Oxfordian (stage)

The Oxfordian is, in the ICS' geologic timescale, the earliest age of the Late Jurassic epoch, or the lowest stage of the Upper Jurassic series. It spans the time between 163.5 ± 4 Ma and 157.3 ± 4 Ma (million years ago). The Oxfordian is preceded by the Callovian and is followed by the Kimmeridgian.[2]

System/
Period
Series/
Epoch
Stage/
Age
Age (Ma)
Cretaceous Lower/
Early
Berriasian younger
Jurassic Upper/
Late
Tithonian ~145.0 152.1
Kimmeridgian 152.1 157.3
Oxfordian 157.3 163.5
Middle Callovian 163.5 166.1
Bathonian 166.1 168.3
Bajocian 168.3 170.3
Aalenian 170.3 174.1
Lower/
Early
Toarcian 174.1 182.7
Pliensbachian 182.7 190.8
Sinemurian 190.8 199.3
Hettangian 199.3 201.3
Triassic Upper/
Late
Rhaetian older
Subdivision of the Jurassic system
according to the ICS, as of 2017.[1]

Stratigraphic definitions

Péry-Reuchenette Oxfordian
Cyclically alternating limestone (light, more competent) and marl/clay layers of Oxfordian age at Péry-Reuchenette, near Tavannes, Jura Mountains, Switzerland.

The Oxfordian stage was called "Clunch Clay and Shale" by William Smith (1815–1816); in 1818 W. Buckland described them under the unwieldy title "Oxford, Forest or Fen Clay". The term Oxfordian was introduced by Alcide d'Orbigny in 1844. The name is derived from the English city of Oxford,[3] where the beds are well developed, but they crop out almost continuously from Dorset to the coast of Yorkshire, generally forming low, broad valleys. They are well exposed at Weymouth, Oxford, Bedford, Peterborough, and in the cliffs at Scarborough, Red Cliff and Gristhorpe Bay. Rocks of this age are found also in Uig and Skye.[4]

The base of the Oxfordian stage is defined as the point in the stratigraphic record where the ammonite species Brightia thuouxensis first appears. A global reference profile for the base (a GSSP) had in 2009 not yet been assigned. The top of the Oxfordian stage (the base of the Kimmeridgian) is at the first appearance of ammonite species Pictonia baylei.

In the Tethys domain, the Oxfordian contains six ammonite biozones:

Palaeontology

†Sauropods

Sauropods of the Oxfordian
Taxa Presence Location Description Images
Bathonian-Oxfordian Originally thought to have lived form the Hauterivian to Barremian.

†Ornithischians

Chaoyangsaurus BW
Chaoyangsaurus
Chialingosaurus BW
Chialingosaurus
Chungkingosaurus jiangbeiensis
Chungkingosaurus
Dacentrurus
Dacentrurus
Tuojiangosaurus
Tuojiangosaurus
Yinlong BW
Yinlong

†Plesiosaurians

Plesiosaurians of the Oxfordian
Taxa Presence Location Description Images
Bajocian-Tithonian

†Thalattosuchians

Metriorhynchus BW
Metriorhynchus, a marine crocodilian.

Theropods

Yanchuanosaurus1
Yangchuanosaurus

Cephalopods

BelemnitesJurassicWyoming
Belemnite fossils
Cameroceras trentonese
An illustration of a variety of fossil nautiloids.

References

Notes

  1. ^ http://www.stratigraphy.org/index.php/ics-chart-timescale
  2. ^ For a detailed geologic timescale see Gradstein et al. (2004)
  3. ^ Oxfordian is a word meaning "from Oxford" (see wiktionary:Oxfordian).
  4. ^  One or more of the preceding sentences incorporates text from a publication now in the public domainHowe, John Allen (1911). "Oxfordian". In Chisholm, Hugh (ed.). Encyclopædia Britannica. 20 (11th ed.). Cambridge University Press. p. 415.

Literature

  • Brongniart, A.; 1829: Tableau théorique de la succession et de la disposition la plus générale on Europa, des terrains et roches, qui composent l'écorce de la terre, Paris.(in French)
  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.

External links

Almadasuchus

Almadasuchus is an extinct genus of crocodylomorph known from the early Late Jurassic (early Oxfordian stage) Puesto Almada Member of the Cañadón Asfalto Formation of Patagonia, Argentina. It contains a single species, Almadasuchus figarii. It is known from the holotype MPEF-PV 3838, a well-preserved posterior region of the skull as well as other skull and postcranial remains.

Ampthill Clay

The Ampthill Clay is a Mesozoic geologic formation in southern England. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.

Anguanax

Anguanax is an extinct genus of basal pliosaurid known from the Late Jurassic (Oxfordian stage) Rosso Ammonitico Veronese Formation of northern Italy. It contains a single species, Anguanax zignoi, known from a partially complete individual, representing the first articulated skeleton of an Italian plesiosaurian.

