In the
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 geoch ...
, the Anisian is the lower
stage or earliest
age of the
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma ...
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, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...
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 branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...
name of the river
Enns. The original
type locality
Type locality may refer to:
* Type locality (biology)
* Type locality (geology)
See also
* Local (disambiguation)
* Locality (disambiguation)
{{disambiguation ...
is at
Großreifling in the
Austrian state
Austria is a federal republic made up of nine states (German: ''Länder''). Since ''Land'' is also the German word for "country", the term ''Bundesländer'' (literally ''federal states'') is often used instead to avoid ambiguity. The Constitutio ...
of
Styria
Styria (german: Steiermark ; Serbo-Croatian and sl, ; hu, Stájerország) is a state (''Bundesland'') in the southeast of Austria. With an area of , Styria is the second largest state of Austria, after Lower Austria. Styria is bordered to ...
.
The base of the Anisian Stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of
conodont
Conodonts ( Greek ''kōnos'', " cone", + ''odont'', " tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, w ...
species ''
Chiosella timorensis
''Chiosella'' is an extinct conodont genus.
The base of the Anisian stage (also the base of the Middle Triassic series and the top of the Olenekian) is sometimes laid at the first appearance of ''Chiosella timorensis'' in the stratigraphic rec ...
'' 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
Deşli Caira in the
Romania
Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, a ...
n
Dobruja
Dobruja or Dobrudja (; bg, Добруджа, Dobrudzha or ''Dobrudža''; ro, Dobrogea, or ; tr, Dobruca) is a historical region in the Balkans that has been divided since the 19th century between the territories of Bulgaria and Romania. I ...
.
[The GSSP was proposed by Grǎdinaru ''et al.'' (2007)]
The top of the Anisian (the base of the Ladinian) is at the first appearance of
ammonite
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttle ...
species ''
Eoprotrachyceras curionii'' and the ammonite
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
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
biozone
In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa, as opposed to a lithostratigraphic unit which is defined by the lithological properties ...
s:
*zone of ''
Nevadites''
*zone of ''
Hungarites''
*zone of ''
Paraceratites
''Paraceratites'' is an extinct genus of ammonite cephalopods in the family Ceratitidae.
Species
* '' Paraceratites gabbi'' † Meek 1877
* '' Paraceratites binodosus'' † Hauer 1850
* '' Paraceratites brembanus'' † Mojsisovics 1882
* '' Para ...
''
*zone of ''
Balatonites balatonicus''
*zone of ''
Kocaelia''
*zone of ''
Acrochordiceras''
References
Notes
Literature
*; 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
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press in the world. It is also the King's Printer.
Cambr ...
.
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