M. Richard}}</ref> |
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{{Template for discussion/dated|page=Geologic time scale|link=Wikipedia:Templates for discussion/Log/2015 July 29#Template:Geologic time scale|help=off}}<div style="clear:both; width:100%; margin-left:auto; margin-right:auto" class="NavFrame"> |
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{{Geologic time scale}} |
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<div class="NavHead" style="background-color:#ccccff">{{Navbar-collapsible | [[Geologic time scale]] | Geologic time scale}}</div> |
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{| class="wikitable" style="clear:both;margin:0; font-size:95%" |
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! [[Supereon (geology)|Supereon]] |
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! [[Eon (geology)|Eon]] |
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! [[Era (geology)|Era]] |
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! [[Period (geology)|Period]]<ref name="faunal-stages">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 {{cite web|url=http://flatpebble.nceas.ucsb.edu/cgi-bin/bridge.pl?action=startScale| title=The Paleobiology Database| accessdate=2006-03-19}}</ref> |
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! [[Epoch (geology)|Epoch]] |
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! [[Age (geology)|Age]]<ref name="uncertain-dates" /> |
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! Major events |
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! Start, million years ago<ref 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]] 2015 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.</ref> |
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|rowspan="100" style="background:#ffffff"| n/a<ref>References to the "Post-Cambrian Supereon" are not universally accepted, and therefore must be considered unofficial.</ref> |
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|rowspan="100" style="background:{{period color|Phanerozoic}}"| [[Phanerozoic]] |
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|rowspan="22" style="background:{{period color|Cenozoic}}"| [[Cenozoic]]<ref name="cenozoic-division">Historically, the [[Cenozoic]] has been divided up into the [[Quaternary]] and [[Tertiary]] sub-eras, as well as the [[Neogene]] and [[Paleogene]] periods. The [http://www.stratigraphy.org/upload/ISChart2009.pdf 2009 version of the ICS time chart] recognizes a slightly extended Quaternary as well as the Paleogene and a truncated Neogene, the Tertiary having been demoted to informal status.</ref> |
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|rowspan="5" style="background:{{period color|Quaternary}}"| [[Quaternary]] |
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|style="background:{{period color|Holocene}}"| [[Holocene]] |
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|style="background:{{period color|Holocene}}"| |
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[[Chronozone|chrons]]: [[Subatlantic]]{{·}}[[Subboreal]]{{·}}[[Atlantic (period)|Atlantic]]{{·}}[[Boreal (period)|Boreal]]{{·}}[[Preboreal]] |
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|rowspan="1" | [[Quaternary glaciation|Quaternary Ice Age]] recedes, and the current [[interglacial]] begins; rise of human [[civilization]]. [[Sahara]] forms from savannah, and [[agriculture]] begins. [[Stone Age]] cultures give way to [[Bronze Age]] (3300 BC) and [[Iron Age]] (1200 BC), giving rise to [[Synoptic table of the principal old world prehistoric cultures|many pre-historic cultures]] throughout the world. [[Little Ice Age]] ([[stadial]]) causes brief cooling in [[Northern Hemisphere]] from 1400 to 1850. Following the [[Industrial Revolution]], [[Atmosphere of Earth|atmospheric]] [[Carbon dioxide in the Earth's atmosphere|CO<sub>2</sub>]] levels rise from around 280 [[parts per million]] volume (ppmv) to the current level of 400<ref>"NASA Scientists React to 400 ppm Carbon Milestone". Retrieved 2014-01-15 [http://climate.nasa.gov/400ppmquotes/]</ref> ppmv.<ref name="Royer">{{cite journal |last=Royer |title={{CO2}}-forced climate thresholds during the Phanerozoic |journal=Geochimica et Cosmochimica Acta |volume=70 |pages=5665–75 |year=2006 |url=http://droyer.web.wesleyan.edu/PhanCO2%28GCA%29.pdf |format=PDF |doi=10.1016/j.gca.2005.11.031 |first1=Dana L. |issue=23|bibcode = 2006GeCoA..70.5665R }}</ref><ref name="atmospheric-carbon-dioxide">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 CO<sub>2</sub> 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.</ref> |
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|style="background:{{period color|Holocene}}"| {{Period start|holocene}}<ref name="holocene">The start time for the [[Holocene]] epoch is here given as [[Upper Paleolithic|11,700]] [[before present|years ago]]. For further discussion of the dating of this epoch, see [[Holocene]].</ref> |
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|rowspan="4" style="background:{{period color|Pleistocene}}"| [[Pleistocene]] |
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|style="background:{{period color|Upper Pleistocene}}"| [[Late Pleistocene|Late]] (locally [[Tarantian]]{{·}}[[Tyrrhenian Stage|Tyrrhenian]]{{·}}[[Eemian]]{{·}}[[Sangamonian Stage|Sangamonian]]) |
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|rowspan="4"| Flourishing and then extinction of many large [[mammal]]s ([[Pleistocene megafauna]]). Evolution of anatomically modern [[human]]s. [[Last glacial period|Quaternary Ice Age]] continues with [[Glacial period|glaciations]] and [[interstadial]]s (and the accompanying fluctuations from 100 to 300 ppmv in [[Atmosphere of Earth|atmospheric]] CO<sub>2</sub> levels<ref name="Royer" /><ref name="atmospheric-carbon-dioxide" />), further intensification of [[Greenhouse and Icehouse Earth|Icehouse Earth]] conditions, roughly 1.6 [[Year#SI prefix multipliers|Ma]]. [[Last glacial maximum]] (30000 [[before present|years ago]]), [[last glacial period]] (18000–15000 years ago). Dawn of human [[Lower Paleolithic#Cultures|stone-age cultures]], with [[Middle Paleolithic#Cultures|increasing technical complexity]] relative to previous ice age cultures, such as [[Upper Paleolithic#Cultures|engravings and clay statues]] (e.g. [[Venus of Lespugue]]), particularly in the [[Mediterranean]] and Europe. [[Lake Toba]] [[supervolcano]] erupts 75000 years before present, causing a [[volcanic winter]] that [[Toba catastrophe theory|pushes humanity to the brink of extinction]]. Pleistocene ends with [[Oldest Dryas]], [[Older Dryas]]/[[Allerød Oscillation|Allerød]] and [[Younger Dryas]] climate events, with Younger Dryas forming the boundary with the Holocene. |
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|style="background:{{period color|upper Pleistocene}}"| {{Period start|Late pleistocene}} |
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|style="background:{{period color|Middle Pleistocene}}"| [[Middle Pleistocene|Middle]] (formerly Ionian) |
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|style="background:{{period color|Middle Pleistocene}}"| {{Period start|middle pleistocene}} |
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|style="background:{{period color|Calabrian}}"| [[Early Pleistocene|Calabrian]] |
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|style="background:{{period color|Calabrian}}"| {{Period start|calabrian}}<sup>*</sup> |
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|style="background:{{period color|Gelasian}}"| [[Gelasian]] |
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|style="background:{{period color|Gelasian}}"| {{Period start|gelasian}}<sup>*</sup> |
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|rowspan="8" style="background:{{period color|Neogene}}"| [[Neogene]] |
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|rowspan="2" style="background:{{period color|Pliocene}}"| [[Pliocene]] |
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|rowspan="1" style="background:{{period color|Piacenzian}}"| [[Piacenzian]]/[[Blancan]] |
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|rowspan="2"| Intensification of present [[Greenhouse and Icehouse Earth|Icehouse conditions]], [[Quaternary glaciation|present (Quaternary) ice age]] begins roughly 2.58 Ma; cool and dry [[climate]]. [[Australopithecine]]s, many of the existing genera of mammals, and recent [[mollusk]]s appear. ''[[Homo habilis]]'' appears. |
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|style="background:{{period color|Piacenzian}}"| {{Period start|piacenzian}}<sup>*</sup> |
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|style="background:{{period color|Zanclean}}"| [[Zanclean]] |
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|style="background:{{period color|Zanclean}}"| {{Period start|zanclean}}<sup>*</sup> |
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|rowspan="6" style="background:{{period color|Miocene}}"| [[Miocene]] |
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|style="background:{{period color|Messinian}}"| [[Messinian]] |
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|rowspan="6"| [[Greenhouse and Icehouse Earth|Moderate Icehouse climate]], punctuated by [[ice age]]s; [[Orogeny]] in [[Northern Hemisphere]]. Modern [[mammal]] and [[bird]] families become recognizable. [[Equidae|Horses]] and [[mastodon]]s diverse. [[Grass]]es become ubiquitous. First [[ape]]s appear (for reference see the article: "[[Sahelanthropus tchadensis]]"). [[Kaikoura Orogeny]] forms [[Southern Alps]] in New Zealand, continues today. Orogeny of the Alps in Europe slows, but continues to this day. [[Carpathian orogeny]] forms [[Carpathian Mountains]] in [[Central Europe|Central]] and [[Eastern Europe]]. [[Hellenic orogeny]] in Greece and Aegean Sea slows, but continues to this day. [[Middle Miocene Disruption]] occurs. Widespread forests slowly [[photosynthesis|draw in]] massive amounts of CO<sub>2</sub>, gradually lowering the level of atmospheric CO<sub>2</sub> from 650 ppmv down to around 100 ppmv.<ref name="Royer" /><ref name="atmospheric-carbon-dioxide" /> |
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|style="background:{{period color|Messinian}}"| {{Period start|messinian}}<sup>*</sup> |
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|style="background:{{period color|Tortonian}}"| [[Tortonian]] |
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|style="background:{{period color|Tortonian}}"| {{Period start|tortonian}}<sup>*</sup> |
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|style="background:{{period color|Serravallian}}"| [[Serravallian]] |
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|style="background:{{period color|Serravallian}}"| {{Period start|serravallian}}<sup>*</sup> |
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|style="background:{{period color|Langhian}}"| [[Langhian]] |
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|style="background:{{period color|Langhian}}"| {{Period start|langhian}} |
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|style="background:{{period color|Burdigalian}}"| [[Burdigalian]] |
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|style="background:{{period color|Burdigalian}}"| {{Period start|burdigalian}} |
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|style="background:{{period color|Aquitanian}}"| [[Aquitanian age|Aquitanian]] |
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|style="background:{{period color|Aquitanian}}"| {{Period start|aquitanian}}<sup>*</sup> |
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|rowspan="9" style="background:{{period color|Paleogene}}"| [[Paleogene]] |
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|rowspan="2" style="background:{{period color|Oligocene}}"| [[Oligocene]] |
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|style="background:{{period color|Chattian}}"| [[Chattian]] |
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|rowspan="2"| [[Greenhouse and Icehouse Earth|Warm but cooling climate]], moving towards Icehouse; Rapid [[evolution]] and diversification of fauna, especially [[mammal]]s. Major evolution and dispersal of modern types of [[flowering plant]]s |
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|style="background:{{period color|Chattian}}"| {{Period start|chattian}} |
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|style="background:{{period color|Rupelian}}"| [[Rupelian]] |
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|style="background:{{period color|Rupelian}}"| {{Period start|rupelian}}<sup>*</sup> |
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|rowspan="4" style="background:{{period color|Eocene}}"| [[Eocene]] |
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|style="background:{{period color|Priabonian}}"| [[Priabonian]] |
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|rowspan="4"| [[Greenhouse and Icehouse Earth|Moderate, cooling climate]]. Archaic [[mammal]]s (e.g. [[Creodont]]s, [[Condylarth]]s, [[Uintatheriidae|Uintatheres]], etc.) flourish and continue to develop during the epoch. Appearance of several "modern" mammal families. Primitive [[Cetacea|whales]] diversify. First [[grass]]es. Reglaciation of Antarctica and formation of its [[ice cap]]; [[Azolla event]] triggers [[ice age]], and the [[Greenhouse and Icehouse Earth|Icehouse Earth]] climate that would follow it to this day, from the settlement and decay of [[seafloor]] [[algae]] drawing in massive amounts of atmospheric [[carbon dioxide]],<ref name="Royer" /><ref name="atmospheric-carbon-dioxide" /> lowering it from 3800 [[parts per million|ppmv]] down to 650 ppmv. End of [[Laramide Orogeny|Laramide]] and [[Sevier orogeny|Sevier Orogenies]] of the [[Rocky Mountains]] in North America. [[Orogeny]] of the [[Alps]] in Europe begins. [[Hellenic Orogeny]] begins in Greece and [[Aegean Sea]]. |
