Gelasian

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Gelasian
2.58 – 1.80 Ma
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Chronology
Formerly part of Tertiary Period/System
Pliocene Epoch/Series
Etymology
Name formalityFormal
Usage information
Celestial body Earth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unit Age
Stratigraphic unit Stage
Time span formalityFormal
Lower boundary definition
Lower boundary GSSPMonte San Nicola Section, Gela, Sicily, Italy
37°08′49″N14°12′13″E / 37.1469°N 14.2035°E / 37.1469; 14.2035
Lower GSSP ratified1996 (as base of Gelasian) [3]
Upper boundary definitionApproximately 8 m after the end of magnetic polarity chronozone C2n (Olduvai).
Upper boundary GSSPVrica Section, Calabria, Italy
39°02′19″N17°08′05″E / 39.0385°N 17.1348°E / 39.0385; 17.1348
Upper GSSP ratified5 December 2011 (as base of Calabrian) [4]

The Gelasian is an age in the international geologic timescale or a stage in chronostratigraphy, being the earliest or lowest subdivision of the Quaternary Period/System and Pleistocene Epoch/Series. It spans the time between 2.58 Ma (million years ago) and 1.80 Ma. [5] It follows the Piacenzian Stage (part of the Pliocene) and is followed by the Calabrian Stage.

Contents

Definition

The Gelasian was introduced in the geologic timescale in 1998. [6] It is named after the Sicilian city of Gela in the south of the island. In 2009 it was moved from the Pliocene to the Pleistocene so that the geologic time scale would be more consistent with the key changes in Earth's climate, oceans, and biota that occurred 2.58 million years ago. [7]

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 occur: Discoaster pentaradiatus and Discoaster surculus. [8] [6] The GSSP 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 [9] [6]

Climate

During the Gelasian the ice sheets in the Northern Hemisphere began to grow, which is seen as the beginning of the Quaternary ice age. Deep sea core samples have identified approximately 40 marine isotope stages (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, this age is now called Biber. It corresponds to Pre-Tegelen and Tegelen in Northern Europe. [10]

During the Gelasian, the Red Crag Formation of Butley, the Newbourn Crag, the Norwich Crag Formation and the Weybourne Crag Formation (all from East Anglia, England) were deposited. The Gelasian is an equivalent of the Praetiglian and Tiglian Stages as defined in the Netherlands, which are commonly used in northwestern Europe.

Related Research Articles

<span class="mw-page-title-main">Neogene</span> Second geologic period in the Cenozoic Era 23–2.6 million years ago

The Neogene is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago (Mya) to the beginning of the present Quaternary Period 2.58 million years ago. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868).

<span class="mw-page-title-main">Pleistocene</span> First epoch of the Quaternary Period

The Pleistocene is the geological epoch that lasted from c. 2.58 million to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek πλεῖστος (pleîstos), meaning "most", and καινός, meaning "new".

<span class="mw-page-title-main">Quaternary</span> Third and current period of the Cenozoic Era, from 2.58 million years ago to the present

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 ago to the present. As of 2023, the Quaternary Period is divided into two epochs: the Pleistocene and the Holocene ; a third epoch, the Anthropocene, has recently been proposed, but it is not officially recognised by the ICS.

The International Commission on Stratigraphy (ICS), sometimes unofficially referred to as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphical, geological, and geochronological matters on a global scale.

<span class="mw-page-title-main">Zanclean</span> Earliest age on the geologic time scale of the Pliocene era

The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 Ma and 3.6 ± 0.005 Ma. It is preceded by the Messinian Age of the Miocene Epoch, and followed by the Piacenzian Age.

The Piacenzian is in the international geologic time scale the upper stage or latest age of the Pliocene. It spans the time between 3.6 ± 0.005 Ma and 2.588 ± 0.005 Ma. The Piacenzian is after the Zanclean and is followed by the Gelasian.

The Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.333 ± 0.005 Ma. It follows the Tortonian and is followed by the Zanclean, the first age of the Pliocene.

Calabrian is a subdivision of the Pleistocene Epoch of the geologic time scale, defined as 1.8 Ma—774,000 years ago ± 5,000 years, a period of ~1.026 million years.

