| Sinemurian | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 199.5 ± 0.3 – 192.9 ± 0.3Ma | |||||||||
 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 | FAD of theAmmonitesVermiceras quantoxense andVermiceras palmeri | ||||||||
| Lower boundary GSSP | East Quantoxhead,West Somerset,England,UK 51°11′27″N3°14′11″W / 51.1909°N 3.2364°W /51.1909; -3.2364 | ||||||||
| Lower GSSP ratified | 2000[2] | ||||||||
| Upper boundary definition | FAD of the Ammonite speciesBifericeras donovani and genusApoderoceras | ||||||||
| Upper boundary GSSP | Robin Hood's Bay,Yorkshire, England, UK 54°24′25″N0°29′51″W / 54.4069°N 0.4975°W /54.4069; -0.4975 | ||||||||
| Upper GSSP ratified | March 2005[3] | ||||||||
In thegeologic timescale, theSinemurian is anage andstage in theEarly or Lower JurassicEpoch orSeries. It spans the time between 199.5 ±0.3Ma and 192.9 ±0.3 Ma (million years ago).[4] The Sinemurian is preceded by theHettangian and 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.
The Sinemurian Stage was defined and introduced into scientific literature by French palaeontologistAlcide d'Orbigny in 1842. It takes its name from the French town ofSemur-en-Auxois, nearDijon. Thecalcareous soil formed from the Jurassiclimestone of 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 theammonitegeneraVermiceras andMetophioceras 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 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 donovani and ammonite genusApoderoceras.
The Sinemurian contains six ammonitebiozones in theTethys domain:
