The Pliensbachian is an age of the geologic timescale or stage in the stratigraphic column. It is part of the Early or Lower Jurassic

Early Jurassic

The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...

 epoch

Epoch (geology)

An epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...

 or series

Series (stratigraphy)

Series are subdivisions of rock layers made based on the age of the rock and corresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a...

 and spans the time between 189.6 ± 1.5 Ma and 183 ± 1.5 Ma (million years ago). The Pliensbachian is preceded by the Sinemurian

Sinemurian

In the geologic timescale, the Sinemurian is an age or stage in the Early or Lower Jurassic epoch or series. It spans the time between 196.5 ± 2 Ma and 189.6 ± 1.5 Ma...

 and followed by the Toarcian

Toarcian

The Toarcian is, in the ICS' geologic timescale, an age or stage in the Early or Lower Jurassic. It spans the time between 183.0 Ma and 175.6 Ma...

.

The Pliensbachian ended with the extinction event

Extinction event

An extinction event is a sharp decrease in the diversity and abundance of macroscopic life. They occur when the rate of extinction increases with respect to the rate of speciation...

 called the Toarcian turnover

Toarcian turnover

The term Toarcian turnover, alternatively the Toarcian extinction, the Pliensbachian-Toarcian extinction, or the Early Jurassic extinction, refers to the wave of extinctions that marked the end of the Pliensbachian stage and the start of the Toarcian stage of the Early Jurassic period, c...

. During the Pliensbachian, the middle part of the Lias

Lias

Lias may refer to:*In geology:**The Lias Group, a group in the stratigraphy of Great Britain, formed during the Late Triassic to Early Jurassic epochs. It includes the Blue Lias and White Lias...

 was deposited in Europe. The Pliensbachian is roughly coeval with the Charmouthian regional stage of North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

.

Stratigraphic definitions

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

Zell unter Aichelberg

Zell unter Aichelberg is a town in the district of Göppingen in Baden-Württemberg in southern Germany....

 in the Swabian Alb

Swabian Alb

The Swabian Alps or Swabian Jura is a low mountain range in Baden-Württemberg, Germany, extending 220 km from southwest to northeast and 40 to 70 km in width. It is named after the region of Swabia....

, some 30 km east of Stuttgart

Stuttgart

Stuttgart is the capital of the state of Baden-Württemberg in southern Germany. The sixth-largest city in Germany, Stuttgart has a population of 600,038 while the metropolitan area has a population of 5.3 million ....

 in Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

. The name was introduced into scientific literature by German palaeontologist Albert Oppel

Albert Oppel

Carl Albert Oppel was a German paleontologist.-History:He was born at Hohenheim in Württemberg, on December 19, 1831. He first went to the University of Tübingen, where he graduated with a Ph.D. in 1853. The results of his work was published in Die Juraformation Englands, Frankreichs and des...

 in 1858.

The base of the Pliensbachian is at the first appearances of the ammonite species Bifericeras donovani

Bifericeras

Bifericeras is a Lower Jurassic ammonite beloning to the family Eoderoceratidae, and sometimes placed in the subfamily Xipherceratinae. Whorls are strongly depressed, but still evolute in coiling...

and genera

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Apoderoceras

Apoderoceras

Apoderoceras is an extinct genus of cephalopod belonging to the Ammonite subclass....

and Gleviceras

Gleviceras

Gleviceras is a psiloceratacean ammonite included in the Lower Jurassic Oxynoticeratidae. Gleviceras is evolute, with a deep umbilicus, and strongly ribbed along the flanks.-References:* Joachim Blau. et al...

. The Wine Haven profile near Robin Hood's Bay

Robin Hood's Bay

Robin Hood’s Bay is a small fishing village and a bay located five miles south of Whitby and 15 miles north of Scarborough on the coast of North Yorkshire, England. Bay Town, its local name, is in the ancient chapelry of Fylingdales in the wapentake of Whitby Strand.-Toponymy:The origin of the name...

 (Yorkshire

Yorkshire

Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

) has been appointed as global reference profile for the base (GSSP).

