Tortonian salinity crisis
   HOME

TheInfoList



OR:

The Tortonian is in 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 geochr ...
an age or
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 ...
of the late
Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the
Serravallian 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 (million years ago). The Serravallian follows the Langhian and is followed by the Tortonian ...
and is followed by the Messinian. The Tortonian roughly overlaps with the regional Pannonian Stage of the Paratethys timescale of Central Europe. It also overlaps the upper
Astaracian The Astaracian age is a period of geologic time (), equivalent with the Middle Miocene and used more specifically with European Land Mammal Ages. It precedes the Vallesian age and follows the Orleanian age. The Astaracian overlaps the Langhian and ...
,
Vallesian The Vallesian age is a period of geologic time (11.6–9.0 Ma) within the Miocene used more specifically with European Land Mammal Ages. It precedes the Turolian age and follows the Astaracian age. The so-called Vallesian Crisis resulted in the ...
and lower
Turolian The Turolian age is a period of geologic time (9.0–5.3 Ma) within the Miocene used more specifically with European Land Mammal Ages. It precedes the Ruscinian age and follows the Vallesian age. The Turolian overlaps the Tortonian The Tort ...
European land mammal age The European Land Mammal Mega Zones (abbreviation: ELMMZ, more commonly known as European land mammal ages or ELMA) are zones in rock layers that have a specific assemblage of fossils (biozones) based on occurrences of fossil assemblages of Europe ...
s, the upper
Clarendonian The Clarendonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 13,600,000 to 10,300,000 years BP, a period of . It is ...
and lower
Hemphillian The Hemphillian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 10,300,000 to 4,900,000 years BP. It is usually considered t ...
North American land mammal age The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when re ...
s and the upper
Chasicoan The Chasicoan ( es, Chasiquense or es, Chasicoense) age is a period of geologic time from 10–9 Ma within the Late Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Mayoan and ...
and lower
Huayquerian The Huayquerian ( es, Huayqueriense) age is a period of geologic time (9.0–6.8 Ma) within the Late Miocene epoch of the Neogene, used more specifically within the SALMA classification. It follows the Mayoan The Mayoan ( es, Mayoense) age is ...
South American land mammal age The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as age ...
s.


Definition

The Tortonian was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1858. It was named after the Italian city of
Tortona Tortona (; pms, Torton-a , ; lat, Dhertona) is a ''comune'' of Piemonte, in the Province of Alessandria, Italy. Tortona is sited on the right bank of the Scrivia between the plain of Marengo and the foothills of the Ligurian Apennines. History ...
in the region
Piedmont it, Piemontese , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = , demographics1_footnotes = , demographics1_title1 = , demographics1_info1 = , demographics1_title2 ...
. The base of the Tortonian Stage is at the last common appearance of calcareous
nanoplankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cruc ...
'' Discoaster kugleri'' and planktonic
foram 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 a ...
'' Globigerinoides subquadratus''. It is also associated with the short normal polarized magnetic chronozone C5r.2n. A
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 ...
for the Tortonian has been established in the Monte dei Corvi section near
Ancona Ancona (, also , ) is a city and a seaport in the Marche region in central Italy, with a population of around 101,997 . Ancona is the capital of the province of Ancona and of the region. The city is located northeast of Rome, on the Adriatic ...
(Italy). The top of the Tortonian (the base of the Messinian) is at the first appearance of the planktonic foram species ''
Globorotalia conomiozea ''Globorotalia'' is a genus of foraminifers belonging to the family Globorotaliidae. It is a single-celled animal large enough to be seen with a naked eye and is found in the fossil record back to the Paleocene. It is deep-dwelling planktonic fo ...
'' and is stratigraphically in the middle of magnetic chronozone C3Br.1r.


Geologic history

In 2020, geologists reported two newly-identified supervolcano
eruptions Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...
associated with the
Yellowstone hotspot The Yellowstone hotspot is a volcanic hotspot in the United States responsible for large scale volcanism in Idaho, Montana, Nevada, Oregon, and Wyoming, formed as the North American tectonic plate moved over it. It formed the eastern Snake Riv ...
track, including the region's largest and most cataclysmic event – the Grey's Landing super-eruption – which had a volume of at least 2,800 km3 and occurred around 8.72 Ma.


References


Notes


Literature

*; 2004: ''A Geologic Time Scale 2004'', Cambridge University Press. *; 2005: ''The Global boundary Stratotype Section and Point (GSSP) of the Tortonian Stage (Upper Miocene) at Monte Dei Corvi'', Episodes 28, p. 6-17. *; 1858: ''Versuch einer neuen Klassifikation der Tertiär-Gebilde Europa’s'', Verhandlungen der Schweizerischen Naturforschenden Gesellschaft, Jahresversammlung 1857, p. 70–71 & 165–199.


External links


GeoWhen Database - TortonianNeogene timescale
at the website of the subcommission for stratigraphic information of the ICS
Neogene timescale
at the website of the Norwegian network of offshore records of geology and stratigraphy {{Geological history of Earth, p, c *05 Miocene geochronology Geological ages