Kasimovian
307.0 ± 0.1 – 303.7 ± 0.1 Ma
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Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionNot formally defined
Lower boundary definition candidatesFAD of the Fusulinid Protriticites or 1 million years older Montiparus montiparus[2]
Lower boundary GSSP candidate section(s)
Upper boundary definitionNot formally defined
Upper boundary definition candidatesFAD of the Conodont Idiognathodus simulator[2]
Upper boundary GSSP candidate section(s)
  • Southern Ural mountains[2]
  • Nashui, Luodian County, Guizhou, China

The Kasimovian is a geochronologic age or chronostratigraphic stage in the ICS geologic timescale. It is the third stage in the Pennsylvanian (late Carboniferous), lasting from 307 to 303.7 Ma.[3] The Kasimovian Stage follows the Moscovian and is followed by the Gzhelian. The Kasimovian saw an extinction event which occurred around 305 mya, referred to as the Carboniferous Rainforest Collapse.[4] It roughly corresponds to the Missourian in North American geochronology and the Stephanian in western European geochronology.

Name and definition

The Kasimovian is named after the Russian city of Kasimov. The stage was split from the Moscovian in 1926 by Boris Dan'shin (1891-1941), who gave it the name Teguliferina horizon. The name was posthumously changed in Kasimov horizon by Dan'shin in 1947. The name Kasimovian was introduced by Georgy Teodorovich in 1949.

The base of the Kasimovian Stage is at the base of the fusulinid biozone of Obsoletes obsoletes and Protriticites pseudomontiparus or with the first appearance of the ammonite genus Parashumardites. The top of the stage is close to the first appearances of the fusulinid genera Daixina, Jigulites and Rugosofusulina or the first appearance of the conodont Streptognathodus zethus.

Biozones

The Kasimovian is subdivided into three conodont biozones:

References

  1. ^ "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
  2. ^ a b c d "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 23 December 2020.
  3. ^ Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
  4. ^ Sahney, S., Benton, M.J. & Falcon-Lang, H.J. (2010). "Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica" (PDF). Geology. 38 (12): 1079–1082. Bibcode:2010Geo....38.1079S. doi:10.1130/G31182.1.((cite journal)): CS1 maint: multiple names: authors list (link)

Literature

External links

Geological history of Earth
Categories