The Bartonian is, in the ICS's

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 ...

, a stage or age in the middle

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

Epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided ...

or Series. The Bartonian Age spans the time between . It is preceded by the

Lutetian The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the ...

and is followed by the

Priabonian 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 . The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage ...

Age.International Commission on Stratigraphy 2017
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Stratigraphic definition

The Bartonian Stage was introduced by

Swiss Swiss may refer to: * the adjectival form of Switzerland *Swiss people Places * Swiss, Missouri *Swiss, North Carolina * Swiss, West Virginia *Swiss, Wisconsin Other uses * Swiss-system tournament, in various games and sports * Swiss Internation ...

stratigrapher

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 1857. The name derives from the coastal village Barton-on-Sea (part of

New Milton New Milton is a market town in southwest Hampshire, England. To the north is in the New Forest and to the south the coast at Barton-on-Sea. The town is equidistant between Lymington and Christchurch, 6 miles (10 km) away. History ...

) in southern England. The Barton Group, a

lithostratigraphic Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology. In general, strata are primarily igneou ...

unit from the south English Hampshire Basin, is of Bartonian age. The distinction between

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic ide ...

and stage was made in the second part of the 20th century, when stratigraphers saw the need to distinguish between litho- and

chronostratigraphy Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time. The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geologic ...

. The base of the Bartonian is at the first appearance of the 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 ...

species ''Reticulofenestra reticulata''. In 2009, an official reference profile ( GSSP) for the base of the Bartonian had not yet been established. The top of the Bartonian Stage (the base of the Priabonian) is at the first appearance of calcareous

species ''Chiasmolithus oamaruensis'' (which forms the base of nanoplankton biozone NP18). The Bartonian Stage overlaps part of the upper Robiacian European Land Mammal Mega Zone (it spans the Mammal Paleogene zone 16), the upper Uintan and Duchesnean

North American Land Mammal Ages 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 ...

, part of the Divisaderan South American Land Mammal Age and is coeval with the Sharamururian

Asian Land Mammal Age The Asian land mammal ages, acronym ALMA, establish a geologic timescale for prehistoric Asian fauna beginning 58.7 Mya during the Paleogene and continuing through to the Miocene ( Aquitanian) (23.03 Ma). These periods are referred to as ages, sta ...

. The Auversian regional stage of France is coeval with the Bartonian and is therefore no longer used.

References

Footnotes

Literature

*; 2004: ''A Geologic Time Scale 2004'',

Cambridge University Press Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by King Henry VIII in 1534, it is the oldest university press in the world. It is also the King's Printer. Cambridge University Pr ...

. *; 1857: ''Tableau synchronique des formations tertiaires d'Europe'', 3rd ed., Zürich.

External links

GeoWhen Database – BartonianPaleogene timescale
at the website of the subcommission for stratigraphic information of the ICS
Stratigraphic chart of the Paleogene
at the website of Norges Network of offshore records of geology and stratigraphy {{Geological history, p, c Eocene geochronology Geological ages