The Pliensbachian is an age of the

geologic timescale The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronol ...

and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 190.8 ± 1.5 Ma and 182.7 ± 1.5 Ma (million years ago). The Pliensbachian is preceded by the Sinemurian and followed by the Toarcian. The Pliensbachian ended with the

extinction event An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...

called the Toarcian turnover. During the Pliensbachian, the middle part of the Lias was deposited in Europe. The Pliensbachian is roughly coeval with the Charmouthian regional stage of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

Stratigraphic definitions

The Pliensbachian takes its name from the hamlet of Pliensbach in the community of Zell unter Aichelberg in the

Swabian Alb The Swabian Jura (german: Schwäbische Alb , more rarely ), sometimes also named Swabian Alps in English, is a mountain range in Baden-Württemberg, Germany, extending from southwest to northeast and in width. It is named after the region of ...

, some 30 km east of

Stuttgart Stuttgart (; Swabian: ; ) is the capital and largest city of the German state of Baden-Württemberg. It is located on the Neckar river in a fertile valley known as the ''Stuttgarter Kessel'' (Stuttgart Cauldron) and lies an hour from the ...

in Germany. The name was introduced into scientific literature by German palaeontologist Albert Oppel in 1858. The base of the Pliensbachian is at the first appearances of the ammonite species '' Bifericeras donovani'' and

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

'' Apoderoceras'' and ''

Gleviceras ''Gleviceras'' is an ammonite genus (order Ammonitida) that lived during the Early Jurassic Period, found in Canada, Hungary, Mexico and the United Kingdom. ''Glevumites'' Buckman 1924, ''Guibaliceras'' Buckman 1918, ''Riparioceras'' Schindewo ...

''. The Wine Haven profile near Robin Hood's Bay ( Yorkshire, England) has been appointed as global reference profile for the base ( GSSP).Meister ''et al.'' (2006) The top of the Pliensbachian (the base of the Toarcian Stage) is at the first appearance of ammonite genus '' Eodactylites''.

Biostratigraphy

The Pliensbachian contains five ammonite biozones in the

boreal domain Boreal may refer to: Climatology and geography *Boreal (age), the first climatic phase of the Blytt-Sernander sequence of northern Europe, during the Holocene epoch *Boreal climate, a climate characterized by long winters and short, cool to mild ...

: *zone of ''

Pleuroceras spinatum ''Pleuroceras spinatum'' is a species of ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to l ...

'' *zone of '' Amaltheus margaritatus'' *zone of '' Prodactylioceras davoei'' *zone of '' Tragophylloceras ibex'' *zone of '' Uptonia jamesoni'' In the Tethys domain, the Pliensbachian contains six biozones: *zone of '' Emaciaticeras emaciatum'' *zone of '' Arieticeras algovianum'' *zone of '' Fuciniceras lavinianum'' *zone of ''Prodactylioceras davoei'' *zone of ''Tragophylloceras ibex'' *zone of ''Uptonia jamesoni''

References

Notes

Literature

*; 2004: ''A Geologic Time Scale 2004'', Cambridge University Press. *; 2002: ''The Lower Lias of Robin Hood's Bay, Yorkshire, and the work of Leslie Bairstow'', Bulletin of the Natural History Museum. Geology Series 58, p. 81–152, Cambridge University Press, The Natural History Museum,
abstract
*; 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), pp. 93–106. *; 1856-1858: ''Die Juraformation Englands, Frankreichs und des südwestlichen Deutschlands: nach ihren einzelnen Gliedern engetheilt und verglichen'', 857 pp., Ebner & Seubert, Stuttgart.

External links

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 {{Geological history, p, m *03 Geological ages