Kimmeridgian

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Kimmeridgian
157.3 – 152.1 ± 0.9 Ma
Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionNot formally defined
Lower boundary definition candidatesFAD of the Ammonite Pictonia baylei
Lower boundary GSSP candidate section(s)Flodigarry, Skye, Scotland, UK
Upper boundary definitionNot formally defined
Upper boundary definition candidates
Upper boundary GSSP candidate section(s)

In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxfordian and precedes the Tithonian.[2]

Stratigraphic definition[edit]

The Kimmeridgian stage takes its name from the village of Kimmeridge on the Dorset coast, England. The name was introduced into the literature by French geologist Alcide d'Orbigny in 1842.[3] The Kimmeridge Clay Formation takes its name from the same type location. It is the source for about 95% of the petroleum in the North Sea.[citation needed]

Historically, the term Kimmeridgian has been used in two different ways. The base of the interval is the same but the top was defined by British stratigraphers as the base of the Portlandian (sensu anglico) whereas in France the top was defined as the base of the Tithonian (sensu gallico). The differences have not yet been fully resolved; As of 2004 Tithonian is the uppermost stage of the Jurassic in the timescale of the ICS.[4]

The base of the Kimmeridgian is at the first appearance of ammonite species Pictonia baylei in the stratigraphic column.[5] A global reference profile for the base (the GSSP of the Kimmeridgian stage) had in 2009 not yet been assigned.[citation needed] The top of the Kimmeridgian (the base of the Tithonian) is at the first appearance of ammonite species Hybonoticeras hybonotum. It also coincides with the top of magnetic anomaly M22An.[5]

Subdivision[edit]

The Kimmeridgian is sometimes[weasel words] subdivided into Upper and Lower substages.[citation needed] In the Tethys domain, the Kimmeridgian contains seven ammonite biozones:[citation needed]

Palaeontology[edit]

Amphibians[edit]

Amphibians of the Kimmeridgian
Taxa Presence Location Description Images
Morrison Formation, Utah An extinct genus of cryptobranchoid salamander.

†Ankylosaurs[edit]

Ankylosaurs of the Kimmeridgian
Taxa Presence Location Description Images
Morrison Formation, Wyoming, USA The smallest and the earliest well-known ankylosaur. Its skull measures only 29 cm in length, and its total body length is an estimated three to four meters.
Gargoyleosaurus skeleton from Wyoming
  • Mymoorapelta maysi
Morrison Formation, Colorado, USA A poorly known early ankylosaurian.

Birds[edit]

Birds of the Kimmeridgian
Taxa Presence Location Description Images
  • Archaeopteryx lithographica
Life restoration of Archaeopteryx lithographica

†Ornithopods[edit]

Ornithopoda of the Kimmeridgian
Taxa Presence Location Description Images
Kimmeridgian to Tithonian Wyoming, USA Camptosaurus could be more than 7.9 meters (26 feet) long, and 2.0 meters (6.6 feet) tall at the hips. It had heavy bodies but, as well as walking on four legs (quadrupedal), they could rear up to walk on two legs (bipedal). This genus is probably closely related to the ancestor of the later iguanodontid and hadrosaurid dinosaurs. It probably ate cycads with its parrot-like beak.
Camptosaurus
Othnielosaurus

†Plesiosaurs[edit]

Plesiosaurs of the Kimmeridgian
Taxa Presence Location Description Images
Liopleurodon
Bajocian-Tithonian

†Sauropods[edit]

Sauropods of the Kimmeridgian
Taxa Presence Location Description Images
Europasaurus holgeri
  • Europasaurus holgeri
Kimmeridge Clay Formation, England
Morrison Formation, Colorado
Kimmeridge Clay Formation, Dorset, England The genus is preoccupied by a name Edward Drinker Cope coined in 1869.

†Stegosaurs[edit]

Stegosaurs of the Kimmeridgian
Taxa Presence Location Description Images
England and France A large stegosaurid
Dacentrurus
Stegosaurus
Upper Shaximiao Formation, Sichuan, China Had relatively small dorsal plates and greatly enlarged shoulder spines, twice the length of the shoulder blades. Estimated to have been about 4 metres long.
Lourinhã Formation, Portugal Closer to Dacentrurus than Stegosaurus.
*Hesperosaurus Morrison Formation, Wyoming, USA Had alternating plates on its back and four spikes on its tail. Appears more closely related to Dacentrurus than Stegosaurus.
Tanzania A 4 meter long stegosaurian with spikes on its flanks. The length of the thigh bone compared with the rest of the leg indicates that Kentrosaurus was a slow and inactive dinosaur.
Loe-ein Formation, Tibet, China The fragmentary condition of the only known skeleton places doubt on the validity of this genus
Kimmeridgian to Early Tithonian Morrison Formation, Colorado, Utah, Wyoming, USA Averaging around 9 metres (30 feet) long and 4 metres (13 feet) tall, the quadrupedal Stegosaurus is one of the most easily identifiable dinosaurs, due to the distinctive double row of kite-shaped plates rising vertically along its arched back and the two pairs of long spikes extending horizontally near the end of its tail.

