Tortonian
Encyclopedia
The Tortonian is in the geologic timescale an age or stage of the late Miocene
that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian
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
, Vallesian
and lower Turolian
European Land Mammal Mega Zones, the upper Clarendonian
and lower Hemphillian
North American Land Mammal Ages
and the upper Chasicoan
and lower Huayquerian
South American Land Mammal Ages.
stratigrapher Karl Mayer-Eymar in 1858. It was named after the Italian
city of Tortona
in the region Piemont.
The base of the Tortonian stage is at the last common appearance of calcareous nannoplankton 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
(Italy).
The top of the Tortonian (the base of the Messinian) is at the first appearance of the planktonic foram species Globorotalia conomiozea and is stratigraphically in the middle of magnetic chronozone C3Br.1r.
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian
Serravallian
The Serravallian is in the geologic timescale an age or a stage in the middle Miocene epoch/series, that spans the time between 13.65 ± 0.05 Ma and 11.608 ± 0.005 Ma...
and is followed by the Messinian
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 5.332 ± 0.005 Ma...
.
The Tortonian roughly overlaps with the regional Pannonian stage of the Paratethys
Paratethys
The Paratethys ocean, Paratethys sea or just Paratethys was a large shallow sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in western Asia. The sea was formed during the Oxfordian epoch as an extension of the rift that formed the Central Atlantic Ocean and...
timescale of Central Europe. It also overlaps the upper Astaracian
Astaracian
The Astaracian age 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 Serravallian ages....
, Vallesian
Vallesian
The Vallesian age is a period of geologic time within the Miocene used more specifically with European Land Mammal Ages. It precedes the Turolian age and follows the Astaracian age. The Turolian overlaps the Tortonian and Messinian ages....
and lower Turolian
Turolian
The Turolian age is a period of geologic time 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 and Messinian ages....
European Land Mammal Mega Zones, the upper Clarendonian
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 , typically set from 13,600,000 to 10,300,000 years BP, a period of . It is usually considered to overlap the Serravallian of the Middle...
and lower Hemphillian
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 , typically set from 10,300,000 to 4,900,000 years BP, a period of . It is usually considered to overlap the Tortonian epoch of the Late...
North American Land Mammal Ages
North American Land Mammal Ages
The North American Mammal Ages establishes a geologic timescale for prehistoric North American fauna beginning 66.5 Ma during the Paleocene and continuing through to the Late Pleistocene...
and the upper Chasicoan
Chasicoan
The Chasicoan age is a period of geologic time within the Miocene epoch of the Neogene used more specifically with South American Land Mammal Ages. It follows the Mayoan and precedes the Huayquerian age....
and lower Huayquerian
Huayquerian
The Huayquerian age is a period of geologic time within the Miocene epoch of the Neogene used more specifically with South American Land Mammal Ages. It follows the Mayoan and precedes the Montehermosan age....
South American Land Mammal Ages.
Definition
The Tortonian was introduced by SwissSwitzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
stratigrapher Karl Mayer-Eymar in 1858. It was named after the Italian
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
city of Tortona
Tortona
Tortona 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 Piemont.
The base of the Tortonian stage is at the last common appearance of calcareous nannoplankton Discoaster kugleri
Discoaster
Discoaster is a genus of fossil haptophytes.- Species :Some species in this genus include:*D. asymmetricus Gartner*D. bellus Bukry and Percival*D. berggrenii Bukry*D. bollii Martini and Bramlette...
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
Ancona is a city and a seaport in the Marche region, in central Italy, with a population of 101,909 . Ancona is the capital of the province of Ancona and of the region....
(Italy).
The top of the Tortonian (the base of the Messinian) is at the first appearance of the planktonic foram species Globorotalia conomiozea and is stratigraphically in the middle of magnetic chronozone C3Br.1r.
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 - Tortonian
- Neogene 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