Camadas de Montejunto

The Camadas de Montejunto is an Oxfordian geologic formation in Portugal. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.

Chacarilla Formation

The Chacarilla Formation (Spanish: Formación Characilla) is an Oxfordian to Early Cretaceous geologic formation of the Tarapacá Basin in northern Chile, close to the border with Bolivia. The marine and fluvial formation preserves several dinosaur trackways and has been declared a Natural Sanctuary (Spanish: Santuario de la Naturaleza) in 2004.

Corallian Oolite Formation

The Corallian Oolite Formation is a geological formation in Europe. It dates back to the Late Jurassic.

Ellis Group

The Ellis Group is a stratigraphical unit of Bajocian-Oxfordian age in Alberta, Sakatchewan, Montana and Wyoming in the Western Canadian Sedimentary Basin. It takes the name from Fort Ellis, Montana, and was first described in outcrop in the Rocky Creek Canyon by A.C. Peale in 1893.

Entrada Sandstone

The Entrada Sandstone is a formation in the San Rafael Group found in the U.S. states of Wyoming, Colorado, northwest New Mexico, northeast Arizona, and southeast Utah. Part of the Colorado Plateau, this formation was deposited during the Jurassic period sometime between 180 and 140 million years ago in various environments, including tidal mudflats, beaches, and sand dunes. The Middle Jurassic San Rafael Group was dominantly deposited as ergs (sand seas) in a desert environment around the shallow Sundance Sea.

Guanlong

Guanlong (冠龍) is a genus of extinct proceratosaurid tyrannosauroid from the Late Jurassic of China. The taxon was first described in 2006 by Xu Xing et al., who found it to represent a new taxon related to Tyrannosaurus. The name is derived from Chinese, translating as "five colored crowned dragon". Two individuals are currently known, a partially complete adult and a nearly complete juvenile. These specimens come from the Oxfordian stage of the Chinese Shishugou Formation.

Ionia Formation

The Ionia Formation is a geologic formation in Michigan. It preserves fossils dating back to the Jurassic period.

Jagua Formation

The Jagua Formation is a Late Jurassic (middle to late Oxfordian) geologic formation in the Sierra de los Órganos and Sierra del Rosario mountain ranges in Pinar del Río Province, western Cuba. Plesiosaur, pliosaur, pterosaur, metriorhynchid, and turtle remains are among the fossils that have been recovered from its strata.

Kugitang Svita Formation

The Kugitang Svita Formation is a Mesozoic geologic formation in Turkmenistan. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.

Les Sables de Glos Formation

The Les Sables de Glos Formation is a sandy Mesozoic geologic formation in France. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.

Nacientes del Teno Formation

Nacientes del Teno Formation (Spanish: Formación Nacientes del Teno) is a geological formation that crops out near the uppermost reaches of Teno River, in the Andes of central Chile. The formation is similar to Nacientes del Biobío Formation further south.

Qigu Formation

The Qigu Formation is a Mesozoic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation most notably those of Xinjiangtitan. Pterosaur fossils have been recovered from the formation.

The "enormous" accumulation of Jurassic freshwater turtle fossils discovered in 2009 at a site nicknamed "Mesa Chelonia" in Shanshan County, Xinjiang is thought to likely belong to the Qigu Formation.

Tiourarén Formation

The Tiourarén Formation is a geological formation in the Agadez Region of Niger whose strata were originally thought to be Early Cretaceous. However, re-interpretation of the sediments showed that they are probably Middle Jurassic (Bathonian) in age. It is the uppermost unit of the Irhazer Group. Dinosaur remains are among the fossils that have been recovered from the formation.

Upware South Pit

Upware South Pit is a 1.1 hectare geological Site of Special Scientific Interest (SSSI) north of Upware in Cambridgeshire. It is a Geological Conservation Review site.This site has rocks dating to the Oxfordian stage, around 160 million years ago. It was then a coral reef, and has fossils of bivalves and ammonites, as well as corals, which show affinities with the fauna of the Tethys Ocean. It is described by Natural England as a key site in study of the Oxfordian.There is access to the site from the Fen Rivers Way north of Upware. A small area of pasture in the north of the site, which is not open to the public, is also part of the Cam Washes biological SSSI.

Villigen Formation

The Villigen Formation is a Mesozoic geologic formation in Switzerland. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.

Zuolong

Zuolong (Zuo's dragon) is a genus of coelurosaur dinosaur which existed in what is now Wucaiwan, Xinjiang Autonomous Region of China during the Late Jurassic period (lower Oxfordian stage, around 160 mya).

Cenozoic era
(present–66.0 Mya)
Mesozoic era
(66.0–251.902 Mya)
Paleozoic era
(251.902–541.0 Mya)
Proterozoic eon
(541.0 Mya–2.5 Gya)
Archean eon (2.5–4 Gya)
Hadean eon (4–4.6 Gya)

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