Capitanian

In the geologic timescale, the Capitanian is an age or stage of the Permian. It is also the uppermost or latest of three subdivisions of the Guadalupian epoch or series. The Capitanian lasted between 265.8 ± 0.7 Ma and 260.4 ± 0.7 million years ago (Ma). It was preceded by the Wordian and followed by the Wuchiapingian.[1]

A significant mass extinction event occurred at the end of this stage which may be related to the much larger Permian-Triassic extinction event that followed about 10 million years later.

The Capitanian stage was introduced into scientific literature by George Burr Richardson in 1904. The name comes from the Capitan Reef in the Guadalupe Mountains (Texas, USA). The Capitanian was first used as a stratigraphic subdivision of the Guadalupian in 1961,[2] when both names were still only used regionally in the southern US. The stage was added to the internationally used ISC timescale in 2001.[3]

Definitions

The base of the Capitanian stage is defined as the place in the stratigraphic record where fossils of conodont species Jinogondolella postserrata first appear. The global reference profile for this stratigraphic boundary is located at Nipple Hill in the southern Guadalupe Mountains of Texas.

The top of the Capitanian (the base of the Wuchiapingian and Lopingian series) is defined as the place in the stratigraphic record where the conodont species Clarkina postbitteri postbitteri first appears.

The Capitanian stage was part of the time in which the Zechstein was deposited in Europe. It is coeval with the old European regional Saxonian stage. In the eastern Tethys domain, the Capitanian overlaps the regional Murgabian stage, the Midian stage and the lower part of the Laibinian stage. In Russia the Capitanian equals the lower part of the regional Severodvinian stage.

Biostratigraphy

The Capitanian contains one ammonite biozone (Timorites) and three conodont biozones:

* zone of Clarkina postbitteri hongshuiensis
* zone of Jinogondolella altudaensis
* zone of Jinogondolella postserrata

Larger fusulinid species permit a division in two biozones:

* zone of Rausserella
* zone of Afganella schenki

Events

Carbon isotopes in marine limestone from of Capitanian age show an increase in δ13C values. The change in carbon isotopes in the sea water reflects cooling of global climates.[4]

This climatic cooling may have caused the end-Capitanian extinction event among species that lived in warm water, like larger fusulinids (Verbeekninidae), large bivalves (Alatoconchidae and Rugosa corals, and Waagenophyllidae.

References

Notes

1. ^ See Gradstein et al. (2004) for a detailed geologic timescale
2. ^ Glenister & Furnish (1961)
3. ^ The current ICS' subdivision of the Guadalupian epoch/series was first proposed by Glenister et al. (1999)
4. ^ Isozaki et al. (2007)

Literature

* Glenister, B.F. & Furnish, W.M.; 1961: The Permian ammonoids of Australia, Journal of Paleontology 35(4), pp 673-736.
* 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.
* Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press
* Isozaki, Y.; Kawahata, H. & Minoshima, K.; 2007: The Capitanian (Permian) Kamura cooling event: The beginning of the Paleozoic–Mesozoic transition, Palaeoworld 16, p. 16-30.

External links

* GeoWhen Database - Capitanian
* Upper Paleozoic stratigraphic chart at the website of the subcommission for stratigraphic information of the ICS