Sinemurian
| Sinemurian | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Jurassic rock strata in the cliffs atEast Quantoxhead,near the Sinemuriangolden spike. | |||||||||
| Chronology | |||||||||
| |||||||||
| Etymology | |||||||||
| Name formality | Formal | ||||||||
| Usage information | |||||||||
| Celestial body | Earth | ||||||||
| Regional usage | Global (ICS) | ||||||||
| Time scale(s) used | ICS Time Scale | ||||||||
| Definition | |||||||||
| Chronological unit | Age | ||||||||
| Stratigraphic unit | Stage | ||||||||
| Time span formality | Formal | ||||||||
| Lower boundary definition | FADof theAmmonitesVermiceras quantoxenseandVermiceras palmeri | ||||||||
| Lower boundary GSSP | East Quantoxhead,West Somerset,England,UK 51°11′27″N3°14′11″W/ 51.1909°N 3.2364°W | ||||||||
| Lower GSSP ratified | 2000[2] | ||||||||
| Upper boundary definition | FAD of the Ammonite speciesBifericeras donovaniand genusApoderoceras | ||||||||
| Upper boundary GSSP | Robin Hood's Bay,Yorkshire,England, UK 54°24′25″N0°29′51″W/ 54.4069°N 0.4975°W | ||||||||
| Upper GSSP ratified | March 2005[3] | ||||||||
In thegeologic timescale,theSinemurianis anageandstagein theEarly or Lower JurassicEpochorSeries.It spans the time between 199.5 ±0.3Maand 192.9 ±0.3 Ma (million years ago).[4]The Sinemurian is preceded by theHettangianand is followed by thePliensbachian.[5]
In Europe the Sinemurian age, together with the Hettangian age, saw the deposition of the lowerLias,in Great Britain known as theBlue Lias.
Stratigraphic definitions
[edit]The Sinemurian Stage was defined and introduced into scientific literature by French palaeontologistAlcide d'Orbignyin 1842. It takes its name from the French town ofSemur-en-Auxois,nearDijon.Thecalcareoussoil formed from the Jurassiclimestoneof the region is in part responsible for the character of the classicSancerre wines.
The base of the Sinemurian Stage is at the first appearance of theammonitegeneraVermicerasandMetophiocerasin the stratigraphic record. A global reference profile (GSSP or golden spike) for the Sinemurian Stage is located in a cliff north of the hamlet ofEast Quantoxhead,6 kilometers (3.7 mi) east ofWatchet,Somerset,England.[6]
The top of the Sinemurian (the base of the Pliensbachian) is at the first appearances of the ammonite speciesBifericeras donovaniand ammonite genusApoderoceras.
The Sinemurian contains six ammonitebiozonesin theTethys domain:
- zone ofEchioceras raricostatum
- zone ofOxynoticeras oxynotum
- zone ofAsteroceras obtusum
- zone ofCaenisites turneri
- zone ofArnioceras semicostatum
- zone ofArietites bucklandi
References
[edit]- ^"International Chronostratigraphic Chart"(PDF).International Commission on Stratigraphy.
- ^Bloos, Gert; Page, Kevin (March 2002)."Global Stratotype Section and Point for base of the Sinemurian Stage (Lower Jurassic)".Episodes.25(1): 22–28.doi:10.18814/epiiugs/2002/v25i1/003.Retrieved23 December2020.
- ^Meister, Christian; Aberhan, Martin; Blau, Joachim; Dommergues, Jean-Louis; Feist-Burkhardt, Susanne; Hailwood, Ernie; Hart, Malcolm; Hesselbo, Stephen; Hounslow, Mark; Hylton, Mark; Martin, Nicol; Page, Kevin; Price, Greg (June 2006)."The Global Boundary Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic), Wine Haven, Yorkshire, UK".Episodes.29(2): 93–106.doi:10.18814/epiiugs/2006/v29i2/003.Retrieved23 December2020.
- ^Benton, Michael J. (2012).Prehistoric Life.Edinburgh, Scotland: Dorling Kindersley. pp. 44–45.ISBN978-0-7566-9910-9.
- ^For a detailed geologic timescale see Gradsteinet al.(2004)
- ^See for the description of the GSSP Bloos & Page (2001)
Sources
[edit]- Bloos, G. & Page, K.N.;2001:Global Stratotype Section and Point for base of the Sinemurian Stage (Lower Jurassic),Episodes25(1),pp. 22–28,PDF
- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.;2004:A Geologic Time Scale 2004,Cambridge University Press.
- d´Orbigny, A.C.V.M.D.;1842:Paléontologie française. 1. Terrains oolitiques ou jurassiques,Bertrand, Paris.(in French)
See also
[edit]External links
[edit]- GeoWhen Database - Sinemurian
- Lower 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