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|style="background:{{period color|Priabonian}}"| {{Period start|priabonian}} |
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|style="background:{{period color|Bartonian}}"| [[Bartonian]] |
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|style="background:{{period color|Bartonian}}"| {{Period start|bartonian}} |
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|style="background:{{period color|Lutetian}}"| [[Lutetian]] |
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|style="background:{{period color|Lutetian}}"| {{Period start|lutetian}}<sup>*</sup> |
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|style="background:{{period color|Ypresian}}"| [[Ypresian]] |
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|style="background:{{period color|Ypresian}}"| {{Period start|ypresian}}<sup>*</sup> |
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|rowspan="3" style="background:{{period color|Paleocene}}"| [[Paleocene]] |
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|style="background:{{period color|Thanetian}}"| [[Thanetian]] |
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|rowspan="3"| [[Greenhouse and Icehouse Earth|Climate tropical]]. Modern [[plant]]s appear; [[Mammal]]s diversify into a number of primitive lineages following the extinction of the dinosaurs. First large mammals (up to [[bear]] or small [[hippopotamus|hippo]] size). [[Alpine orogeny]] in Europe and Asia begins. [[Indian Subcontinent]] collides with Asia 55 [[Year#SI prefix multipliers|Ma]], [[Geology of the Himalaya|Himalayan Orogeny]] starts between 52 and 48 [[Year#SI prefix multipliers|Ma]]. |
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|style="background:{{period color|Thanetian}}"| {{Period start|thanetian}}<sup>*</sup> |
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|style="background:{{period color|Selandian}}"| [[Selandian]] |
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|style="background:{{period color|Selandian}}"| {{Period start|selandian}}<sup>*</sup> |
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|style="background:{{period color|Danian}}"| [[Danian]] |
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|style="background:{{period color|Danian}}"| {{Period start|danian}}<sup>*</sup> |
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|rowspan="30" style="background:{{period color|Mesozoic}}"| [[Mesozoic]] |
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|rowspan="12" style="background:{{period color|Cretaceous}}" | [[Cretaceous]] |
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|rowspan="6" style="background:{{period color|Late Cretaceous}}"| [[Late Cretaceous|Late]] |
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|style="background:{{period color|Maastrichtian}}"| [[Maastrichtian]] |
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|rowspan="12"| [[Flowering plant]]s proliferate, along with new types of [[insect]]s. More modern [[teleost]] fish begin to appear. [[Ammonoidea]], [[Belemnoidea|belemnites]], [[rudist]] [[Bivalvia|bivalve]]s, [[Echinoidea|echinoid]]s and [[Porifera|sponges]] all common. Many new types of [[dinosaur]]s (e.g. [[Tyrannosauridae|Tyrannosaurs]], [[Titanosauridae|Titanosaurs]], [[Hadrosauridae|duck bills]], and [[Ceratopsidae|horned dinosaurs]]) evolve on land, as do [[Eusuchia]] ([[Crocodilia|modern crocodilians]]); and [[mosasaur]]s and modern [[shark]]s appear in the sea. Primitive [[bird]]s gradually replace [[pterosaurs]]. [[Monotremes]], [[marsupial]]s and [[Eutheria|placental]] mammals appear. Break up of [[Gondwana]]. Beginning of [[Laramide Orogeny|Laramide]] and [[Sevier Orogeny|Sevier Orogenies]] of the [[Rocky Mountains]]. [[Atmosphere of Earth|atmospheric]] CO<sub>2</sub> close to present-day levels. |
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|style="background:{{period color|Maastrichtian}}"| {{Period start|maastrichtian}} ± 0.2<sup>*</sup> |
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|style="background:{{period color|Campanian}}"| [[Campanian]] |
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|style="background:{{period color|Campanian}}"| {{Period start|campanian}} ± 0.2 |
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|style="background:{{period color|Santonian}}"| [[Santonian]] |
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|style="background:{{period color|Santonian}}"| {{Period start|santonian}} ± 0.5<sup>*</sup> |
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|style="background:{{period color|Coniacian}}"| [[Coniacian]] |
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|style="background:{{period color|Coniacian}}"| {{Period start|coniacian}} ± 0.3 |
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|style="background:{{period color|Turonian}}"| [[Turonian]] |
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|style="background:{{period color|Turonian}}"| {{Period start|turonian}}<sup>*</sup> |
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|style="background:{{period color|Cenomanian}}"| [[Cenomanian]] |
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|style="background:{{period color|Cenomanian}}"| {{Period start|cenomanian}}<sup>*</sup> |
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|rowspan="6" style="background:{{period color|Early Cretaceous}}"| [[Early Cretaceous|Early]] |
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|style="background:{{period color|Albian}}"| [[Albian]] |
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|style="background:{{period color|Albian}}"| ~{{Period start|albian}} |
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|style="background:{{period color|Aptian}}"| [[Aptian]] |
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|style="background:{{period color|Aptian}}"| ~{{Period start|aptian}} |
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|style="background:{{period color|Barremian}}"| [[Barremian]] |
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|style="background:{{period color|Barremian}}"| ~{{Period start|barremian}} |
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|style="background:{{period color|Hauterivian}}"| [[Hauterivian]] |
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|style="background:{{period color|Hauterivian}}"| ~{{Period start|hauterivian}} |
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|style="background:{{period color|Valanginian}}"| [[Valanginian]] |
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|style="background:{{period color|Valanginian}}"| ~{{Period start|valanginian}} |
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|style="background:{{period color|Berriasian}}"| [[Berriasian]] |
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|style="background:{{period color|Berriasian}}"| ~{{Period start|berriasian}} |
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|rowspan="11" style="background:{{period color|Jurassic}}"| [[Jurassic]] |
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|rowspan="3" style="background:{{period color|Late Jurassic}}"| [[Late Jurassic|Late]] |
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|style="background:{{period color|Tithonian}}"| [[Tithonian]] |
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|rowspan="11"| [[Gymnosperm]]s (especially [[conifer]]s, [[Bennettitales]] and [[cycad]]s) and [[fern]]s common. Many types of [[dinosaur]]s, such as [[sauropod]]s, [[carnosaur]]s, and [[stegosaur]]s. Mammals common but small. First [[bird]]s and [[Squamata|lizards]]. [[Ichthyosaur]]s and [[plesiosaur]]s diverse. [[Bivalvia|Bivalve]]s, [[Ammonite]]s and [[Belemnoidea|belemnites]] abundant. [[Sea urchin]]s very common, along with [[crinoid]]s, starfish, [[Porifera|sponges]], and [[Terebratulida|terebratulid]] and [[Rhynchonellida|rhynchonellid]] [[brachiopod]]s. Breakup of [[Pangaea]] into [[Gondwana]] and [[Laurasia]]. [[Nevadan orogeny]] in North America. [[Rangitata Orogeny|Rantigata]] and [[Cimmerian Orogeny|Cimmerian Orogenies]] taper off. Atmospheric CO<sub>2</sub> levels 4–5 times the present day levels (1200–1500 ppmv, compared to today's 385 ppmv<ref name="Royer" /><ref name="atmospheric-carbon-dioxide" />). |
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|style="background:{{period color|Tithonian}}"| {{Period start|tithonian}} ± 0.9 |
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|style="background:{{period color|Kimmeridgian}}"| [[Kimmeridgian]] |
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|style="background:{{period color|Kimmeridgian}}"| {{Period start|kimmeridgian}} ± 1.0 |
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|style="background:{{period color|Oxfordian}}"| [[Oxfordian stage|Oxfordian]] |
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|style="background:{{period color|Oxfordian}}"| {{Period start|oxfordian}} ± 1.0 |
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|rowspan="4" style="background:{{period color|Middle Jurassic}}"| [[Middle Jurassic|Middle]] |
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|style="background:{{period color|Callovian}}"| [[Callovian]] |
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|style="background:{{period color|Callovian}}"| {{Period start|callovian}} ± 1.2 |
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|style="background:{{period color|Bathonian}}"| [[Bathonian]] |
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|style="background:{{period color|Bathonian}}"| {{Period start|bathonian}} ± 1.3<sup>*</sup> |
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|style="background:{{period color|Bajocian}}"| [[Bajocian]] |
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|style="background:{{period color|Bajocian}}"| {{Period start|bajocian}} ± 1.4<sup>*</sup> |
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|style="background:{{period color|Aalenian}}"| [[Aalenian]] |
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|style="background:{{period color|Aalenian}}"| {{Period start|aalenian}} ± 1.0<sup>*</sup> |
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|rowspan="4" style="background:{{period color|Early Jurassic}}"| [[Early Jurassic|Early]] |
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|style="background:{{period color|Toarcian}}"| [[Toarcian]] |
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|style="background:{{period color|Toarcian}}"| {{Period start|toarcian}} ± 0.7<sup>*</sup> |
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|style="background:{{period color|Pliensbachian}}"| [[Pliensbachian]] |
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|style="background:{{period color|Pliensbachian}}"| {{Period start|pliensbachian}} ± 1.0<sup>*</sup> |
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|style="background:{{period color|Sinemurian}}"| [[Sinemurian]] |
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|style="background:{{period color|Sinemurian}}"| {{Period start|sinemurian}} ± 0.3<sup>*</sup> |
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|style="background:{{period color|Hettangian}}"| [[Hettangian]] |
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|style="background:{{period color|Hettangian}}"| {{Period start|hettangian}} ± 0.2<sup>*</sup> |
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|rowspan="7" style="background:{{period color|Triassic}}"| [[Triassic]] |
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|rowspan="3" style="background:{{period color|Late Triassic}}"| [[Late Triassic|Late]] |
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|style="background:{{period color|Rhaetian}}"| [[Rhaetian]] |
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|rowspan="7"| [[Archosaur]]s dominant on land as [[dinosaur]]s, in the oceans as [[Ichthyosaur]]s and [[nothosaur]]s, and in the air as [[pterosaur]]s. [[Cynodont]]s become smaller and more mammal-like, while first [[mammal]]s and [[crocodilia]] appear. ''[[Dicroidium]]''flora common on land. Many large aquatic [[temnospondyli|temnospondyl]] amphibians. [[Ammonite|Ceratitic ammonoids]] extremely common. [[Scleractinia|Modern corals]] and [[teleost]] fish appear, as do many modern [[insect]] clades. [[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 [[Year#SI prefix multipliers|Ma]]) |
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|style="background:{{period color|Rhaetian}}"| ~{{Period start|rhaetian}} |
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|style="background:{{period color|Norian}}"| [[Norian]] |
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|style="background:{{period color|Norian}}"| ~{{Period start|norian}} |
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|style="background:{{period color|Carnian}}"| [[Carnian]] |
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|style="background:{{period color|Carnian}}"| ~{{Period start|carnian}}<sup>*</sup> |
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|- |
