Wordian

In the geologic timescale, the Wordian is an age or stage of the Permian. It is the middle of three subdivisions of the Guadalupian epoch or series. The Wordian lasted between 268.8 and 265.1 million years ago (Ma). It was preceded by the Roadian and followed by the Capitanian.[2]

System/
Period		 Series/
Epoch		 Stage/
Age		 Age (Ma)
Triassic Lower/
Early		 Induan younger
Permian Lopingian Changhsingian 251.902 254.14
Wuchiapingian 254.14 259.1
Guadalupian Capitanian 259.1 265.1
Wordian 265.1 268.8
Roadian 268.8 272.95
Cisuralian Kungurian 272.95 283.5
Artinskian 283.5 290.1
Sakmarian 290.1 295.0
Asselian 295.0 298.9
Carboniferous Pennsylvanian Gzhelian older
Subdivision of the Permian system
according to the ICS, as of 2017.[1]

Stratigraphy

The Wordian stage was introduced into scientific literature by Johan August Udden in 1916 and was named after the Word Formation of the North American Permian Basin. The Wordian was first used as a stratigraphic subdivision of the Guadalupian in 1961,[3] when both names were still only used regionally in the southern US. The stage was added to the internationally used ISC timescale in 2001.[4]

The base of the Wordian stage is defined as the place in the stratigraphic record where fossils of conodont species Jinogondolella aserrata first appear. The global reference profile for this stratigraphic boundary is located at Getaway Ledge in the Guadalupe Mountains of Texas.

The top of the Wordian (the base of the Capitanian stage) is defined as the place in the stratigraphic record where the conodont species Jinogondolella postserrata first appears.

The Wordian stage was part of the time in which the Zechstein was deposited in Europe.

Biostratigraphy

The Wordian spans the entire conodont biozone of Jinogondolella aserrata. It contains two fusulinid biozones:

  • Zone of Afganella tereshkovae
  • Zone of Neoschwagerina tenuis

Biodiversity

Olson’s Extinction, a worldwide loss of terrestrial vertebrate life occurred during the Early Guadalupian (Roadian, Wordian).[5]

Wordian life

Actinopterygians
Actinopterygii of the Wordian
Taxa Presence Location Description Images
Carboniferous to Lopingian Russia A non-neopterygian
Platysomus
  • Varialepis
 Permian Russia A non-neopterygian


Diapsids
Diapsida of the Wordian
Taxa Presence Location Description Images
Guadalupian Russia A neodiapsid
Lanthanolania

Synapsids (non-therapsid)
Synapsida of the Wordian
Taxa Presence Location Description Images
Guadalupian Russia A caseasaurian
Ennatosaurus

Therapsids
Therapsida of the Wordian
Taxa Presence Location Description Images
Guadalupian Perm Krai, Russia A biarmosuchian therapsid
Biarmosuchus
Eodicynodon
Estemmenosuchus
Parabradysaurus
Guadalupian South Africa A dicynodont therapsid
Guadalupian Perm Krai, Russia A biarmosuchian therapsid
Guadalupian Russia A dinocephalian therapsid
Guadalupian Russia A biarmosuchian therapsid
Guadalupian Russia A dinocephalian therapsid
Guadalupian South Africa A anomodont therapsid
Guadalupian Russia A phthinosuchid therapsid
Guadalupian South Africa A dinocephalian therapsid

References
  1. "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
  2. Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press
  3. Glenister, B.F. & Furnish, W.M.; 1961: The Permian ammonoids of Australia, Journal of Paleontology 35(4), pp 673–736.
  4. Glenister, B.F.; Wardlaw, B.R.; Lambert, L.L.; Spinosa, C.; Bowring, S.A.; Erwin, D.H.; Menning, M. & Wilde, G.L.; 1999: Proposal of Guadalupian and Component Roadian, Wordian and Capitanian Stages as International Standards for the Middle Permian Series, Permophiles 34: pp 3–11.
  5. Sahney, S. & Benton, M.J. (2008). "Recovery from the most profound mass extinction of all time" (PDF). Proceedings of the Royal Society B: Biological Sciences. 275 (1636): 759–65. doi:10.1098/rspb.2007.1370. PMC 2596898. PMID 18198148.

Literature
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.