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 biozone

Biozone

Biostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....

s in the boreal domain:

• zone of Pleuroceras spinatum
• zone of Amaltheus margaritatus
  Amaltheus
  Amaltheus is an oxyconic ammonite with a fairly open umbilicus, serrated keel, and slightly sigmoidal ribs from the Lower Jurassic, many of which are strigate. Amaltheus, named by de Montfort ,1808, is indicative of the upper Pliensbachian stage in Europe, north Africa, Caucasus, Siberia, N...
  
  
• zone of Prodactylioceras davoei
• zone of Tragophylloceras ibex
• zone of Uptonia jamesoni
  Uptonia
  Uptonia is an extinct ammonite from the Lower Jurassic that's included in the eoderoceratacean family Polymorphitidae.The shell of Uptonia is evolute with rounded simple ribs that form strong chevrons as they cross the venter on the outer rim, and which are free of tubercles. Some grew to be fairly...
  
  

In the Tethys domain

Tethys Ocean

The Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...

, the Pliensbachian contains six biozones:

• zone of Emaciaticeras emaciatum
• zone of Arieticeras algovianum
  Arieticeras
  Arieticeras is an extinct genus of cephalopod belonging to the Ammonite subclass....
  
  
• zone of Fuciniceras lavinianum
  Fuciniceras
  Fuciniceras is an extinct cephalopod genus belonging to the ammonoid subclass, included in the ammonite family Hildoceratidae, that lived during the latter part of the Early Jurassic.-References:*...
  
  
• zone of Prodactylioceras davoei
• zone of Tragophylloceras ibex
• zone of Uptonia jamesoni

†Ornithischians

Ornithischians of the Pliensbachian
Taxa	Presence	Location	Description	Images
Bienosaurus Bienosaurus Bienosaurus was a dinosaur from the Early Jurassic. The genus was an armoured dinosaur from the Lower Lufeng Formation in Yunnan Province in China.-Discovery and species:...		Lower Lufeng Formation, Yunnan, China	A dubious basal thyreophora Thyreophora The Thyreophora were a subgroup of the ornithischian dinosaurs... n
Tatisaurus Tatisaurus Tatisaurus is a genus of ornithischian dinosaur from the Early Jurassic from the Lower Lufeng Formation in Yunnan Province in China. Little is known as the remains are fragmentary.-Discovery and species:...		Lower Lufeng Formation, Yunnan, China	Description based on only a partial left mandible with teeth, a dubious basal thyreophora Thyreophora The Thyreophora were a subgroup of the ornithischian dinosaurs... n

Theropoda

Theropods of the Pliensbachian
Taxa	Presence	Location	Description	Images
Cryolophosaurus Cryolophosaurus Cryolophosaurus was a large theropod dinosaur, with a crest on its head that looked like a Spanish comb. Due to the resemblance of this feature to Elvis Presley's pompadour haircut from the 1950s, this dinosaur was at one point informally known as "Elvisaurus".Cryolophosaurus was excavated from...		Hanson Formation, Antarctica	The earliest known tetanuran. About 6 to 8 meters (20 to 26 feet) long with a high, narrow skull and a peculiar nasal crest just over the eyes
Dilophosaurus Dilophosaurus Dilophosaurus was a theropod dinosaur from the Sinemurian stage of the Early Jurassic Period, about 193 million years ago. The first specimens were described in 1954, but it was not until over a decade later that the genus received its current name...	Sinemurian Sinemurian In the geologic timescale, the Sinemurian is an age or stage in the Early or Lower Jurassic epoch or series. It spans the time between 196.5 ± 2 Ma and 189.6 ± 1.5 Ma...  to Pliensbachian	Arizona Arizona Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix... , USA; Yunnan Yunnan Yunnan is a province of the People's Republic of China, located in the far southwest of the country spanning approximately and with a population of 45.7 million . The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.Yunnan is situated in a mountainous area, with... , China	Measured around six meters (20 ft) long and may have weighed half a ton. The most distinctive characteristic of Dilophosaurus is the pair of rounded crests on its skull, possibly used for display.

Literature

; 2004: A Geologic Time Scale 2004, Cambridge University Press

Cambridge University Press

Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

.; 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

• GeoWhen Database - Pliensbachian
• 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