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|rowspan="2" style="background:{{period color|Middle Triassic}}"| [[Middle Triassic|Middle]] |
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|style="background:{{period color|Ladinian}}"| [[Ladinian]] |
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|style="background:{{period color|Ladinian}}"| ~{{Period start|ladinian}}<sup>*</sup> |
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|- |
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|style="background:{{period color|Anisian}}"| [[Anisian]] |
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|style="background:{{period color|Anisian}}"| {{Period start|anisian}} |
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|- |
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|rowspan="2" style="background:{{period color|Early Triassic}}"| [[Early Triassic|Early]] |
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|style="background:{{period color|Olenekian}}"| [[Olenekian]] |
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|style="background:{{period color|Olenekian}}"| {{Period start|olenekian}} |
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|- |
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|style="background:{{period color|Induan}}"| [[Induan]] |
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|style="background:{{period color|Induan}}"| {{Period start|induan}} ± 0.06<sup>*</sup> |
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|- |
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|rowspan="48" style="background:{{period color|Paleozoic}}"| [[Paleozoic]] |
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|rowspan="9" style="background:{{period color|Permian}}"| [[Permian]] |
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|rowspan="2" style="background:{{period color|Lopingian}}"| [[Lopingian]] |
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|style="background:{{period color|Changhsingian}}"| [[Changhsingian]] |
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|rowspan="9"| [[Landmass]]es unite into [[supercontinent]] [[Pangaea]], creating the [[Appalachian Mountains|Appalachian]]s. End of Permo-Carboniferous glaciation. [[Synapsida|Synapsid]] [[Reptilia|reptile]]s ([[pelycosaur]]s and [[therapsid]]s) become plentiful, while [[parareptile]]s and [[temnospondyli|temnospondyl]] [[Amphibian|amphibians]] remain common. In the mid-Permian, [[coal]]-age flora are replaced by [[Conifer cone|cone]]-bearing [[gymnosperm]]s (the first true [[seed plants]]) and by the first true [[moss]]es. [[Beetles]] and [[Fly|flies]] evolve. Marine life flourishes in warm shallow reefs; [[Productida|productid]] and [[Spiriferida|spiriferid]] brachiopods, bivalves, [[foraminifera|foram]]s, and [[orthocerid|ammonoid]]s all abundant. [[Permian-Triassic extinction event]] occurs 251 [[Year#SI prefix multipliers|Ma]]: 95% of life on Earth becomes extinct, including all [[trilobite]]s, [[graptolite]]s, and [[blastoid]]s. [[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 [[Year#SI prefix multipliers|Ma]]), forming the [[MacDonnell Ranges]]. |
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|style="background:{{period color|Changhsingian}}"| {{Period start|changhsingian}} ± 0.07<sup>*</sup> |
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|- |
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|style="background:{{period color|Wuchiapingian}}"| [[Wuchiapingian]] |
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|style="background:{{period color|Wuchiapingian}}"| {{Period start|wuchiapingian}} ± 0.4<sup>*</sup> |
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|- |
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|rowspan="3" style="background:{{period color|Guadalupian}}"| [[Guadalupian]] |
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|style="background:{{period color|Capitanian}}"| [[Capitanian]] |
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|style="background:{{period color|Capitanian}}"| {{Period start|capitanian}} ± 0.4<sup>*</sup> |
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|- |
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|style="background:{{period color|Wordian}}"| [[Wordian]]/Kazanian |
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|style="background:{{period color|Wordian}}"| {{Period start|wordian}} ± 0.5<sup>*</sup> |
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|- |
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|style="background:{{period color|Roadian}}"| [[Roadian]]/Ufimian |
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|style="background:{{period color|Roadian}}"| {{Period start|roadian}} ± 0.5<sup>*</sup> |
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|- |
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|rowspan="4" style="background:{{period color|Cisuralian}}"| [[Cisuralian]] |
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|style="background:{{period color|Kungurian}}"| [[Kungurian]] |
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|style="background:{{period color|Kungurian}}"| {{Period start|kungurian}} ± 0.6 |
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|- |
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|style="background:{{period color|Artinskian}}"| [[Artinskian]] |
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|style="background:{{period color|Artinskian}}"| {{Period start|artinskian}} ± 0.26 |
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|- |
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|style="background:{{period color|Sakmarian}}"| [[Sakmarian]] |
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|style="background:{{period color|Sakmarian}}"| {{Period start|sakmarian}} ± 0.18 |
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|- |
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|style="background:{{period color|Asselian}}"| [[Asselian]] |
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|style="background:{{period color|Asselian}}"| {{Period start|asselian}} ± 0.15<sup>*</sup> |
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|- |
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|rowspan="7" style="background:{{period color|Carboniferous}}"| [[Carboniferous|Carbon-<br />iferous]]<ref name="carboniferous">In North America, the Carboniferous is subdivided into [[Mississippian age|Mississippian]] and [[Pennsylvanian (geology)|Pennsylvanian]] Periods.</ref> |
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|rowspan="4" style="background:{{period color|Pennsylvanian}}"| [[Pennsylvanian (geology)|Pennsylvanian]] |
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|style="background:{{period color|Gzhelian}}"| [[Gzhelian]] |
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|rowspan="4"| [[Pterygota|Winged insects]] radiate suddenly; some (esp. [[Protodonata]] and [[Palaeodictyoptera]]) are quite large. [[Amphibian]]s common and diverse. First [[reptile]]s and [[coal]] forests ([[Lepidodendron|scale tree]]s, ferns, [[Sigillaria|club tree]]s, [[Calamites|giant horsetail]]s, ''[[Cordaites]]'', etc.). Highest-ever [[Atmosphere of Earth|atmospheric]] [[oxygen]] levels. [[Goniatite]]s, brachiopods, bryozoa, bivalves, and corals plentiful in the seas and oceans. Testate [[foram]]s proliferate. [[Uralian orogeny]] in Europe and Asia. [[Variscan orogeny]] occurs towards middle and late Mississippian Periods. |
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|style="background:{{period color|Gzhelian}}"| {{Period start|gzhelian}} ± 0.1 |
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|- |
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|style="background:{{period color|Kasimovian}}"| [[Kasimovian]] |
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|style="background:{{period color|Kasimovian}}"| {{Period start|kasimovian}} ± 0.1 |
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|- |
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|style="background:{{period color|Moscovian}}"| [[Moscovian (Carboniferous)|Moscovian]] |
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|style="background:{{period color|Moscovian}}"| {{Period start|moscovian}} ± 0.2 |
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|- |
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|style="background:{{period color|Bashkirian}}"| [[Bashkirian]] |
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|style="background:{{period color|Bashkirian}}"| {{Period start|bashkirian}} ± 0.4<sup>*</sup> |
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|- |
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|rowspan="3" style="background:{{period color|Mississippian}}"|[[Mississippian age|Mississippian]] |
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|style="background:{{period color|Serpukhovian}}"| [[Serpukhovian]] |
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|rowspan="3"| Large [[Lycopodiophyta|primitive tree]]s, first [[Tetrapoda|land vertebrate]]s, and amphibious [[eurypterid|sea-scorpion]]s live amid [[coal]]-forming coastal [[brackish water|swamp]]s. Lobe-finned [[rhizodont]]s are dominant big fresh-water predators. In the oceans, early [[Chondrichthyes|shark]]s are common and quite diverse; [[echinoderm]]s (especially [[crinoid]]s and [[blastoid]]s) abundant. [[Coral]]s, [[bryozoa]], [[Goniatitida|goniatite]]s and brachiopods ([[Productida]], [[Spiriferida]], etc.) very common, but [[Trilobita|trilobite]]s and [[nautiloid]]s decline. [[Glaciation]] in East [[Gondwana]]. [[Mayor Island/Tuhua|Tuhua Orogeny]] in New Zealand tapers off. |
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|style="background:{{period color|Serpukhovian}}"| {{Period start|serpukhovian}} ± 0.2 |
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|- |
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|style="background:{{period color|visean}}"| [[Viséan]] |
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|style="background:{{period color|visean}}"| {{Period start|visean}} ± 0.4<sup>*</sup> |
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|- |
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|style="background:{{period color|Tournaisian}}"| [[Tournaisian]] |
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|style="background:{{period color|Tournaisian}}"| {{Period start|tournaisian}} ± 0.4<sup>*</sup> |
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|- |
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|rowspan="7" style="background:{{period color|Devonian}}"| [[Devonian]] |
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|rowspan="2" style="background:{{period color|Late Devonian}}"| [[Late Devonian|Late]] |
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|style="background:{{period color|Famennian}}"| [[Famennian]] |
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|rowspan="7"| First [[Lycopodiopsida|clubmoss]]es, [[Equisetophyta|horsetail]]s and [[fern]]s appear, as do the first [[seed]]-bearing plants ([[progymnosperm]]s), first [[tree]]s (the progymnosperm ''[[Archaeopteris]]''), and first (wingless) [[insect]]s. [[Strophomenida|Strophomenid]] and [[Atrypida|atrypid]] [[brachiopod]]s, [[Rugosa|rugose]] and [[Tabulata|tabulate]] corals, and [[crinoid]]s are all abundant in the oceans. [[Goniatite]] [[Ammonite|ammonoids]] are plentiful, while squid-like [[Coleoidea|coleoids]] arise. Trilobites and armoured agnaths decline, while jawed fishes ([[Placodermi|placoderm]]s, [[Sarcopterygii|lobe-finned]] and [[Osteichthyes|ray-finned]] fish, and early [[Chondrichthyes|sharks]]) rule the seas. First [[amphibian]]s still aquatic. "Old Red Continent" of [[Euramerica]]. 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 Orogeny]] in New Zealand. |
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|style="background:{{period color|Famennian}}"| {{Period start|famennian}} ± 1.6<sup>*</sup> |
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|- |
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|style="background:{{period color|Frasnian}}"| [[Frasnian]] |
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|style="background:{{period color|Frasnian}}"| {{Period start|frasnian}} ± 1.6<sup>*</sup> |
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|- |
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|rowspan="2" style="background:{{period color|Middle Devonian}}"| [[Middle Devonian|Middle]] |
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|style="background:{{period color|Givetian}}"| [[Givetian]] |
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|style="background:{{period color|Givetian}}"| {{Period start|givetian}} ± 0.8<sup>*</sup> |
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|- |
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|style="background:{{period color|Eifelian}}"| [[Eifelian]] |
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|style="background:{{period color|Eifelian}}"| {{Period start|eifelian}} ± 1.2<sup>*</sup> |
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|- |
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|rowspan="3" style="background:{{period color|Early Devonian}}"| [[Early Devonian|Early]] |
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|style="background:{{period color|Emsian}}"| [[Emsian]] |
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|style="background:{{period color|Emsian}}"| {{Period start|emsian}} ± 2.6<sup>*</sup> |
