View source for Sinemurian

{{short description|Second age of the Early Jurassic}}
{{Infobox geologic timespan
| name                         = Sinemurian
| color                        = Sinemurian
| time_start                   = 199.5
| time_start_uncertainty       = 0.3
| time_end                     = 192.9
| time_end_uncertainty         = 0.3
| image_map                    =
| caption_map                  =
| image_outcrop                = Cliff Face East Quantoxhead - geograph.org.uk - 1003272.jpg
| caption_outcrop              = Jurassic rock strata in the cliffs at [[East Quantoxhead]], near the Sinemurian [[Global Boundary Stratotype Section and Point|golden spike]].
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<!--Chronology-->
| timeline                     = Jurassic
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<!--Etymology-->
| name_formality               = Formal
| name_accept_date             =
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<!--Usage Information-->
| celestial_body               = earth
| usage                        = Global ([[International Commission on Stratigraphy|ICS]])
| timescales_used              = ICS Time Scale
| formerly_used_by             =
| not_used_by                  =
<!--Definition-->
| chrono_unit                  = Age
| strat_unit                   = Stage
| proposed_by                  =
| type_section                 =
| timespan_formality           = Formal
| lower_boundary_def           = [[First appearance datum|FAD]] of the [[Ammonites]]  ''[[Vermiceras|Vermiceras quantoxense]]'' and ''[[Vermiceras|Vermiceras palmeri]]''
| lower_gssp_location          = [[East Quantoxhead]], [[West Somerset]], [[England]], [[United Kingdom|UK]]
| lower_gssp_coords            = {{Coord|51.1909|N|3.2364|W|display=inline}}
| lower_gssp_accept_date       = 2000<ref>{{cite journal |last1=Bloos |first1=Gert |last2=Page |first2=Kevin |title=Global Stratotype Section and Point for base of the Sinemurian Stage (Lower Jurassic) |journal=Episodes |date=March 2002 |volume=25 |issue=1 |pages=22–28 |doi=10.18814/epiiugs/2002/v25i1/003 |url=https://www.researchgate.net/publication/237657998 |access-date=23 December 2020|doi-access=free }}</ref>
| upper_boundary_def           = FAD of the Ammonite species ''[[Bifericeras|Bifericeras donovani]]'' and genus ''[[Apoderoceras]]''
| upper_gssp_location          =  [[Robin Hood's Bay]], [[Yorkshire]], England, UK
| upper_gssp_coords            = {{Coord|54.4069|N|0.4975|W|display=inline}}
| upper_gssp_accept_date       = March 2005<ref>{{cite journal |last1=Meister |first1=Christian |last2=Aberhan |first2=Martin |last3=Blau |first3=Joachim |last4=Dommergues |first4=Jean-Louis |last5=Feist-Burkhardt |first5=Susanne |last6=Hailwood |first6=Ernie |last7=Hart |first7=Malcolm |last8=Hesselbo |first8=Stephen |last9=Hounslow |first9=Mark |last10=Hylton |first10=Mark |last11=Martin |first11=Nicol |last12=Page |first12=Kevin |last13=Price |first13=Greg |title=The Global Boundary Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic), Wine Haven, Yorkshire, UK |journal=Episodes |date=June 2006 |volume=29 |issue=2 |pages=93–106 |doi=10.18814/epiiugs/2006/v29i2/003 |url=https://www.researchgate.net/publication/228674790 |access-date=23 December 2020|doi-access=free }}</ref>
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}}
In the [[geologic timescale]], the '''Sinemurian''' is an [[age (geology)|age]] and [[stage (stratigraphy)|stage]] in the [[Early Jurassic|Early or Lower Jurassic]] [[epoch (geology)|Epoch]] or [[series (stratigraphy)|Series]]. It spans the time between 199.5 ±0.3 [[annum|Ma]] and 192.9 ±0.3 Ma (million years ago).<ref name="benton, 2012">{{cite book|last=Benton|first=Michael J.|title=Prehistoric Life|year=2012|publisher=Dorling Kindersley|location=Edinburgh, Scotland|isbn=978-0-7566-9910-9|pages=44–45}}</ref> The Sinemurian is preceded by the [[Hettangian]] and is followed by the [[Pliensbachian]].<ref>For a detailed geologic timescale see Gradstein ''et al.'' (2004)</ref>
In Europe the Sinemurian age, together with the Hettangian age, saw the deposition of the lower [[Lias Group|Lias]], in Great Britain known as the [[Blue Lias]].
