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
...
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 geochron ...
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 geological ...
, 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), as well as the current and most recent of the twelve periods of the ...
Period/System and
Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
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 2.58 Ma (million years ago). T ...
Stage (part of the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Calabrian Stage.
Episodes
Episodes may refer to:
* Episode, a part of a dramatic work
* Episodes (TV series), ''Episodes'' (TV series), a British/American television sitcom which premiered in 2011
* Episodes (journal), ''Episodes'' (journal), a geological science journal
...
'', Vol. 21, No. 1, March 1998. pp 82-87. Retrieved March 18, 2020. It is named after the Sicilian city of Gela in the south of the island. In 2009 it was moved from the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
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 geochro ...
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 (at the Gauss-Matuyama magnetostratigraphic boundary), isotopic stage 103. Above this line notable extinctions of the
calcareous nannofossils
Calcareous nannofossils are a class of tiny (less than 30 microns in diameter) microfossils that are similar to coccoliths deposited by the modern-day coccolithophores. The nannofossils are a convenient source of geochronological data due to ...
GSSP
A Global Boundary Stratotype Section and Point (GSSP), sometimes referred to as a golden spike, is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. ...
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 nannofossil ''Discoaster brouweri'' (base of biozone CN13). Above the Gelasian as the first occurrences of the calcareous nanofossil '' Gephyrocapsa sp.'' and the extinction level of the planktonic foraminifer ''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 by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...
began to grow, which is seen as the beginning of the Quaternary ice age. 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 ratio cycle, oxygen isotope data derived from deep sea core ...
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 () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia.
...
East Anglia
East Anglia is an area of the East of England, often defined as including the counties of Norfolk, Suffolk and Cambridgeshire, with parts of Essex sometimes also included.
The name derives from the Anglo-Saxon kingdom of the East Angles, ...
, England) were deposited. The Gelasian is an equivalent of the Praetiglian and Tiglian Stages as defined in the
Netherlands
, Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...