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|- |
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|style="background:{{period color|Pragian}}"| [[Pragian]] |
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|style="background:{{period color|Pragian}}"| {{Period start|pragian}} ± 2.8<sup>*</sup> |
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|- |
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|style="background:{{period color|Lochkovian}}"| [[Lochkovian]] |
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|style="background:{{period color|Lochkovian}}"| {{Period start|lochkovian}} ± 3.2<sup>*</sup> |
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|- |
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|rowspan="8" style="background:{{period color|Silurian}}"| [[Silurian]] |
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|colspan="2" style="background:{{period color|Pridoli}}"| [[Pridoli epoch|Pridoli]] |
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|rowspan="8"| First [[Vascular plant]]s (the [[rhyniophytes]] and their relatives), first [[millipede]]s and [[Arthropleurida|arthropleurid]]s on land. First [[jawed fish]]es, as well as many [[ostracoderm|armoured]] [[agnatha|jawless fish]], populate the seas. [[Eurypterid|Sea-scorpions]] reach large size. [[Tabulate coral|Tabulate]] and [[Rugosa|rugose]] corals, [[brachiopod]]s (''Pentamerida'', [[Rhynchonellida]], etc.), and [[crinoid]]s all abundant. [[Trilobite]]s and [[mollusk]]s diverse; [[graptolite]]s not as varied. Beginning of [[Caledonian Orogeny]] for hills in England, Ireland, Wales, Scotland, and the [[Scandinavian Mountains]]. Also continued into Devonian period as the [[Acadian Orogeny]], above. [[Taconic Orogeny]] tapers off. [[Lachlan Orogeny]] on [[Australia (continent)|Australian continent]] tapers off. |
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|style="background:{{period color|Pridoli}}"| {{Period start|pridoli}} ± 2.3<sup>*</sup> |
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|- |
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|rowspan="2" style="background:{{period color|Ludlow}}"| [[Ludlow epoch|Ludlow]]/[[Cayugan]] |
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|style="background:{{period color|Ludfordian}}"| [[Ludfordian]] |
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|style="background:{{period color|Ludfordian}}"| {{Period start|ludfordian}} ± 0.9<sup>*</sup> |
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|- |
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|style="background:{{period color|Gorstian}}"| [[Gorstian]] |
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|style="background:{{period color|Gorstian}}"| {{Period start|gorstian}} ± 0.5<sup>*</sup> |
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|- |
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|rowspan="2" style="background:{{period color|Wenlock}}"| [[Wenlock epoch|Wenlock]] |
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|style="background:{{period color|Homerian}}"| [[Homerian]]/<br>[[Lockportian]] |
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|style="background:{{period color|Homerian}}"| {{Period start|homerian}} ± 0.7<sup>*</sup> |
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|- |
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|style="background:{{period color|Sheinwoodian}}"| [[Sheinwoodian]]/<br>[[Tonawandan]] |
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|style="background:{{period color|Sheinwoodian}}"| {{Period start|sheinwoodian}} ± 0.8<sup>*</sup> |
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|- |
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|rowspan="3" style="background:{{period color|Llandovery}}"| [[Llandovery epoch|Llandovery]]/<br />[[Silurian|Alexandrian]] |
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|style="background:{{period color|Telychian}}"| [[Telychian]]/<br>[[Ontarian]] |
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|style="background:{{period color|Telychian}}"| {{Period start|telychian}} ± 1.1<sup>*</sup> |
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|- |
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|style="background:{{period color|Aeronian}}"| [[Aeronian]] |
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|style="background:{{period color|Aeronian}}"| {{Period start|aeronian}} ± 1.2<sup>*</sup> |
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|- |
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|style="background:{{period color|Rhuddanian}}"| [[Rhuddanian]] |
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|style="background:{{period color|Rhuddanian}}"| {{Period start|rhuddanian}} ± 1.5<sup>*</sup> |
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|- |
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|rowspan="7" style="background:{{period color|Ordovician}}"| [[Ordovician]] |
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|rowspan="3" style="background:{{period color|Late Ordovician}}"| [[Late Ordovician|Late]] |
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|style="background:{{period color|Hirnantian}}"| [[Hirnantian]] |
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|rowspan="7"| [[Invertebrate]]s diversify into many new types (e.g., long [[orthoconic|straight-shelled]] [[orthocerida|cephalopods]]). Early [[coral]]s, articulate [[brachiopod]]s (''Orthida'', ''Strophomenida'', etc.), [[Bivalvia|bivalves]], [[nautiloid]]s, [[trilobite]]s, [[ostracod]]s, [[bryozoa]], many types of [[echinoderms]] ([[crinoid]]s, [[Cystoidea|cystoids]], [[Asteroidea|starfish]], etc.), branched [[graptolite]]s, and other taxa all common. [[Conodont]]s (early [[plankton]]ic [[vertebrate]]s) appear. First [[Embryophyte|green plant]]s and [[fungus|fungi]] on land. Ice age at end of period. |
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|style="background:{{period color|Hirnantian}}"| {{Period start|hirnantian}} ± 1.4<sup>*</sup> |
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|- |
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|style="background:{{period color|Katian}}"| [[Katian]] |
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|style="background:{{period color|Katian}}"| {{Period start|katian}} ± 0.7<sup>*</sup> |
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|- |
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|style="background:{{period color|Sandbian}}"| [[Sandbian]] |
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|style="background:{{period color|Sandbian}}"| {{Period start|sandbian}} ± 0.9<sup>*</sup> |
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|- |
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|rowspan="2" style="background:{{period color|Middle Ordovician}}"| [[Middle Ordovician|Middle]] |
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|style="background:{{period color|Darriwilian}}"| [[Darriwilian]] |
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|style="background:{{period color|Darriwilian}}"| {{Period start|darriwilian}} ± 1.1<sup>*</sup> |
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|- |
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|style="background:{{period color|Dapingian}}"| [[Dapingian]] |
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|style="background:{{period color|Dapingian}}"| {{Period start|dapingian}} ± 1.4<sup>*</sup> |
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|- |
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|rowspan="2" style="background:{{period color|Early Ordovician}}"| [[Early Ordovician|Early]] |
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|style="background:{{period color|Floian}}"| [[Floian]]<br />(formerly [[Arenig]]) |
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|style="background:{{period color|Floian}}"| {{Period start|floian}} ± 1.4<sup>*</sup> |
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|- |
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|style="background:{{period color|Tremadocian}}"| [[Tremadocian]] |
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|style="background:{{period color|Tremadocian}}"| {{Period start|tremadocian}} ± 1.9<sup>*</sup> |
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|- |
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|rowspan="10" style="background:{{period color|Cambrian}}"| [[Cambrian]] |
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|rowspan="3" style="background:{{period color|Furongian}}"| [[Furongian]] |
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|style="background:{{period color|Stage 10}}"| [[Cambrian Stage 10|Stage 10]] |
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|rowspan="10"| Major diversification of life in the [[Cambrian Explosion]]. Numerous fossils; most modern [[Animalia|animal]] [[Phylum|phyla]] appear. First [[chordate]]s appear, along with a number of extinct, problematic phyla. Reef-building [[Archaeocyatha]] abundant; then vanish. [[Trilobite]]s, [[priapulid]] worms, [[Porifera|sponges]], inarticulate [[brachiopod]]s (unhinged lampshells), and many other animals numerous. [[Anomalocarid]]s are giant predators, while many Ediacaran fauna die out. [[Prokaryote]]s, [[protist]]s (e.g., [[foram]]s), [[fungus|fungi]] and [[algae]] continue to present day. [[Gondwana]] emerges. [[Petermann Orogeny]] on the [[Australia (continent)|Australian continent]] tapers off (550–535 [[Year#SI prefix multipliers|Ma]]). Ross Orogeny in Antarctica. [[Adelaide Geosyncline|Adelaide Geosyncline (Delamerian Orogeny)]], majority of orogenic activity from 514–500 [[Year#SI prefix multipliers|Ma]]. [[Lachlan Orogeny]] on [[Australia (continent)|Australian continent]], c. 540–440 [[Year#SI prefix multipliers|Ma]]. [[Atmosphere of Earth|Atmospheric]] CO<sub>2</sub> content roughly 20–35 times present-day ([[Holocene]]) levels (6000 ppmv compared to today's 385 ppmv)<ref name="Royer" /><ref name="atmospheric-carbon-dioxide" /> |
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|style="background:{{period color|Stage 10}}"| ~489.5 |
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|- |
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|style="background:{{period color|Jiangshanian}}"| [[Jiangshanian]] |
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|style="background:{{period color|Jiangshanian}}"| ~494<sup>*</sup> |
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|- |
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|style="background:{{period color|Paibian}}"| [[Paibian]] |
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|style="background:{{period color|Paibian}}"| ~{{Period start|paibian}}<sup>*</sup> |
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|- |
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|rowspan="3" style="background:{{period color|Series 3}}"| [[Cambrian Series 3|Series 3]] |
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|style="background:{{period color|Guzhangian}}"| [[Guzhangian]] |
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|style="background:{{period color|Guzhangian}}"| ~{{Period start|guzhangian}}<sup>*</sup> |
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|- |
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|style="background:{{period color|Drumian}}"| [[Drumian]] |
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|style="background:{{period color|Drumian}}"| ~{{Period start|drumian}}<sup>*</sup> |
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|- |
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|style="background:{{period color|Stage 5}}"| [[Cambrian Stage 5|Stage 5]] |
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|style="background:{{period color|Stage 5}}"| ~{{Period start|cambrian stage 5}} |
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|- |
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|rowspan="2" style="background:{{period color|Series 2}}"| [[Cambrian Series 2|Series 2]] |
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|style="background:{{period color|Stage 4}}"| [[Cambrian Stage 4|Stage 4]] |
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|style="background:{{period color|Stage 4}}"| ~{{Period start|cambrian stage 4}} |
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|- |
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|style="background:{{period color|Stage 3}}"| [[Cambrian Stage 3|Stage 3]] |
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|style="background:{{period color|Stage 3}}"| ~{{Period start|cambrian stage 3}} |
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|- |
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|rowspan="2" style="background:{{period color|Terreneuvian}}"| [[Terreneuvian]] |
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|style="background:{{period color|Stage 2}}"| [[Cambrian Stage 2|Stage 2]] |
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|style="background:{{period color|Stage 2}}"| ~{{Period start|cambrian stage 2}} |
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|- |
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|style="background:{{period color|Fortunian}}"| [[Fortunian]] |
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|style="background:{{period color|Fortunian}}"| {{Period start|fortunian}} ± 1.0<sup>*</sup> |
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|- |
