In the

geologic timescale The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochron ...

, the Sinemurian is an

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

and stage in the Early or Lower Jurassic

Epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

Series Series may refer to: People with the name * Caroline Series (born 1951), English mathematician, daughter of George Series * George Series (1920–1995), English physicist Arts, entertainment, and media Music * Series, the ordered sets used i ...

. It spans the time between 199.5 ±0.3 Ma and 192.9 ±0.3 Ma (million years ago). The Sinemurian is preceded by the

Hettangian The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma (million years ago). The Hettangian follows the Rhaetian (part of the Triass ...

and is followed by the Pliensbachian. In Europe the Sinemurian age, together with the Hettangian age, saw the deposition of the lower Lias, in Great Britain known as the

Blue Lias The Blue Lias is a formation (stratigraphy), geological formation in southern, eastern and western England and parts of South Wales, part of the Lias Group. The Blue Lias consists of a sequence of limestone and shale layers, laid down in latest ...

Stratigraphic definitions

The Sinemurian Stage was defined and introduced into scientific literature by French palaeontologist

Alcide d'Orbigny Alcide Charles Victor Marie Dessalines d'Orbigny (6 September 1802 – 30 June 1857) was a French naturalist who made major contributions in many areas, including zoology (including malacology), palaeontology, geology, archaeology and anthropol ...

in 1842. It takes its name from the French town of

Semur-en-Auxois Semur-en-Auxois () is a Communes of France, commune of the Côte-d'Or Departments of France, department in eastern France. The politician François Patriat, the engineers Edmé Régnier L'Aîné (1751–1825) and Émile Dorand (1866-1922), and th ...

, near

Dijon Dijon (, ; ; in Burgundian language (Oïl), Burgundian: ''Digion'') is a city in and the Prefectures in France, prefecture of the Côte-d'Or Departments of France, department and of the Bourgogne-Franche-Comté Regions of France, region in eas ...

. The

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

soil formed from the Jurassic

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

of the region is in part responsible for the character of the classic Sancerre wines. The base of the Sinemurian Stage is at the first appearance of the

ammonite Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

'' Vermiceras'' and '' Metophioceras'' in the stratigraphic record. A global reference profile ( GSSP or golden spike) for the Sinemurian Stage is located in a cliff north of the hamlet of

East Quantoxhead East Quantoxhead is a village, from West Quantoxhead, east of Williton, and west of Bridgwater, within the Quantock Hills Area of Outstanding Natural Beauty in Somerset, England. History Above the village at Black Ball Camp are an Iron Age ...

, east of Watchet,

Somerset Somerset ( , ), Archaism, archaically Somersetshire ( , , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by the Bristol Channel, Gloucestershire, and Bristol to the north, Wiltshire to the east ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

.See for the description of the GSSP Bloos & Page (2001) Eteoderoceras armatum sinemurian

The top of the Sinemurian (the base of the Pliensbachian) is at the first appearances of the ammonite species '' Bifericeras donovani'' and ammonite genus '' Apoderoceras''. The Sinemurian contains six ammonite

biozone In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxon, taxa, as opposed to a Lithostratigraphy, lithostratigraphic unit which is defined by the ...

s in the Tethys domain: *zone of '' Echioceras raricostatum'' *zone of '' Oxynoticeras oxynotum'' *zone of '' Asteroceras obtusum'' *zone of '' Caenisites turneri'' *zone of '' Arnioceras semicostatum'' *zone of '' Arietites bucklandi''

References

Sources

*; 2001: ''Global Stratotype Section and Point for base of the Sinemurian Stage (Lower Jurassic)'', Episodes 25(1), pp. 22–28
PDF
*; 2004: ''A Geologic Time Scale 2004'',

Cambridge University Press Cambridge University Press was the university press of the University of Cambridge. Granted a letters patent by King Henry VIII in 1534, it was the oldest university press in the world. Cambridge University Press merged with Cambridge Assessme ...

. *; 1842: ''Paléontologie française. 1. Terrains oolitiques ou jurassiques'', Bertrand, Paris.

External links

GeoWhen Database - SinemurianLower Jurassic timescale
at the website of the subcommission for stratigraphic information of the ICS
Stratigraphic chart of the Lower Jurassic
at the website of Norges Network of offshore records of geology and stratigraphy {{Geological history, p, m *02 Geological ages

Stratigraphic definitions

References

Sources

See also

External links