Sinemurian

EtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the AmmonitesVermiceras quantoxense and Vermiceras palmeriLower boundary GSSPEast Quantoxhead, West Somerset, England, UK
51°11′27″N3°14′11″W / 51.1909°N 3.2364°W / 51.1909; -3.2364Lower GSSP ratified2000Upper boundary definitionFAD of the Ammonite species Bifericeras donovani and genus ApoderocerasUpper boundary GSSPRobin Hood's Bay, Yorkshire, England, UK
54°24′25″N0°29′51″W / 54.4069°N 0.4975°W / 54.4069; -0.4975Upper GSSP ratifiedMarch 2005

In the geologic timescale, the Sinemurian is an age and stage in the Early or Lower JurassicEpoch or Series. 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 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.