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|rowspan="18" style="background:{{period color|Precambrian}}"| [[Precambrian|Precambrian]]<ref name="aka-cryptozoic">The [[Precambrian]] is also known as Cryptozoic.</ref> |
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|rowspan="10" style="background:{{period color|Proterozoic}}"| [[Proterozoic|Proterozoic]]<ref name="Precambrian-Time">The [[Proterozoic]], [[Archean]] and [[Hadean]] are often collectively referred to as the [[Precambrian|Precambrian Time]] or sometimes, also the Cryptozoic.</ref> |
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|rowspan="3" style="background:{{period color|Neoproterozoic}}"| [[Neoproterozoic|Neoproterozoic]]<ref name="Precambrian-Time" /> |
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|style="background:{{period color|Ediacaran}}"| [[Ediacaran]] |
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|colspan="3"| Good [[fossil]]s of the first [[Metazoa|multi-celled animal]]s. [[Ediacaran biota]] flourish worldwide in seas. Simple [[trace fossil]]s of possible worm-like ''[[Trichophycus pedum|Trichophycus]]'', etc. First [[Porifera|sponge]]s and [[Trilobita|trilobitomorph]]s. Enigmatic forms include many soft-jellied creatures shaped like bags, disks, or quilts (like''[[Dickinsonia]]''). [[Taconic Orogeny]] in North America. [[Aravalli Range]] [[orogeny]] in [[Indian Subcontinent]]. Beginning of [[Petermann Orogeny]] on [[Australia (continent)|Australian continent]]. Beardmore Orogeny in Antarctica, 633–620 [[Year#SI prefix multipliers|Ma]]. |
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|style="background:{{period color|Ediacaran}}"| ~{{Period start|ediacaran}}<sup>*</sup> |
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|- |
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|style="background:{{period color|Cryogenian}}"| [[Cryogenian]] |
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|colspan="3"| Possible "[[Snowball Earth]]" period. [[Fossil]]s still rare. [[Rodinia]] landmass begins to break up. Late Ruker / Nimrod Orogeny in Antarctica tapers of<bef. |
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|style="background:{{period color|Cryogenian}}"| {{Period start|cryogenian}}<ref name="absolute-age">Defined by absolute age ([[Global Standard Stratigraphic Age]]).</ref> |
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|- |
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|style="background:{{period color|Tonian}}"| [[Tonian]] |
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|colspan="3"| [[Rodinia]] supercontinent persists. [[Trace fossil]]s of simple [[multicellular|multi-celled]] [[Eukaryota|eukaryote]]s. First radiation of [[dinoflagellate]]-like [[acritarch]]s. [[Grenville Orogeny]] tapers off in North America. [[Pan-African orogeny]] in Africa. Lake Ruker / Nimrod Orogeny in Antarctica, 1000 ± 150 [[Year#SI prefix multipliers|Ma]]. Edmundian Orogeny (c. 920 – 850 [[Year#SI prefix multipliers|Ma]]), [[Gascoyne Complex]], Western Australia. [[Adelaide Geosyncline]] laid down on [[Australia (continent)|Australian continent]], beginning of [[Adelaide Geosyncline|Adelaide Geosyncline (Delamerian Orogeny)]] in that continent. |
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|style="background:{{period color|Tonian}}"| {{Period start|tonian}}<ref name="absolute-age" /> |
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|- |
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|rowspan="3" style="background:{{period color|Mesoproterozoic}}"| [[Mesoproterozoic|Mesoproterozoic]]<ref name="Precambrian-Time" /> |
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|style="background:{{period color|Stenian}}"| [[Stenian]] |
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|colspan="3"| Narrow highly [[Metamorphic rock|metamorphic]] belts due to [[orogeny]] as [[Rodinia]] forms. Late Ruker / Nimrod Orogeny in Antarctica possibly begins. Musgrave Orogeny (c. 1080 [[Year#SI prefix multipliers|Ma]]), [[Musgrave Block]], [[Central Australia]]. |
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|style="background:{{period color|Stenian}}"| {{Period start|stenian}}<ref name="absolute-age" /> |
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|- |
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|style="background:{{period color|Ectasian}}"| [[Ectasian]] |
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|colspan="3"| [[Platform cover]]s continue to expand. [[Green algae]] [[colony (biology)|colonies]] in the seas. [[Grenville Orogeny]] in North America. |
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|style="background:{{period color|Ectasian}}"| {{Period start|ectasian}}<ref name="absolute-age" /> |
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|- |
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|style="background:{{period color|Calymmian}}"| [[Calymmian]] |
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|colspan="3"| [[Platform cover]]s expand. Barramundi Orogeny, [[McArthur Basin]], [[Northern Australia]], and Isan Orogeny, [[circa|c.]]1600 [[Year#SI prefix multipliers|Ma]], Mount Isa Block, Queensland |
|||
|style="background:{{period color|Calymmian}}"| {{Period start|calymmian}}<ref name="absolute-age" /> |
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|- |
|||
|rowspan="4" style="background:{{period color|Paleoproterozoic}}"| [[Paleoproterozoic|Paleoproterozoic]]<ref name="Precambrian-Time" /> |
|||
|style="background:{{period color|Statherian}}"| [[Statherian]] |
|||
|colspan="3"| First [[Eukaryote|complex single-celled life]]: [[protist]]s with nuclei. [[Columbia (supercontinent)|Columbia]] is the primordial supercontinent. Kimban Orogeny in Australian continent ends. Yapungku Orogeny on [[Yilgarn craton]], in Western Australia. Mangaroon Orogeny, 1680–1620 [[Year#SI prefix multipliers|Ma]], on the [[Gascoyne Complex]] in Western Australia. Kararan Orogeny (1650– [[Year#SI prefix multipliers|Ma]]), Gawler Craton, [[South Australia]]. |
|||
|style="background:{{period color|Statherian}}"| {{Period start|statherian}}<ref name="absolute-age" /> |
|||
|- |
|||
|style="background:{{period color|Orosirian}}"| [[Orosirian]] |
|||
|colspan="3"| The [[Atmosphere of Earth|atmosphere]] becomes [[oxygen]]ic. [[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, 2000–1700 [[Year#SI prefix multipliers|Ma]]. Glenburgh Orogeny, [[Gascoyne Complex|Glenburgh Terrane]], [[Australia (continent)|Australian continent]] [[circa|c.]] 2005–1920 [[Year#SI prefix multipliers|Ma]]. Kimban Orogeny, [[Gawler craton]] in Australian continent begins. |
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|style="background:{{period color|Orosirian}}"| {{Period start|orosirian}}<ref name="absolute-age" /> |
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|- |
|||
|style="background:{{period color|Rhyacian}}"| [[Rhyacian]] |
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|colspan="3"| [[Bushveld Igneous Complex]] forms. [[Huronian]] glaciation. |
|||
|style="background:{{period color|Rhyacian}}"| {{Period start|rhyacian}}<ref name="absolute-age" /> |
|||
|- |
|||
|style="background:{{period color|Siderian}}"| [[Siderian]] |
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|colspan="3"| [[Oxygen catastrophe]]: [[banded iron formation]]s forms. Sleaford Orogeny on [[Australia (continent)|Australian continent]], [[Gawler Craton]] 2440–2420 [[Year#SI prefix multipliers|Ma]]. |
|||
|style="background:{{period color|Siderian}}"| {{Period start|siderian}}<ref name="absolute-age" /> |
|||
|- |
|||
|rowspan="4" style="background:{{period color|Archean}}"| [[Archean]]<ref name="Precambrian-Time" /> |
|||
|style="background:{{period color|Neoarchean}}"| [[Neoarchean]]<ref name="Precambrian-Time" /> |
|||
|colspan="4"| Stabilization of most modern [[craton]]s; possible [[Mantle (geology)|mantle]] overturn event. Insell Orogeny, 2650 ± 150 [[Year#SI prefix multipliers|Ma]]. [[Abitibi greenstone belt]] in present-day [[Ontario]] and [[Quebec]] begins to form, stabilizes by 2600 [[Year#SI prefix multipliers|Ma]]. |
|||
|style="background:{{period color|Neoarchean}}"| {{Period start|neoarchean}}<ref name="absolute-age" /> |
|||
|- |
|||
|style="background:{{period color|Mesoarchean}}"| [[Mesoarchean]]<ref name="Precambrian-Time" /> |
|||
|colspan="4"| First [[stromatolite]]s (probably [[colony (biology)|colonial]] [[cyanobacteria]]). Oldest [[macrofossil]]s. Humboldt Orogeny in Antarctica. [[Blake River Megacaldera Complex]] begins to form in present-day [[Ontario]] and [[Quebec]], ends by roughly 2696 [[Year#SI prefix multipliers|Ma]]. |
|||
|style="background:{{period color|Mesoarchean}}"| {{Period start|mesoarchean}}<ref name="absolute-age" /> |
|||
|- |
|||
|style="background:{{period color|Paleoarchean}}"| [[Paleoarchean]]<ref name="Precambrian-Time" /> |
|||
|colspan="4"| First known [[phototroph|oxygen-producing]] [[bacteria]]. Oldest definitive [[microfossils]]. Oldest [[craton]]s on Earth (such as the [[Canadian Shield]] and the [[Pilbara Craton]]) may have formed during this period.<ref name="Oldest-craton">The age of the oldest measurable [[craton]], or [[continental crust]], is dated to 3600–3800 Ma</ref> Rayner Orogeny in Antarctica. |
|||
|style="background:{{period color|Paleoarchean}}"| {{Period start|paleoarchean}}<ref name="absolute-age" /> |
|||
|- |
|||
|style="background:{{period color|Eoarchean}}"| [[Eoarchean]]<ref name="Precambrian-Time" /> |
|||
|colspan="4"| [[Prokaryote|Simple single-celled life]] (probably [[bacteria]] and [[archaea]]). Oldest probable [[microfossil]]s. |
|||
|style="background:{{period color|Eoarchean}}"| {{Period start|eoarchean}} |
|||
|- |
|||
|rowspan="4" style="background:{{period color|Hadean}}"| [[Hadean]]<ref name="Precambrian-Time" /><ref name="hadeon-not-formal">Though commonly used, the [[Hadean]] is not a formal eon 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.</ref> |
|||
|style="background:{{period color|Hadean}}"| [[Early Imbrian]]<ref name="Precambrian-Time" /><ref 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.</ref> |
|||
|colspan="4"| Indirect [[photosynthetic]] evidence (e.g., [[kerogen]]) of primordial life. This era overlaps the end of the [[Late Heavy Bombardment]] of the [[Inner Solar System|Inner]] [[Solar System]]. |
|||
|style="background:{{period color|Hadean}}"| ~4100 |
|||
|- |
|||
|style="background:{{period color|Hadean}}"| [[Nectarian]]<ref name="Precambrian-Time" /><ref name="Lunar-geologic-timescale-names" /> |
|||
|colspan="4"| 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. |
|||
|style="background:{{period color|Hadean}}"| ~4300 |
|||
|- |
|||
|style="background:{{period color|Hadean}}"| [[Basin Groups]]<ref name="Precambrian-Time" /><ref name="Lunar-geologic-timescale-names" /> |
|||
|colspan="4"| Oldest known rock (4030 [[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|author=Bowring, Samuel A.|journal=Contributions to Mineralogy and Petrology|volume=134|issue=1|pages=3|last2=Williams|first2=Ian S.|bibcode=1999CoMP..134....3B}} The oldest rock on Earth is the [[Acasta Gneiss]], and it dates to 4.03 Ga, located in the [[Northwest Territories]] of Canada.</ref> The first [[organism|life form]]s and [[self-replication|self-replicating]] [[RNA]] [[molecule]]s evolve around 4000 [[Year#SI prefix multipliers|Ma]], after the [[Late Heavy Bombardment]] ends on Earth. [[Napier Mountains|Napier]] Orogeny in Antarctica, 4000 ± 200 [[Year#SI prefix multipliers|Ma]]. |
|||
|style="background:{{period color|Hadean}}"| ~4500 |
|||
|- |
|||
|style="background:{{period color|Hadean}}"| [[Cryptic era|Cryptic]]<ref name="Precambrian-Time" /><ref name="Lunar-geologic-timescale-names" /> |
|||
|colspan="4"| Oldest known [[mineral]] ([[Zircon]], 4404 ± 8 [[Year#SI prefix multipliers|Ma]]).<ref name="geology-wisc-edu">[http://www.geology.wisc.edu/%7Evalley/zircons/Wilde2001Nature.pdf Geology.wisc.edu]</ref> Formation of [[Moon]] (4533 [[Year#SI prefix multipliers|Ma]]), probably from [[Giant impact hypothesis|giant impact]]. Formation of [[Earth]] (4567.17 to 4570 [[Year#SI prefix multipliers|Ma]]) |
|||
|style="background:{{period color|Hadean}}"| ~4567 |
|||
|}</div> |
|||
</div> |
|||
===Proposed Precambrian timeline=== |
===Proposed Precambrian timeline=== |
Revision as of 20:23, 6 August 2015
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/77/Geologic_Clock_with_events_and_periods.svg/400px-Geologic_Clock_with_events_and_periods.svg.png)
The geological time scale (GTS) is a system of chronological measurement that relates stratigraphy to time, and is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships between events that have occurred throughout Earth’s history. The table of geologic time spans presented here agrees with the nomenclature, dates and standard color codes set forth by the International Commission on Stratigraphy.
Evidence from radiometric dating indicates that Earth is about 4.54 billion years old. The geology or deep time of Earth’s past has been organized into various units according to events which took place in each period. Different spans of time on the GTS are usually delimited by changes in the composition of strata which correspond to them, indicating major geological or paleontological events, such as mass extinctions. 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 dinosaurs and many other groups of life. Older time spans which predate the reliable fossil record (before the Proterozoic Eon) are defined by the absolute age.
