The Aquitanian is, in the ICS

International Commission on Stratigraphy

The International Commission on Stratigraphy , sometimes referred to by the unofficial "International Stratigraphic Commission" is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphy, geological, and geochronological matters on a global...

' geologic timescale, the oldest age or lowest stage in the Miocene

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...

. It spans the time between 23.03 ± 0.05 Ma and 20.43 ± 0.05 Ma (million years ago) and is a dry, cooling period. The Aquitanian succeeds the Chattian

Chattian

The Chattian is, in the geologic timescale, the youngest of two ages or upper of two stages of the Oligocene epoch/series. It spans the time between and . The Chattian is preceded by the Rupelian and is followed by the Aquitanian .-Stratigraphic definition:The Chattian was introduced by Austrian...

 (the youngest age of the Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

) and precedes the Burdigalian

Burdigalian

The Burdigalian is, in the geologic timescale, an age or stage in the early Miocene. It spans the time between 20.43 ± 0.05 Ma and 15.97 ± 0.05 Ma...

.

The Aquitanian age overlaps with the Harrisonian

Harrisonian

The Harrisonian 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 24,800,000 to 20,600,000 years BP, a period of . It is usually considered to overlap the Chattian and Aquitarian stages...

, Agenian

Agenian

The Agenian age is a period of geologic time within the Miocene used more specifically with European Land Mammal Ages. It follows the Orleanian age and overlaps the Aquitanian and Burdigalian ages....

, Pareora

Pareora

Pareora is a settlement in New Zealand. It is located close to State Highway 1, which bypasses the western edge of the town, and close to the Pacific Ocean coast, five kilometres north of Saint Andrews and 10 kilometres south of Timaru. The Pareora River reaches the ocean just to the south of the...

, Landon

Landon

-Given name:* Alfred Felix Landon Beeston* Charles Landon Knight* James Landon Knight* Landon * Landon Carter* Landon Carter Haynes, Sr.* Landon Cassill* Landon Cohen* Landon Curt Noll* Landon Donovan* Landon Garland* Landon Gilkey...

, Otaian, and Waitakian ages from various regional timescales.

Stratigraphic definition

The Aquitanian stage was named after the region Aquitaine

Aquitaine

Aquitaine , archaic Guyenne/Guienne , is one of the 27 regions of France, in the south-western part of metropolitan France, along the Atlantic Ocean and the Pyrenees mountain range on the border with Spain. It comprises the 5 departments of Dordogne, :Lot et Garonne, :Pyrénées-Atlantiques, Landes...

 in France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 and was introduced in scientific literature by Swiss

Switzerland

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.

The base of the Aquitanian (also the base of the Miocene series

Series (stratigraphy)

Series are subdivisions of rock layers made based on the age of the rock and corresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a...

 and the Neogene

Neogene

The Neogene is a geologic period and system in the International Commission on Stratigraphy Geologic Timescale starting 23.03 ± 0.05 million years ago and ending 2.588 million years ago...

 system) is defined as the place in the stratigraphic column

Stratigraphic column

A stratigraphic column is a representation used in geology and its subfield of stratigraphy to describe the vertical location of rock units in a particular area....

 at the first appearance of foram species Paragloborotalia kugleri, the extinction

Extinction

In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

 of calcareous nannoplankton species Reticulofenestra bisecta (which forms the base of nannoplankton biozone

Biozone

Biostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....

 NN1), and the base of magnetic chronozone C6Cn.2n. The official GSSP for the Aquitanian stage lies in the Lemme-Carrioso section near the small village of Carrioso (north of Genoa

Genoa

Genoa |Ligurian]] Zena ; Latin and, archaically, English Genua) is a city and an important seaport in northern Italy, the capital of the Province of Genoa and of the region of Liguria....

) in northern Italy

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...

.

The top of the Aquitanian stage (the base of the Burdigalian) is at the first appearance of foram species Globigerinoides altiaperturus and the top of magnetic chronozone C6An.

Literature

; 2004: A Geologic Time Scale 2004, Cambridge University Press

Cambridge University Press

Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

.; 1858: Versuch einer neuen Klassifikation der Tertiär-Gebilde Europa’s, Verhandlungen der Schweizerischen Naturforschenden Gesellschaft 17–19 (August 1857), p. 70–71 & 165–199. ; 1997: The Global Stratotype Section and Point (GSSP) for the base of the Neogene, Episodes 20(1), p. 23-28.

External links

• GeoWhen Database - Aquitanian
• 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