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 geochrono ...

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 ...

or stage of the late

Miocene The Miocene ( ) is the first 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 means "less recen ...

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 List of time periods, age or a stage (stratigraphy), stage in the middle Miocene epoch (geology), Epoch/series (stratigraphy), Series, which spans the time between 13.82 annum, Ma and 11.63 Ma (m ...

and is followed by the

Messinian 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 (million years ago). It follows the Tortonian and is followed by the Zanclean, the first ...

. The Tortonian roughly overlaps with the regional Pannonian Stage of the

Paratethys The Paratethys sea, Paratethys ocean, Paratethys realm or just Paratethys was a large shallow inland sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia. Paratethys was peculiar due to its pa ...

timescale of Central Europe. It also overlaps the upper Astaracian,

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 e ...

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 Tortoni ...

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 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 ...

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 ref ...

s and the upper Chasicoan 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 and precedes the Montehermosan age. ...

South American land mammal ages.

Definition

The Tortonian was introduced by Swiss

stratigrapher Stratigraphy is a branch of geology concerned with the study of rock layers ( strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrat ...

Karl Mayer-Eymar Karl David Wilhelm Mayer-Eymar (29 July 1826 – 25 February 1907) was a Franco-Swiss paleontologist and geologist known for his work on classifying the stratigraphy of the Tertiary into 12 stages. He was born Karl Mayer but added the anagram 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 '' Discoaster kugleri'' and planktonic foram '' Globigerinoides subquadratus''. It is also associated with the short normal polarized magnetic chronozone C5r.2n. A GSSP 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 S ...

(Italy). The top of the Tortonian (the base of the

) 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 A supervolcano is a volcano that has had an eruption with a Volcanic Explosivity Index (VEI) of 8, the largest recorded value on the index. This means the volume of deposits for such an eruption is greater than 1,000 cubic kilometers (240 cubic ...

eruptions 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 Ri ...

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