Terminology
Segments of rock (strata) in chronostratigraphy | Time spans in geochronology | Notes to geochronological units |
---|---|---|
Eonothem | Eon | 4 total, half a billion years or more |
Erathem | Era | 10 defined, several hundred million years |
System | Period | 22 defined, tens to ~one hundred million years |
Series | Epoch | 34 defined, tens of millions of years |
Stage | Age | 99 defined, millions of years |
Chronozone | Chron | subdivision of an age, not used by the ICS timescale |
The largest defined unit of time is the supereon, composed of eons. Eons are divided into eras, which are in turn divided into periods, epochs and ages. The terms eonothem, erathem, system, series, and stage are used to refer to the layers of rock that correspond to these periods of geologic time in Earth's history.
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.[3] The adjectives are capitalized when the subdivision is formally recognized, and lower case when not; thus "early Miocene" but "Early Jurassic."
Geologic units from the same time but different parts of the world often look different and contain different fossils, so the same period 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 succession of 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 horizons that can be used around the world.[4]
History and nomenclature of the time scale
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/79/Geological_time_spiral.png/220px-Geological_time_spiral.png)
![](http://upload.wikimedia.org/wikipedia/en/thumb/7/72/Geological_Time_Scale.png/220px-Geological_Time_Scale.png)
In Ancient Greece, Aristotle saw that fossils of seashells from rocks were similar to those found on the beach and inferred that the fossils were once part of living animals. He reasoned that the positions of land and sea had changed over long periods of time. Leonardo da Vinci concurred with Aristotle’s view that fossils were the remains of ancient life.[5]
The 11th-century Persian geologist Avicenna (Ibn Sina) and the 13th century Dominican bishop Albertus Magnus (Albert of Saxony) extended Aristotle's explanation into a theory of a petrifying fluid.[6] 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 in 1027.[7][8] The Chinese naturalist Shen Kuo (1031–1095) also recognized the concept of ‘deep time’.[9]
The principles underlying geologic (geological) time scales were later laid down by Nicholas Steno in the late 17th century. Steno argued that rock layers (or strata) are 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 to real rocks proved complex. Over the course of the 18th century geologists realized that:
- Sequences of strata were often 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.
The first serious attempts to formulate a geological 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 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) and "Quaternary" (now Pleistocene and Holocene) remained in use as names of geological periods well into the 20th century.
The Neptunist theories popular at this time (expounded by Werner) 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 before the Royal Society of Edinburgh in March and April 1785. It has been said that "as things appear from the perspective of the 20th century, James Hutton in those readings became the founder of modern geology".[10] 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 was called "Plutonist" in contrast to the "Neptunist" flood-oriented theory.
The identification of strata by the fossils they contained, pioneered by William Smith, Georges Cuvier, Jean d'Omalius d'Halloy, and Alexandre Brogniart 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 geological periods still used today.
The process was dominated by British geologists, and the names of the 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.[11] The "Devonian" was named for the English county of Devon, and the name "Carboniferous" was simply an adaptation of "the Coal Measures", the old British geologists’ term for the same set of strata. The "Permian" was named after Perm, 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 [trias] Error: {{Lang}}: text has italic markup (help) meaning triad) —red beds, capped by chalk, followed by black shales — that are found throughout Germany and Northwest Europe, called the ‘Trias’. The "Jurassic" was named by a French geologist Alexandre Brogniart 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 d’Omalius d’Halloy in 1822, using strata in the Paris basin[12] and named for the extensive beds of chalk (calcium carbonate deposited by the shells of marine invertebrates).
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 published the first global geological 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.[13]
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 various kinds of rates of change used in estimation were highly variable. While 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 with some even suggesting a virtually infinite age for Earth. 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 radioactivity in 1896 and the development of its geological applications through radiometric dating during the first half of the 20th century (pioneered by such geologists as Arthur Holmes) which allowed for more precise absolute dating of rocks, the ages of various rock strata and the age of Earth were the subject of considerable debate.
The first geologic time scale that included absolute dates was published in 1913 by the British geologist Arthur Holmes.[14] 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.[15]
In 1977, the Global Commission on Stratigraphy (now the International Commission on Stratigraphy) started an effort to define global references known as GSSP (Global Boundary Stratotype Sections and Points)for geologic periods and faunal stages. The commission's most recent work is described in the 2004 geologic time scale of Gradstein et al.[16] A UML model for how the timescale is structured, relating it to the GSSP, is also available.[17]
Condensed graphical timelines
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)
Table of geologic time
The following table summarizes the major events and characteristics of the periods of time making up the geologic time scale. As above, this time scale is based on the International Commission on Stratigraphy. (See lunar geologic timescale for a discussion of the geologic subdivisions of Earth's moon.) This table is arranged with the most recent geologic periods at the top, and the most ancient at the bottom. The height of each table entry does not correspond to the duration of each subdivision of time.
The content of the table is based on the current official geologic time scale of the International Commission on Stratigraphy,[1] with the epoch names altered to the early/late format from lower/upper as recommended by the ICS when dealing with chronostratigraphy.[3]
A service providing a Resource Description Framework/Web Ontology Language representation of the timescale is available through the Commission for the Management and Application of Geoscience Information GeoSciML project as a service[18] and at a SPARQL end-point.[19][20]
Supereon | Eon | Era | Period[21] | Epoch | Age[22] | Major events | Start, million years ago[22] |
---|---|---|---|---|---|---|---|
n/a[23] | Phanerozoic | Cenozoic[24] | Quaternary | Holocene |
chrons: Subatlantic · Subboreal · Atlantic · Boreal · Preboreal |
Quaternary Ice Age recedes, and the current interglacial begins; rise of human civilization. Sahara forms from savannah, and agriculture begins. Stone Age cultures give way to Bronze Age (3300 BC) and Iron Age (1200 BC), giving rise to many pre-historic cultures throughout the world. Little Ice Age (stadial) causes brief cooling in Northern Hemisphere from 1400 to 1850. Following the Industrial Revolution, atmospheric CO2 levels rise from around 280 parts per million volume (ppmv) to the current level of 400[25] ppmv.[26][27] | 0.0117[28] |
Pleistocene | Late (locally Tarantian · Tyrrhenian · Eemian · Sangamonian) | Flourishing and then extinction of many large mammals (Pleistocene megafauna). Evolution of anatomically modern humans. Quaternary Ice Age continues with glaciations and interstadials (and the accompanying fluctuations from 100 to 300 ppmv in atmospheric CO2 levels[26][27]), further intensification of Icehouse Earth conditions, roughly 1.6 Ma. Last glacial maximum (30000 years ago), last glacial period (18000–15000 years ago). Dawn of human stone-age cultures, with increasing technical complexity relative to previous ice age cultures, such as engravings and clay statues (e.g. Venus of Lespugue), particularly in the Mediterranean and Europe. Lake Toba supervolcano erupts 75000 years before present, causing a volcanic winter that pushes humanity to the brink of extinction. Pleistocene ends with Oldest Dryas, Older Dryas/Allerød and Younger Dryas climate events, with Younger Dryas forming the boundary with the Holocene. | 0.129 | ||||
Middle (formerly Ionian) | 0.774 | ||||||
Calabrian | 1.8* | ||||||
Gelasian | 2.58* | ||||||
Neogene | Pliocene | Piacenzian/Blancan | Intensification of present Icehouse conditions, present (Quaternary) ice age begins roughly 2.58 Ma; cool and dry climate. Australopithecines, many of the existing genera of mammals, and recent mollusks appear. Homo habilis appears. | 3.6* | |||
Zanclean | 5.333* | ||||||
Miocene | Messinian | Moderate Icehouse climate, punctuated by ice ages; Orogeny in Northern Hemisphere. Modern mammal and bird families become recognizable. Horses and mastodons diverse. Grasses become ubiquitous. First apes appear (for reference see the article: "Sahelanthropus tchadensis"). Kaikoura Orogeny forms Southern Alps in New Zealand, continues today. Orogeny of the Alps in Europe slows, but continues to this day. Carpathian orogeny forms Carpathian Mountains in Central and Eastern Europe. Hellenic orogeny in Greece and Aegean Sea slows, but continues to this day. Middle Miocene Disruption occurs. Widespread forests slowly draw in massive amounts of CO2, gradually lowering the level of atmospheric CO2 from 650 ppmv down to around 100 ppmv.[26][27] | 7.246* | ||||
Tortonian | 11.63* | ||||||
Serravallian | 13.82* | ||||||
Langhian | 15.98 | ||||||
Burdigalian | 20.44 | ||||||
Aquitanian | 23.03* | ||||||
Paleogene | Oligocene | Chattian | Warm but cooling climate, moving towards Icehouse; Rapid evolution and diversification of fauna, especially mammals. Major evolution and dispersal of modern types of flowering plants | 27.82 | |||
Rupelian | 33.9* | ||||||
Eocene | Priabonian | Moderate, cooling climate. Archaic mammals (e.g. Creodonts, Condylarths, Uintatheres, etc.) flourish and continue to develop during the epoch. Appearance of several "modern" mammal families. Primitive whales diversify. First grasses. Reglaciation of Antarctica and formation of its ice cap; Azolla event triggers ice age, and the Icehouse Earth climate that would follow it to this day, from the settlement and decay of seafloor algae drawing in massive amounts of atmospheric carbon dioxide,[26][27] lowering it from 3800 ppmv down to 650 ppmv. End of Laramide and Sevier Orogenies of the Rocky Mountains in North America. Orogeny of the Alps in Europe begins. Hellenic Orogeny begins in Greece and Aegean Sea. | 37.71 | ||||
Bartonian | 41.2 | ||||||
Lutetian | 47.8* | ||||||
Ypresian | 56* | ||||||