==Stratigraphic definitions==
The Sinemurian Stage was defined and introduced into scientific literature by French palaeontologist [[Alcide d'Orbigny]] in 1842. It takes its name from the French town of [[Semur-en-Auxois]], near [[Dijon]]. The [[calcareous]] soil formed from the Jurassic [[limestone]] of the region is in part responsible for the character of the classic [[Sancerre (wine)|Sancerre wines]].
The base of the Sinemurian Stage is at the first appearance of the [[ammonite]] [[genus|genera]] ''[[Vermiceras]]'' and ''[[Metophioceras]]'' in the stratigraphic record. A global reference profile ([[GSSP|GSSP or golden spike]]) for the Sinemurian Stage is located in a cliff north of the hamlet of [[East Quantoxhead]], {{convert|6|km|sp=us}} east of [[Watchet]], [[Somerset]], [[England]].<ref>See for the description of the GSSP Bloos & Page (2001)</ref>
[[File:Eteoderoceras armatum sinemurian.jpg|thumb|left|''Eteoderoceras armatum'', a Sinemurian ammonite]]
The top of the Sinemurian (the base of the Pliensbachian) is at the first appearances of the ammonite species ''[[Bifericeras|Bifericeras donovani]]'' and ammonite genus ''[[Apoderoceras]]''.
The Sinemurian contains six ammonite [[biozone]]s in the [[Tethys Ocean|Tethys domain]]:
*zone of ''[[Echioceras|Echioceras raricostatum]]''
*zone of ''[[Oxynoticeras|Oxynoticeras oxynotum]]''
*zone of ''[[Asteroceras|Asteroceras obtusum]]''
*zone of ''[[Caenisites|Caenisites turneri]]''
*zone of ''[[Arnioceras|Arnioceras semicostatum]]''
*zone of ''[[Arietites|Arietites bucklandi]]''
== References ==
{{reflist}}
==Sources==
*{{aut|Bloos, G. & Page, K.N.}}; '''2001''': ''Global Stratotype Section and Point for base of the Sinemurian Stage (Lower Jurassic)'', Episodes '''25(1)''', pp.&nbsp;22–28, [https://web.archive.org/web/20100827025129/http://www.episodes.org/backissues/251/22-28%20Bloos.pdf PDF]
*{{aut|Gradstein, F.M.; Ogg, J.G. & Smith, A.G.}}; '''2004''': ''A Geologic Time Scale 2004'', [[Cambridge University Press]].
*{{aut|d´Orbigny, A.C.V.M.D.}}; '''1842''': ''Paléontologie française. 1. Terrains oolitiques ou jurassiques'', Bertrand, Paris. {{in lang|fr}}
=== See also ===
* [[Komlosaurus carbonis]]
==External links==
*[http://www.stratigraphy.org/bak/geowhen/stages/Sinemurian.html GeoWhen Database - Sinemurian]
*[http://stratigraphy.science.purdue.edu/charts/Timeslices/6_LowerJurassic.pdf Lower Jurassic timescale], at the website of the subcommission for stratigraphic information of the ICS
*[https://web.archive.org/web/20060518101459/http://norges.uio.no/timescale/Fig17.1_Jur_colB.pdf Stratigraphic chart of the Lower Jurassic], at the website of Norges Network of offshore records of geology and stratigraphy
{{Jurassic Footer}}
{{Geological history|p|m}}
[[Category:Sinemurian| ]]
[[Category:Early Jurassic|*02]]
[[Category:Geological ages]]