The Serravallian is, in the geologic timescale, an age or a stage in the middle Miocene Epoch/Series, which spans the time between 13.82 Ma and 11.63 Ma. The Serravallian follows the Langhian and is followed by the Tortonian.

The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma. It follows the Serravallian and is followed by the Messinian.

The Thanetian is, in the ICS Geologic timescale, the latest age or uppermost stratigraphic stage of the Paleocene Epoch or Series. It spans the time between 59.2 and56 Ma. The Thanetian is preceded by the Selandian Age and followed by the Ypresian Age. The Thanetian is sometimes referred to as the Late Paleocene.

The Priabonian is, in the ICS's geologic timescale, the latest age or the upper stage of the Eocene Epoch or Series. It spans the time between 37.71 and33.9 Ma. The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage of the Oligocene.

The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/Series. It spans the time between 33.9 and27.82 Ma. It is preceded by the Priabonian Stage and is followed by the Chattian Stage.

The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/Series. It spans the time between 27.82 and23.03 Ma. The Chattian is preceded by the Rupelian and is followed by the Aquitanian.

The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya and 83.6 ± 0.7 mya. The Santonian is preceded by the Coniacian and is followed by the Campanian.

The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma. The Hettangian follows the Rhaetian and is followed by the Sinemurian.

<span class="mw-page-title-main">Sinemurian</span> Second age of the Early Jurassic

In the geologic timescale, the Sinemurian is an age and stage in the Early or Lower Jurassic Epoch or Series. It spans the time between 199.5 ±0.3 Ma and 192.9 ±0.3 Ma. The Sinemurian is preceded by the Hettangian and is followed by the Pliensbachian.

The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 192.9 ±0.3 Ma and 184.2 ±0.3 Ma. The Pliensbachian is preceded by the Sinemurian and followed by the Toarcian.

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 . According to the International Commission on Stratigraphy, the term "chronozone" refers to the rocks formed during a particular time period, while "chron" refers to that time period.

References

Notes

  1. ↑ Cohen, K. M.; Finney, S. C.; Gibbard, P. L.; Fan, J.-X. (January 2020). "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. Retrieved 23 February 2020.
  2. ↑ Mike Walker; et al. (December 2018). "Formal ratification of the subdivision of the Holocene Series/Epoch (Quaternary System/Period)" (PDF). Episodes. Subcommission on Quaternary Stratigraphy (SQS). 41 (4): 213–223. doi:10.18814/epiiugs/2018/018016 . Retrieved 11 November 2019.
  3. ↑ Rio, Domenico; R. Sprovieri; D. Castradori; E. Di Stefano (1998). "The Gelasian Stage (Upper Pliocene): A new unit of the global standard chronostratigraphic scale". Episodes. 21 (2): 82–87. doi: 10.18814/epiiugs/1998/v21i2/002 .
  4. ↑ Cita, Maria; Gibbard, Philip; Head, Martin (September 2012). "Formal ratification of the GSSP for the base of the Calabrian Stage (second stage of the Pleistocene Series, Quaternary System)". Episodes. 35 (3): 388–397. doi: 10.18814/epiiugs/2012/v35i3/001 . hdl: 10261/250367 . Retrieved 26 December 2020.
  5. ↑ "Stratigraphic Chart 2022" (PDF). International Stratigraphic Commission. February 2022. Retrieved 4 June 2022.
  6. 1 2 3 Rio, D., Sprovieri, R., Castradori, D., Di Stefano, E. "The Gelasian Stage (Upper Pliocene): A new unit of the global standard chronostratigraphic scale", Episodes , Vol. 21, No. 1, March 1998. pp 82-87. Retrieved March 18, 2020.
  7. ↑ Gibbard, Philip L.; Head, Martin J.; Walker, Michael J. C. (2009), "Formal ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma", Journal of Quaternary Science, 25 (2): 96, doi: 10.1002/jqs.1338
  8. ↑ Gradstein et al. (2005), p. 28
  9. ↑ Gradstein et al. (2005)
  10. ↑ German Stratigraphic Commission: Stratigraphische Tabelle von Deutschland 2016

Literature

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