The Kasimovian is a
geochronologic age
Age or AGE may refer to:
Time and its effects
* Age, the amount of time someone has been alive or something has existed
** East Asian age reckoning, an Asian system of marking age starting at 1
* Ageing or aging, the process of becoming older
...
or
chronostratigraphic stage in the
ICS geologic timescale
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochron ...
. It is the third stage in the
Pennsylvanian (late
Carboniferous
The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...
), lasting from to
Ma.
[; 2004: ''A Geologic Time Scale 2004'', ]Cambridge University
The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...
Press.
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
The Carboniferous rainforest collapse (CRC) was a minor extinction event that occurred around 305 million years ago in the Carboniferous period. The event occurred at the end of the Moscovian and continued into the early Kasimovian stages of th ...
.
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
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
n 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 to ''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
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
''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:
*''
Idiognathodus toretzianus'' Zone
*''Idiognathodus sagittatus'' Zone
*''Streptognathodus excelsus'' and ''Streptognathodus makhlinae'' Zone
References
Literature
*; 1947: ''Geology and Mineral Resources of Moscow and its Surroundings'', Izdat. Moskov. Obshch. Isp. Prir., Moscow, 308 pp. .
*; 2006: ''Global time scale and regional stratigraphic reference scales of Central and West Europe, East Europe, Tethys, South China, and North America as used in the Devonian–Carboniferous–Permian Correlation Chart 2003 (DCP 2003)'', Palaeogeography, Palaeoclimatology, Palaeoecology 240(1-2): pp 318–372.
*
External links
Carboniferous timescaleat the website of the Norwegian network of offshore records of geology and stratigraphy
{{Geological history, p, p, state=collapsed
Pennsylvanian geochronology
Geological ages