Paleocene | Thanetian | Climate tropical. Modern plants appear; Mammals diversify into a number of primitive lineages following the extinction of the dinosaurs. First large mammals (up to bear or small hippo size). Alpine orogeny in Europe and Asia begins. Indian Subcontinent collides with Asia 55 Ma, Himalayan Orogeny starts between 52 and 48 Ma. | 59.2* | ||||
Selandian | 61.6* | ||||||
Danian | 66* | ||||||
Mesozoic | Cretaceous | Late | Maastrichtian | Flowering plants proliferate, along with new types of insects. More modern teleost fish begin to appear. Ammonoidea, belemnites, rudist bivalves, echinoids and sponges all common. Many new types of dinosaurs (e.g. Tyrannosaurs, Titanosaurs, duck bills, and horned dinosaurs) evolve on land, as do Eusuchia (modern crocodilians); and mosasaurs and modern sharks appear in the sea. Primitive birds gradually replace pterosaurs. Monotremes, marsupials and placental mammals appear. Break up of Gondwana. Beginning of Laramide and Sevier Orogenies of the Rocky Mountains. atmospheric CO2 close to present-day levels. | 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* | ||||||
Early | Albian | ~113 | |||||
Aptian | ~121.4 | ||||||
Barremian | ~125.77 | ||||||
Hauterivian | ~132.6 | ||||||
Valanginian | ~139.8 | ||||||
Berriasian | ~145 | ||||||
Jurassic | Late | Tithonian | Gymnosperms (especially conifers, Bennettitales and cycads) and ferns common. Many types of dinosaurs, such as sauropods, carnosaurs, and stegosaurs. Mammals common but small. First birds and lizards. Ichthyosaurs and plesiosaurs diverse. Bivalves, Ammonites and belemnites abundant. Sea urchins very common, along with crinoids, starfish, sponges, and terebratulid and rhynchonellid brachiopods. Breakup of Pangaea into Gondwana and Laurasia. Nevadan orogeny in North America. Rantigata and Cimmerian Orogenies taper off. Atmospheric CO2 levels 4–5 times the present day levels (1200–1500 ppmv, compared to today's 385 ppmv[26][27]). | 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* | ||||||
Early | Toarcian | 184.2 ± 0.7* | |||||
Pliensbachian | 192.9 ± 1.0* | ||||||
Sinemurian | 199.5 ± 0.3* | ||||||
Hettangian | 201.4 ± 0.2* | ||||||
Triassic | Late | Rhaetian | Archosaurs dominant on land as dinosaurs, in the oceans as Ichthyosaurs and nothosaurs, and in the air as pterosaurs. Cynodonts become smaller and more mammal-like, while first mammals and crocodilia appear. Dicroidiumflora common on land. Many large aquatic temnospondyl amphibians. Ceratitic ammonoids extremely common. Modern corals and teleost fish appear, as do many modern insect clades. 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) | ~208.5 | |||
Norian | ~227 | ||||||
Carnian | ~237* | ||||||
Middle | Ladinian | ~242* | |||||
Anisian | 247.2 | ||||||
Early | Olenekian | 251.2 | |||||
Induan | 251.902 ± 0.06* | ||||||
Paleozoic | Permian | Lopingian | Changhsingian | Landmasses unite into supercontinent Pangaea, creating the Appalachians. End of Permo-Carboniferous glaciation. Synapsid reptiles (pelycosaurs and therapsids) become plentiful, while parareptiles and temnospondyl amphibians remain common. In the mid-Permian, coal-age flora are replaced by cone-bearing gymnosperms (the first true seed plants) and by the first true mosses. Beetles and flies evolve. Marine life flourishes in warm shallow reefs; productid and spiriferid brachiopods, bivalves, forams, and ammonoids all abundant. Permian-Triassic extinction event occurs 251 Ma: 95% of life on Earth becomes extinct, including all trilobites, graptolites, and blastoids. 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 ± 0.4* | ||||||
Guadalupian | Capitanian | 264.28 ± 0.4* | |||||
Wordian/Kazanian | 266.9 ± 0.5* | ||||||
Roadian/Ufimian | 273.01 ± 0.5* | ||||||
Cisuralian | Kungurian | 283.5 ± 0.6 | |||||
Artinskian | 290.1 ± 0.26 | ||||||
Sakmarian | 293.52 ± 0.18 | ||||||
Asselian | 298.9 ± 0.15* | ||||||
Carbon- iferous[29] |
Pennsylvanian | Gzhelian | Winged insects radiate suddenly; some (esp. Protodonata and Palaeodictyoptera) are quite large. Amphibians common and diverse. First reptiles and coal forests (scale trees, ferns, club trees, giant horsetails, Cordaites, etc.). Highest-ever atmospheric oxygen levels. Goniatites, brachiopods, bryozoa, bivalves, and corals plentiful in the seas and oceans. Testate forams proliferate. Uralian orogeny in Europe and Asia. Variscan orogeny occurs towards middle and late Mississippian Periods. | 303.7 ± 0.1 | |||
Kasimovian | 307 ± 0.1 | ||||||
Moscovian | 315.2 ± 0.2 | ||||||
Bashkirian | 323.2 ± 0.4* | ||||||
Mississippian | Serpukhovian | Large primitive trees, first land vertebrates, and amphibious sea-scorpions live amid coal-forming coastal swamps. Lobe-finned rhizodonts are dominant big fresh-water predators. In the oceans, early sharks are common and quite diverse; echinoderms (especially crinoids and blastoids) abundant. Corals, bryozoa, goniatites and brachiopods (Productida, Spiriferida, etc.) very common, but trilobites and nautiloids decline. Glaciation in East Gondwana. Tuhua Orogeny in New Zealand tapers off. | 330.9 ± 0.2 | ||||
Viséan | 346.7 ± 0.4* | ||||||
Tournaisian | 358.9 ± 0.4* | ||||||
Devonian | Late | Famennian | First clubmosses, horsetails and ferns appear, as do the first seed-bearing plants (progymnosperms), first trees (the progymnosperm Archaeopteris), and first (wingless) insects. Strophomenid and atrypid brachiopods, rugose and tabulate corals, and crinoids are all abundant in the oceans. Goniatite ammonoids are plentiful, while squid-like coleoids arise. Trilobites and armoured agnaths decline, while jawed fishes (placoderms, lobe-finned and ray-finned fish, and early sharks) rule the seas. First amphibians still aquatic. "Old Red Continent" of Euramerica. Beginning of Acadian Orogeny for Anti-Atlas Mountains of North Africa, and Appalachian Mountains of North America, also the Antler, Variscan, and Tuhua Orogeny in New Zealand. | 372.2 ± 1.6* | |||
Frasnian | 382.7 ± 1.6* | ||||||
Middle | Givetian | 387.7 ± 0.8* | |||||
Eifelian | 393.3 ± 1.2* | ||||||
Early | Emsian | 407.6 ± 2.6* | |||||
Pragian | 410.8 ± 2.8* | ||||||
Lochkovian | 419.2 ± 3.2* | ||||||
Silurian | Pridoli | First Vascular plants (the rhyniophytes and their relatives), first millipedes and arthropleurids on land. First jawed fishes, as well as many armoured jawless fish, populate the seas. Sea-scorpions reach large size. Tabulate and rugose corals, brachiopods (Pentamerida, Rhynchonellida, etc.), and crinoids all abundant. Trilobites and mollusks diverse; graptolites not as varied. Beginning of Caledonian Orogeny for hills in England, Ireland, Wales, Scotland, and the Scandinavian Mountains. Also continued into Devonian period as the Acadian Orogeny, above. Taconic Orogeny tapers off. Lachlan Orogeny on Australian continent tapers off. | 423 ± 2.3* | ||||
Ludlow/Cayugan | Ludfordian | 425.6 ± 0.9* | |||||
Gorstian | 427.4 ± 0.5* | ||||||
Wenlock | Homerian/ Lockportian |
430.5 ± 0.7* | |||||
Sheinwoodian/ Tonawandan |
433.4 ± 0.8* | ||||||
Llandovery/ Alexandrian |
Telychian/ Ontarian |
438.5 ± 1.1* | |||||
Aeronian | 440.8 ± 1.2* | ||||||
Rhuddanian | 443.8 ± 1.5* | ||||||
Ordovician | Late | Hirnantian | Invertebrates diversify into many new types (e.g., long straight-shelled cephalopods). Early corals, articulate brachiopods (Orthida, Strophomenida, etc.), bivalves, nautiloids, trilobites, ostracods, bryozoa, many types of echinoderms (crinoids, cystoids, starfish, etc.), branched graptolites, and other taxa all common. Conodonts (early planktonic vertebrates) appear. First green plants and fungi on land. Ice age at end of period. | 445.2 ± 1.4* | |||
Katian | 453 ± 0.7* | ||||||
Sandbian | 458.4 ± 0.9* | ||||||
Middle | Darriwilian | 467.3 ± 1.1* | |||||
Dapingian | 470 ± 1.4* | ||||||
Early | Floian (formerly Arenig) |
477.7 ± 1.4* | |||||
Tremadocian | 485.4 ± 1.9* | ||||||
Cambrian | Furongian | Stage 10 | Major diversification of life in the Cambrian Explosion. Numerous fossils; most modern animal phyla appear. First chordates appear, along with a number of extinct, problematic phyla. Reef-building Archaeocyatha abundant; then vanish. Trilobites, priapulid worms, sponges, inarticulate brachiopods (unhinged lampshells), and many other animals numerous. Anomalocarids are giant predators, while many Ediacaran fauna die out. Prokaryotes, protists (e.g., forams), fungi and algae continue to present day. Gondwana emerges. Petermann Orogeny on the Australian continent tapers off (550–535 Ma). Ross Orogeny in Antarctica. Adelaide Geosyncline (Delamerian Orogeny), majority of orogenic activity from 514–500 Ma. Lachlan Orogeny on Australian continent, c. 540–440 Ma. Atmospheric CO2 content roughly 20–35 times present-day (Holocene) levels (6000 ppmv compared to today's 385 ppmv)[26][27] | ~489.5 | |||
Jiangshanian | ~494* | ||||||
Paibian | ~497* | ||||||
Series 3 | Guzhangian | ~500.5* | |||||
Drumian | ~504.5* | ||||||
Stage 5 | ~509 | ||||||
Series 2 | Stage 4 | ~514 | |||||
Stage 3 | ~521 | ||||||
Terreneuvian | Stage 2 | ~529 | |||||
Fortunian | 538.8 ± 1.0* | ||||||
Precambrian[30] | Proterozoic[31] | Neoproterozoic[31] | Ediacaran | Good fossils of the first multi-celled animals. Ediacaran biota flourish worldwide in seas. Simple trace fossils of possible worm-like Trichophycus, etc. First sponges and trilobitomorphs. Enigmatic forms include many soft-jellied creatures shaped like bags, disks, or quilts (likeDickinsonia). Taconic Orogeny in North America. Aravalli Range orogeny in Indian Subcontinent. Beginning of Petermann Orogeny on Australian continent. Beardmore Orogeny in Antarctica, 633–620 Ma. | ~635* | ||
Cryogenian | Possible "Snowball Earth" period. Fossils still rare. Rodinia landmass begins to break up. Late Ruker / Nimrod Orogeny in Antarctica tapers of<bef. | 720[32] | |||||
Tonian | Rodinia supercontinent persists. Trace fossils of simple multi-celled eukaryotes. First radiation of dinoflagellate-like acritarchs. Grenville Orogeny tapers off in North America. Pan-African orogeny in Africa. Lake Ruker / Nimrod Orogeny in Antarctica, 1000 ± 150 Ma. Edmundian Orogeny (c. 920 – 850 Ma), Gascoyne Complex, Western Australia. Adelaide Geosyncline laid down on Australian continent, beginning of Adelaide Geosyncline (Delamerian Orogeny) in that continent. | 1000[32] | |||||
Mesoproterozoic[31] | Stenian | Narrow highly metamorphic belts due to orogeny as Rodinia forms. Late Ruker / Nimrod Orogeny in Antarctica possibly begins. Musgrave Orogeny (c. 1080 Ma), Musgrave Block, Central Australia. | 1200[32] | ||||
Ectasian | Platform covers continue to expand. Green algae colonies in the seas. Grenville Orogeny in North America. | 1400[32] | |||||
Calymmian | Platform covers expand. Barramundi Orogeny, McArthur Basin, Northern Australia, and Isan Orogeny, c.1600 Ma, Mount Isa Block, Queensland | 1600[32] | |||||
Paleoproterozoic[31] | Statherian | First complex single-celled life: protists with nuclei. Columbia is the primordial supercontinent. Kimban Orogeny in Australian continent ends. Yapungku Orogeny on Yilgarn craton, in Western Australia. Mangaroon Orogeny, 1680–1620 Ma, on the Gascoyne Complex in Western Australia. Kararan Orogeny (1650– Ma), Gawler Craton, South Australia. | 1800[32] | ||||
Orosirian | The atmosphere becomes oxygenic. Vredefort and Sudbury Basin asteroid impacts. Much orogeny. Penokean and Trans-Hudsonian Orogenies in North America. Early Ruker Orogeny in Antarctica, 2000–1700 Ma. Glenburgh Orogeny, Glenburgh Terrane, Australian continent c. 2005–1920 Ma. Kimban Orogeny, Gawler craton in Australian continent begins. | 2050[32] | |||||
Rhyacian | Bushveld Igneous Complex forms. Huronian glaciation. | 2300[32] | |||||
