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 ...
in the international
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 ...
or a
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 ...
in
chronostratigraphy
Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time.
The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geologica ...
, being the earliest or lowest subdivision of the
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
Period/System and
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
Epoch/Series. It spans the time between 2.58 Ma (million years ago) and 1.80 Ma. It follows the
Piacenzian
The Piacenzian is in the international geologic time scale the upper stage (stratigraphy), stage or latest age (geology), age of the Pliocene. It spans the time between 3.6 ± 0.005 year#SI prefix multipliers, Ma and 2.588 ± 0.005 Ma (million yea ...
Stage (part of the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Calabrian Stage.
Episodes
Episodes may refer to:
* Episode
An episode is a narrative unit within a larger dramatic work or documentary production, such as a series intended for radio, television or streaming consumption.
The noun ''episode'' is derived from the Gree ...
'', Vol. 21, No. 1, March 1998. pp 82-87. Retrieved March 18, 2020. It is named after the Sicilian city of
Gela
Gela (Sicilian and ; grc, Γέλα) is a city and (municipality) in the Autonomous Region of Sicily, Italy; in terms of area and population, it is the largest municipality on the southern coast of Sicily. Gela is part of the Province of Cal ...
in the south of the island. In 2009 it was moved from the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
so that the
geologic time scale
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 geochrono ...
would be more consistent with the key changes in Earth's climate, oceans, and biota that occurred 2.58 million years ago.
The base of the Gelasian is defined magnetostratigraphically as the base of the Matuyama (C2r)
chronozone
A chronozone or chron is a unit in chronostratigraphy, defined by events such as
geomagnetic reversals (magnetozones), or based on the presence of specific fossils (biozone or biochronozone).
According to the International Commission on Stratig ...
GSSP
A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted b ...
for the Gelasian is located at the Monte Sant Nicola near Gela.
The top of the Gelasian is defined magnetostratigraphically as the end of the Olduvai (C2n) chronozone, and faunally as the extinction level of the calcareous nanofossil ''Discoaster brouweri'' (base of
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 ...
CN13). Above the Gelasian as the first occurrences of the calcareous nanofossil '' Gephyrocapsa sp.'' and the extinction level of the planktonic
foraminifer
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an ...
''Globigerinoides extremus''
Climate
During the Gelasian the ice sheets in the
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...
began to grow, which is seen as the beginning of the
Quaternary ice age
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
. Deep sea core samples have identified approximately 40
marine isotope stage
Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data reflecting changes in temperature derived from data ...
s (MIS 103 – MIS 64) during the age. Thus, there have probably been about 20 glacial cycles of varying intensity during the Gelasian.
Europe
In the regional glacial history of the
Alps
The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...
Pre-Tegelen
The Tiglian, also referred to as the Tegelen, is a temperate complex stage in the glacial history of Northern Europe. It is preceded by the Praetiglian (stage). The stage was introduced by Zagwijn in 1957 based on geological formations in Tegelen i ...
and
Tegelen
Tegelen ( li, Tegele) is a village in the municipality of Venlo, situated in the Netherlands. It was an independent municipality until 2001, when it was merged into the municipality of Venlo.
Tiglian
The name of the glacial stage of Tiglian (pa ...
Red Crag Formation
The Red Crag Formation is a geological formation in England. It outcrops in south-eastern Suffolk and north-eastern Essex. The name derives from its iron-stained reddish colour and ''crag'' which is an East Anglian word for shells. It is part of th ...
Norwich Crag Formation
The Norwich Crag Formation is a stratigraphic unit of the British Pleistocene Epoch. It is the second youngest unit of the Crag Group, a sequence of four geological formations spanning the Pliocene to Lower Pleistocene transition in East Anglia. ...
East Anglia
East Anglia is an area in the East of England, often defined as including the counties of Norfolk, Suffolk and Cambridgeshire. The name derives from the Anglo-Saxon kingdom of the East Angles, a people whose name originated in Anglia, in ...
, England) were deposited. The Gelasian is an equivalent of the
Praetiglian
The Tiglian, also referred to as the Tegelen, is a temperate complex stage in the glacial history of Northern Europe. It is preceded by the Praetiglian (stage). The stage was introduced by Zagwijn in 1957 based on geological formations in Tegelen i ...
and
Tiglian
The Tiglian, also referred to as the Tegelen, is a temperate complex stage in the glacial history of Northern Europe. It is preceded by the Praetiglian (stage). The stage was introduced by Zagwijn in 1957 based on geological formations in Tegelen i ...
Stages as defined in the
Netherlands
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