| Pliensbachian | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 192.9 ± 0.3 – 184.2 ± 0.3Ma | |||||||||
| 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 theAmmonite speciesBifericeras donovani and genusApoderoceras | ||||||||
| Lower 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 | ||||||||
| Lower GSSP ratified | March 2005[2] | ||||||||
| Upper boundary definition | Peniche, Portugal | ||||||||
| Upper boundary GSSP | FAD of the AmmoniteD. (E.) simplex 39°22′15″N9°23′07″W / 39.3708°N 9.3853°W /39.3708; -9.3853 | ||||||||
| Upper GSSP ratified | 2014[3] | ||||||||
ThePliensbachian is anage of thegeologic timescale andstage in the stratigraphic column. It is part of theEarly or Lower JurassicEpoch orSeries and spans the time between 192.9 ±0.3Ma and 184.2 ±0.3 Ma (million years ago).[4] The Pliensbachian is preceded by theSinemurian and followed by theToarcian.[5]
The Pliensbachian ended with theextinction event called theToarcian turnover. During the Pliensbachian, the middle part of theLias was deposited in Europe. The Pliensbachian is roughly coeval with theCharmouthian regional stage ofNorth America.
The Pliensbachian takes its name from the hamlet ofPliensbach in the community ofZell unter Aichelberg in theSwabian Alb, some 30 km east ofStuttgart inGermany. The name was introduced into scientific literature by German palaeontologistAlbert Oppel in 1858.
The base of the Pliensbachian is at the first appearances of the ammonite speciesBifericeras donovani andgeneraApoderoceras andGleviceras. The Wine Haven profile nearRobin Hood's Bay (Yorkshire,England) has been appointed as global reference profile for the base (GSSP).[6]
The top of the Pliensbachian (the base of the Toarcian Stage) is at the first appearance of ammonite genusEodactylites.
The Pliensbachian contains five ammonitebiozones in theboreal domain:
In theTethys domain, the Pliensbachian contains six biozones:
