In the
geologic timescale, the Anisian is the lower
stage or earliest
age of the
Middle Triassic series or
epoch and lasted from million years ago until million years ago.
The Anisian Age succeeds the
Olenekian Age (part of the
Lower Triassic Epoch) and precedes the
Ladinian Age.
Stratigraphic definitions
The stage and its name were established by
Austria
Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...
n geologists
Wilhelm Heinrich Waagen and
Carl Diener in 1895. The name comes from ''Anisus'', the
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
name of the river
Enns. The original
type locality is at
Großreifling in the
Austrian state of
Styria.
The base of the Anisian Stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of
conodont species ''
Chiosella timorensis'' in the stratigraphic record. Other stratigraphers prefer to use the base of
magnetic chronozone MT1n. There is no accepted global reference profile for the base, but one (
GSSP or golden spike) was proposed at a flank of the mountain
Deșli Caira in the
Romania
Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...
n
Dobruja.
[The GSSP was proposed by Grădinaru ''et al.'' (2007)]
The top of the Anisian (the base of the Ladinian) is at the first appearance of
ammonite species ''
Eoprotrachyceras curionii'' and the ammonite
family Trachyceratidae. The conodont species ''
Neogondolella praehungarica'' appears at the same level.
Especially in Central Europe the Anisian Stage is sometimes subdivided into four substages:
Aegean,
Bythinian,
Pelsonian and
Illyrian.
The Anisian contains six ammonite
biozones:
*zone of ''
Nevadites''
*zone of ''
Hungarites''
*zone of ''
Paraceratites''
*zone of ''
Balatonites balatonicus''
*zone of ''
Kocaelia''
*zone of ''
Acrochordiceras''
Selected formations
*
Ashfield Shale (
New South Wales
New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...
, Australia)
* Lower and middle
Besano Formation (Switzerland and Italy)
* Upper
Ermaying Formation (
Shaanxi and
Shanxi
Shanxi; Chinese postal romanization, formerly romanised as Shansi is a Provinces of China, province in North China. Its capital and largest city of the province is Taiyuan, while its next most populated prefecture-level cities are Changzhi a ...
, China)
*
Favret Formation /
Prida Formation (
Fossil Hill Member) (Nevada, US)
*
Grès à Voltzia (France)
*
Guanling Formation (
Guizhou and
Yunnan
Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
, China)
*
Moenkopi Formation (Holbrook and Anton Chico members) (SW US)
* Lower and Middle
Muschelkalk (central Europe)
*
Röt Formation /
Upper Buntsandstein (Germany)
References
Sources
*; 2005: ''The Global boundary Stratotype Section and Point (GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale'', Episodes 28(4), pp. 233–244.
*; 2007: ''The Global Boundary Stratotype Section and Point (GSSP) for the base of the Anisian Stage: Deşli Caira Hill, North Dobrogea, Romania'', Albertiana 36, pp. 54–71.
*; 2004: ''A Geologic Time Scale 2004'',
Cambridge University Press.
External links
GeoWhen Database - AnisianLower Triassic timescale
at the website of the subcommission for stratigraphic information of the ICS
Lower Triassic timescale
at the website of Norges Network of offshore records of geology and stratigraphy.
{{coord, 45.0742, N, 28.8022, E, source:wikidata, display=title
*01
Geological ages
Triassic geochronology