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 geochronol ...

, the Anisian is the lower

stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Sta ...

or earliest

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

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 and ...

series Series may refer to: People with the name * Caroline Series (born 1951), English mathematician, daughter of George Series * George Series (1920–1995), English physicist Arts, entertainment, and media Music * Series, the ordered sets used in ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

and lasted from million years ago until million years ago. The Anisian Age succeeds the

Olenekian In the geologic timescale, the Olenekian is an age in the Early Triassic epoch; in chronostratigraphy, it is a stage in the Lower Triassic series. It spans the time between Ma and Ma (million years ago). The Olenekian is sometimes divided i ...

Age (part of the

Lower Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a un ...

Epoch) and precedes the

Ladinian The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic). ...

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 Wilhelm Heinrich Waagen (23 June 184124 March 1900) was a German geologist and paleontologist. He was born in Munich and died in Vienna. Overview He received a Doctor of Philosophy degree at the University of Munich, where he studied the rocks and ...

and

Carl Diener Carl Diener (11 December 1862 in Vienna – 6 January 1928, Vienna) was an Austrian geographer, geologist and paleontologist. Biography In 1883 he received his doctorate from the University of Vienna, where his instructors included Eduard ...

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 of the ...

name of the river Enns. The original type locality is at Großreifling in the Austrian state 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, which ...

species '' Chiosella timorensis'' in the stratigraphic record. Other stratigraphers prefer to use the base of

magnetic chronozone Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles ...

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 Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...

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 cuttlefish) ...

species '' Eoprotrachyceras curionii'' and the ammonite

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Trachyceratidae The Trachyceratidae is an extinct family of ceratitid ammonoid cephalopods. The Trachyceratidae makes up part of the superfamily Trachyceratoidea along with such families as the Buchitidae, Distichitidae, Dronovitidae and Noridiscitidae. ...

. 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 of ...

s: *zone of '' Nevadites'' *zone of '' Hungarites'' *zone of '' Paraceratites'' *zone of '' Balatonites balatonicus'' *zone of '' Kocaelia'' *zone of ''

Acrochordiceras ''Acrochordiceras'' is a genus of Middle Triassic ammonoid cephalopods belonging to the ceratitid family Acrochordiceratidae, included in the superfamily Ceratitoidea. The shell of ''Acrochordiceras'', as with the family, is more or less inv ...

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 A university press is an academic publishing hou ...

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