Siderian | Oxygen catastrophe: banded iron formations forms. Sleaford Orogeny on Australian continent, Gawler Craton 2440–2420 Ma. | 2500[32] | |||||
Archean[31] | Neoarchean[31] | Stabilization of most modern cratons; possible mantle overturn event. Insell Orogeny, 2650 ± 150 Ma. Abitibi greenstone belt in present-day Ontario and Quebec begins to form, stabilizes by 2600 Ma. | 2800[32] | ||||
Mesoarchean[31] | First stromatolites (probably colonial cyanobacteria). Oldest macrofossils. Humboldt Orogeny in Antarctica. Blake River Megacaldera Complex begins to form in present-day Ontario and Quebec, ends by roughly 2696 Ma. | 3200[32] | |||||
Paleoarchean[31] | First known oxygen-producing bacteria. Oldest definitive microfossils. Oldest cratons on Earth (such as the Canadian Shield and the Pilbara Craton) may have formed during this period.[33] Rayner Orogeny in Antarctica. | 3600[32] | |||||
Eoarchean[31] | Simple single-celled life (probably bacteria and archaea). Oldest probable microfossils. | 4031 | |||||
Hadean[31][34] | Early Imbrian[31][35] | Indirect photosynthetic evidence (e.g., kerogen) of primordial life. This era overlaps the end of the Late Heavy Bombardment of the Inner Solar System. | ~4100 | ||||
Nectarian[31][35] | This unit gets its name from the lunar geologic timescale when the Nectaris Basin and other greater lunar basins form by big impact events. | ~4300 | |||||
Basin Groups[31][35] | Oldest known rock (4030 Ma).[36] The first life forms and self-replicating RNA molecules evolve around 4000 Ma, after the Late Heavy Bombardment ends on Earth. Napier Orogeny in Antarctica, 4000 ± 200 Ma. | ~4500 | |||||
Cryptic[31][35] | Oldest known mineral (Zircon, 4404 ± 8 Ma).[37] Formation of Moon (4533 Ma), probably from giant impact. Formation of Earth (4567.17 to 4570 Ma) | ~4567 |
Proposed Precambrian timeline
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.[38]
- Hadean Eon – 4600–4030 MYA
- Chaotian Era – 4600–4404 MYA – the name alluding both to the mythological Chaos and the chaotic phase of planet formation[38][39][40]
- Jack Hillsian or Zirconian Era – 4404–4030 MYA – both names allude to the Jack Hills Greenstone Belt which provided the oldest mineral grains on Earth, zircons[38][39]
- Archean Eon – 4030–2420 MYA
- Paleoarchean Era – 4030–3490 MYA
- Acastan Period – 4030–3810 MYA – named after the Acasta Gneiss[38][39]
- Isuan Period – 3810–3490 MYA – named after the Isua Greenstone Belt[38]
- Mesoarchean Era – 3490–2780 MYA
- Vaalbaran Period – 3490–3020 MYA – a portmanteau based on the names of the Kapvaal (Southern Africa) and Pilbara (Western Australia) cratons[38]
- Pongolan Period – 3020–2780 MYA – named after the Pongola Supergroup[38]
- Neoarchean Era – 2780–2420 MYA
- Methanian Period – 2780–2630 MYA – named for the inferred predominance of methanotrophic prokaryotes[38]
- Siderian Period – 2630–2420 MYA – named for the voluminous banded iron formations formed within its duration[38]
- Paleoarchean Era – 4030–3490 MYA
- Proterozoic Eon – 2420–541 MYA
- Paleoproterozoic Era – 2420–1780 MYA
- Oxygenian Period – 2420–2250 MYA – named for displaying the first evidence for a global oxidizing atmosphere[38]
- Jatulian or Eukaryian Period – 2250–2060 MYA – names are respectively for the Lomagundi–Jatuli δ13C isotopic excursion event spanning its duration, and for the first fossil appearance of eukaryotes[38]
- Columbian Period – 2060–1780 MYA – named after the supercontinent Columbia[38]
- Mesoproterozoic Era – 1780–850 MYA
- Neoproterozoic Era – 850–541 MYA
- Cryogenian Period – 850–635 MYA – named for the occurrence of several glaciations[38]
- Ediacaran Period – 635–541 MYA
- Paleoproterozoic Era – 2420–1780 MYA
Shown to scale:
![](http://upload.wikimedia.org/wikipedia/en/timeline/ht3wcwgtcc6k5f0y8wor1b84jmdjuw3.png)
Compare with the current official one:
![](http://upload.wikimedia.org/wikipedia/en/timeline/dz9wbyony43bfavvbzawi7xahswzk92.png)
See also
- Age of the Earth
- Anthropocene
- Bubnoff unit
- Deep time
- Evolutionary history of life
- Geological history of Earth
- Geology of Mars/areology
- Geon
- Graphical timeline of the universe
- History of the Earth
- History of geology
- History of paleontology
- List of fossil sites
- Logarithmic timeline
- Lunar 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 and references
- ^ a b "International Stratigraphic Chart". International Commission on Stratigraphy.
- ^ Cohen, K.M.; Finney, S.; Gibbard, P.L. (2015), International Chronostratigraphic Chart (PDF), International Commission on Stratigraphy.
- ^ a b International Commission on Stratigraphy. "Chronostratigraphic Units." International Stratigraphic Guide. Accessed 14 December 2009. stratigraphy.org
- ^ Statutes of the International Commission on Stratigraphy, retrieved 26 November 2009
- ^ Correlating Earth's History, Paul R. Janke
- ^ Rudwick, M. J. S. (1985). The Meaning of Fossils: Episodes in the History of Palaeontology. University of Chicago Press. p. 24. ISBN 0-226-73103-0.
- ^ Fischer, Alfred G.; Garrison, Robert E. (2009). "The role of the Mediterranean region in the development of sedimentary geology: A historical overview". Sedimentology. 56: 3. Bibcode:2009Sedim..56....3F. doi:10.1111/j.1365-3091.2008.01009.x.
- ^ Quoted in The contribution of Ibn Sina (Avicenna) to the development of the Earth Sciences, among other sources
- ^ Sivin, Nathan (1995). Science in Ancient China: Researches and Reflections. Brookfield, Vermont: Ashgate Publishing Variorum series. III, 23–24.
{{cite book}}
: Unknown parameter|nopp=
ignored (|no-pp=
suggested) (help) - ^ John McPhee, Basin and Range, New York:Farrar, Straus and Giroux, 1981, pp. 95–100.
- ^ John McPhee, Basin and Range, pp. 113–114.
- ^ Great Soviet Encyclopedia (in Russian) (3rd ed.). Moscow: Sovetskaya Enciklopediya. 1974. vol. 16, p. 50.
{{cite encyclopedia}}
: Unknown parameter|nopp=
ignored (|no-pp=
suggested) (help) - ^ Rudwick, Martin Worlds Before Adam: The Reconstruction of Geohistory in the Age of Reform (2008) pp. 539–545
- ^ Geologic Time Scale
- ^ How the discovery of geologic time changed our view of the world, Bristol University
- ^ Felix M. Gradstein, James G. Ogg, Alan G. Smith (Editors); A Geologic Time Scale 2004, Cambridge University Press, 2005, (ISBN 0-521-78673-8)
- ^ Cox, Simon J. D.; Richard, Stephen M. (2005). "A formal model for the geologic time scale and global stratotype section and point, compatible with geospatial information transfer standards". Geosphere. 1 (3). The Geological Society of America: 119–137. doi:10.1130/GES00022.1. Retrieved 31 December 2012.
- ^ "Geologic Timescale Elements in the International Chronostratigraphic Chart". Retrieved 3 August 2014.
- ^ Simon J. D. Cox. "SPARQL endpoint for CGI timescale service". Retrieved 3 August 2014.
- ^ Simon J. D. Cox, Stephen M. Richard. "A geologic timescale ontology and service". Retrieved 3 August 2014.
- ^ Paleontologists often refer to faunal stages rather than geologic (geological) periods. The stage nomenclature is quite complex. For a time-ordered list of faunal stages, see "The Paleobiology Database". Retrieved 19 March 2006.
- ^ a b 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 2015 time scale except the Hadean eon. Where errors are not quoted, errors are less than the precision of the age given.
* indicates boundaries where a Global Boundary Stratotype Section and Point has been internationally agreed upon. - ^ References to the "Post-Cambrian Supereon" are not universally accepted, and therefore must be considered unofficial.
- ^ 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 recognizes a slightly extended Quaternary as well as the Paleogene and a truncated Neogene, the Tertiary having been demoted to informal status.
- ^ "NASA Scientists React to 400 ppm Carbon Milestone". Retrieved 2014-01-15 [1]
- ^ a b c d e f Royer, Dana L. (2006). "CO2-forced climate thresholds during the Phanerozoic" (PDF). Geochimica et Cosmochimica Acta. 70 (23): 5665–75. Bibcode:2006GeCoA..70.5665R. doi:10.1016/j.gca.2005.11.031.
- ^ a b c d e f 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 start time for the Holocene epoch is here given as 11,700 years ago. For further discussion of the dating of this epoch, see Holocene.
- ^ In North America, the Carboniferous is subdivided into Mississippian and Pennsylvanian Periods.
- ^ The Precambrian is also known as Cryptozoic.
- ^ a b c d e f g h i j k l m n The Proterozoic, Archean and Hadean are often collectively referred to as the Precambrian Time or sometimes, also the Cryptozoic.
- ^ a b c d e f g h i j k l Defined by absolute age (Global Standard Stratigraphic Age).
- ^ The age of the oldest measurable craton, or continental crust, is dated to 3600–3800 Ma
- ^ Though commonly used, the Hadean is not a formal eon 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 and Basin Groups (which are subdivisions of the Pre-Nectarian era), Nectarian, and Early Imbrian units.
- ^ a b c d 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.
- ^ Bowring, Samuel A.; Williams, Ian S. (1999). "Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada". Contributions to Mineralogy and Petrology. 134 (1): 3. Bibcode:1999CoMP..134....3B. doi:10.1007/s004100050465. The oldest rock on Earth is the Acasta Gneiss, and it dates to 4.03 Ga, located in the Northwest Territories of Canada.
- ^ Geology.wisc.edu
- ^ a b c d e f g h i j k l m n Van Kranendonk, Martin J. (2012). "16: A Chronostratigraphic Division of the Precambrian: Possibilities and Challenges". In Felix M. Gradstein, James G. Ogg, Mark D. Schmitz and Gabi M. Ogg (ed.). The geologic time scale 2012 (1st ed.). Amsterdam: Elsevier. pp. 359–365. ISBN 978-0-44-459425-9.
{{cite book}}
: CS1 maint: multiple names: editors list (link) - ^ a b c Goldblatt, C.; K. J. Zahnle; N. H. Sleep; E. G. Nisbet (2010). "The Eons of Chaos and Hades" (PDF). Solid Earth. 1. Copernicus Publications on behalf of the European Geosciences Union: 1–3.
- ^ Chambers, John E. (July 2004). "Planetary accretion in the inner Solar System" (PDF). Earth and Planetary Science Letters. 223 (3–4): 241–252. doi:10.1016/j.epsl.2004.04.031.
Further reading
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/df/Wikibooks-logo-en-noslogan.svg/40px-Wikibooks-logo-en-noslogan.svg.png)
- 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" (PDF). Stratigraphy. 6 (2): 100–105. Retrieved 18 November 2011.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Gradstein, F. M.; Ogg, J. G. (2004). A Geologic Time scale 2004 – Why, How and Where Next! (PDF). Retrieved 18 November 2011.
- Gradstein, Felix M., Ogg, James G. & Smith, Alan G. (2004). A Geologic Time Scale 2004. New York; Cambridge, UK: Cambridge University Press. ISBN 0-521-78142-6. Retrieved 18 November 2011 Paperback ISBN 0-521-78673-8
{{cite book}}
: CS1 maint: multiple names: authors list (link) CS1 maint: postscript (link) - 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" (PDF). Episodes. 27 (2): 83–100. Retrieved 18 November 2011.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - 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. Retrieved 18 November 2011.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - 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.
External links
- NASA: Geologic Time
- GSA: Geologic Time Scale
- British Geological Survey: Geological Timechart
- GeoWhen Database
- International Commission on Stratigraphy Time Scale
- Chronos.org
- National Museum of Natural History – Geologic Time
- SeeGrid: Geological Time Systems 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