†Thalattosuchians[edit]

Thalattosuchians of the Kimmeridgian
Taxa Presence Location Description Images
C. suevicus
Germany A relatively small metriorhynchid genus.
Dakosaurus, a marine crocodilian
Metriorhynchus, a marine crocodilian
D. maximus
Germany A large metriorhynchid. The type species of the genus, Dakosaurus maximus, is known from Western Europe (England, France, Switzerland and Germany) of the Late Jurassic (Late Kimmeridgian-Early Tithonian).
  1. M. hugii
  2. M. mosae
  3. M. nowackianus
  4. M. buffetauti
  • M. hugii: Western Europe
  • M. mosae: France
  • M. nowackianus: Harrar, Ethiopia
  • M. buffetauti: Germany
Machimosaurus hugii was the largest named teleosaurid and thalattosuchian up to its time, with an estimated length of approximately 7.2 metres
  1. M. nuyivijanan
Sabinal Formation, Tlaxiaco Basin, Oaxaca, Mexico A metriorhynchid. It is the most basal genus of the Rhacheosaurini Tribe.
  1. M. geoffroyii
  2. M. hastifer
England, France and Switzerland An opportunistic carnivore that fed on fish, belemnites and other marine animals and possible carrion. Metriorhynchus grew to an average adult length of 3 meters (9.8 feet).
  1. T. carpenteri
  2. T. coryphaeus
  3. T. mexicanus
Kimmeridge Clay Formation, Wiltshire, England; Oaxaca, Mexico

†Theropods (non-avian)[edit]

Non-avian theropods of the Kimmeridgian
Taxa Presence Location Description Images
Allosaurus
Ceratosaurus
Coelurus
Elaphrosaurus
Lourinhanosaurus
Marshosaurus
Ornitholestes
Tanycolagreus
Torvosaurus
  • Aviatyrannis jurassica
Guimarota Mine, Portugal Small 5 kg tyrannosauroid. Aviatyrannis along with Stokesosaurus represents the oldest known tyrannosauroids.
  • Coelurus fragilis
Morrison Formation, Wyoming Small theropod about 2 metres in length
  • Elaphrosaurus bambergi
Tendaguru Beds, Tanzania Probably a ceratosaur about 6 meters long
  • Fosterovenator churei
Morrison Formation, Wyoming Probably a ceratosaur.
Lourinhã Formation, Portugal A genus of medium sized carnivorous theropod dinosaurs. A basal tetanuran, might be an allosauroid, megalosauroid or a coelurosaur.
  • Marshosaurus bicentesimus
Cleveland-Lloyd Quarry, Brushy Basin Member, Morrison Formation, Utah and possibly Colorado
  • Ornitholestes hermanni
Bone Cabin Quarry, Morrison Formation, Wyoming Ornitholestes hermanni is a species of basal coelurosaurian theropod.
  • Saurophaganax maximus
Morrison Formation, Oklahoma Possibly a species of Allosaurus but larger and much rarer than Allosaurus' type species. Estimated from 10.5 to 13 meters in length and from 3 to 4.5 metric tons in weight it's potentially the largest terrestrial predator of the Jurassic.
  • Tanycolagreus topwilsoni
Morrison Formation, Wyoming Tanycolagreus is a genus of basal coelurosaurian theropod.
  • Torvosaurus tanneri
  • Torvosaurus gurneyi
Torvosaurus was a very large megalosaurid predator, with an estimated maximum body length of 10 m (33 ft) and mass of 3.6–4.5 tonnes (4–5 short tons) for both its species, making Torvosaurus among the largest land carnivores of the Jurassic. Thomas Holtz estimated it at 12 meters (39 feet). Claims have been made indicating even larger sizes.

Nautiloids[edit]

Nautiloids of the Kimmeridgian
Taxa Presence Location Description Images
An illustration of a variety of fossil nautiloids

†Ammonites[edit]

Ammonites of the Kimmeridgian
Taxa Presence Location Description Images
Lithacosphinctes achilles

†Belemnites[edit]

Belemnites of the Kimmeridgian
Taxa Presence Location Description Images
Small belemnite fossils

Palaeontological sites[edit]

References[edit]

Notes[edit]

  1. ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy.
  2. ^ "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 23 December 2020.
  3. ^ Gradstein, F.M.; Ogg, J.G.; Schmitz, M.D.; Ogg, G.M. (editors) (2012). The Geologic Timescale 2012 (volume 1). Elsevier. p. 745. ISBN 978-0-44-459390-0.CS1 maint: uses authors parameter (link)
  4. ^ INTERNATIONAL SUBCOMMISSION ON JURASSIC STRATIGRAPHY, Newsletter 31, Edited by Nicol Morton and Paul Bown, August 2004
  5. ^ a b "Global Boundary Stratotype Section and Point (GSSP) of the International Commission on Stratigraphy". GSSP Table - All Periods. International Commission on Stratigraphy. Retrieved 5 January 2018.
  6. ^ Mateus, Octávio; Hendrickx, Christophe (5 March 2014). "Torvosaurus gurneyi n. sp., the Largest Terrestrial Predator from Europe, and a Proposed Terminology of the Maxilla Anatomy in Nonavian Theropods". PLOS ONE. 9 (3): e88905. doi:10.1371/journal.pone.0088905. ISSN 1932-6203. PMC 3943790. PMID 24598585.

Literature[edit]

  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
  • Thurmann, J.; 1832: Sur Les Soulèvemens Jurassiques Du Porrentruy: Description Géognostique de la Série Jurassique et Théorie Orographique du Soulèvement, Mémoires de la Société d'histoire naturelle de Strasbourg 1: pp 1–84, F. G. Levrault, Paris.(in French)

External links[edit]