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]
| 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] | ||||||||
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.
Stratigraphic definitions
editThe 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.
Biostratigraphy
edit
The Pliensbachian contains five ammonitebiozones in theboreal domain:
- zone ofPleuroceras spinatum
- zone ofAmaltheus margaritatus
- zone ofProdactylioceras davoei
- zone ofTragophylloceras ibex
- zone ofUptonia jamesoni
In theTethys domain, the Pliensbachian contains six biozones:
- zone ofEmaciaticeras emaciatum
- zone ofArieticeras algovianum
- zone ofFuciniceras lavinianum
- zone ofProdactylioceras davoei
- zone ofTragophylloceras ibex
- zone ofUptonia jamesoni
References
editNotes
edit- ^"International Chronostratigraphic Chart"(PDF).International Commission on Stratigraphy. December 2024. RetrievedJanuary 1, 2025.
- ^Meister, Christian; Aberhan, Martin; Blau, Joachim; Dommergues, Jean-Louis; Feist-Burkhardt, Susanne; Hailwood, Ernie; Hart, Malcolm; Hesselbo, Stephen; Hounslow, Mark; Hylton, Mark; Martin, Nicol; Page, Kevin; Price, Greg (June 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):93–106.doi:10.18814/epiiugs/2006/v29i2/003. Retrieved23 December 2020.
- ^da Rocha, Rogério Bordalo; Mattioli, Emanuela; Duarte, Luís Vítor; Pittet, Bernard; Elmi, Serge; Mouterde, René; Cabral, Maria Cristina; Comas-Rengifo, Maria José; Gómez, Juan José; Goy, António; Hesselbo, Stephen P.; Jenkyns, Hugh C.; Littler, Kate; Mailliot, Samuel; Veiga de Oliveira, Luiz Carlos; Osete, Maria Luisa; Nicola, Perilli; Pinto, Susana; Ruget, Christiane; Suan, Guillaume (September 2016)."Base of the Toarcian Stage of the Lower Jurassic defined by the Global Boundary Stratotype Section and Point (GSSP) at the Peniche section (Portugal)".Episodes.39 (3):460–481.doi:10.18814/epiiugs/2016/v39i3/99741.hdl:10261/140775.
- ^Benton, Michael J. (2012).Prehistoric Life. Edinburgh, Scotland: Dorling Kindersley. pp. 44–45.ISBN 978-0-7566-9910-9.
- ^See Gradsteinet al. (2004) for a detailed geologic timescale
- ^Meisteret al. (2006)
Literature
edit- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.;2004:A Geologic Time Scale 2004,Cambridge University Press.
- Howart, M.K.;2002:The Lower Lias of Robin Hood's Bay, Yorkshire, and the work of Leslie Bairstow, Bulletin of the Natural History Museum. Geology Series58, p. 81–152, Cambridge University Press, The Natural History Museum, (abstract)
- Meister, C.; Aberhan, M.; Blau, J.; Dommergues, J.-L.; Feist-Burkhardt, S.; Hailwood, E.A.; Hart, M.; Hesselbo, S.P.; Hounslow, M.W.; Hylton, M.; Morton, N.; Page, K & Price, G.D.;2006:The Global Boundary Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic), Wine Haven, Yorkshire, UK, Episodes29(2), pp. 93–106.
- Oppel, C.A.;1856-1858:Die Juraformation Englands, Frankreichs und des südwestlichen Deutschlands: nach ihren einzelnen Gliedern engetheilt und verglichen, 857 pp., Ebner & Seubert, Stuttgart.(in German)
External links
edit- 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