Bartonian

Not to be confused with the Bortonian of the New Zealand geologic time scale.

Bartonian
41.2 – 37.71 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Chronology
−65 — – −60 — – −55 — – −50 — – −45 — – −40 — – −35 — – −30 — – −25 — – M Z C e n o z o i c K P a l e o g e n e N L K P a l e o c e n e E o c e n e O l i g o c e n e M C Maastricht. Danian Selandian Thanetian Ypresian Lutetian Bartonian Priabonian Rupelian Chattian Aquitanian         ← PETM ← First Antarctic permanent ice-sheets[1] ← K-Pg mass extinction Subdivision of the Paleogene according to the ICS, as of 2021.[2] Vertical axis scale: millions of years ago
Formerly part of	Tertiary Period/System
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	Not formally defined
Lower boundary definition candidates	Calcareous nannofossil near LAD of the Haptophyte Reticulofenestra reticulata
Lower boundary GSSP candidate section(s)	Contessa highway section, Gubbio, Central Apennines, Italy
Upper boundary definition	LAD of the large acarininids and the Foraminiferan Morozovelloides crassatus
Upper boundary GSSP	Alano section, Piave river, Venetian Prealps, Belluno, Italy 45.9141°N 11.9180°E / 45.9141; 11.9180
Upper GSSP ratified	February 2020[3]

The Bartonian is, in the International Commission on Stratigraphy's (ICS) geologic time scale, a stage or age in the middle of the Eocene Epoch or Series. The Bartonian Age spans the time between 41.2 and 37.71 Ma. It is preceded by the Lutetian and is followed by the Priabonian Age.^[4]

Stratigraphic definition

The Bartonian Stage was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1857. The name derives from the Barton Group, a lithostratigraphic unit from the south English Hampshire Basin, which in turn derived its name from the local coastal village Barton-on-Sea (part of New Milton) in southern England.^[5] The distinction between group and stage was made in the second part of the 20th century, when stratigraphers saw the need to distinguish between litho- and chronostratigraphy.^{[citation needed]}

The base of the Bartonian is at the first appearance of the calcareous nanoplankton species Reticulofenestra reticulata. In 2009, an official reference profile (GSSP) for the base of the Bartonian had not yet been established.^{[needs update][citation needed]}

The top of the Bartonian Stage (the base of the Priabonian) is at the first appearance of calcareous nanoplankton species Chiasmolithus oamaruensis (which forms the base of nanoplankton biozone NP18).^{[citation needed]}

The Bartonian Stage overlaps part of the upper Robiacian European Land Mammal Mega Zone (it spans the Mammal Paleogene zone 16^[6]), the upper Uintan and Duchesnean North American Land Mammal Ages, part of the Divisaderan South American Land Mammal Age and is coeval with the Sharamururian Asian Land Mammal Age. ^{[citation needed]}

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

References

Footnotes

1. Zachos, J. C.; Kump, L. R. (2005). "Carbon cycle feedbacks and the initiation of Antarctic glaciation in the earliest Oligocene". Global and Planetary Change. 47 (1): 51–66. Bibcode:2005GPC....47...51Z. doi:10.1016/j.gloplacha.2005.01.001.
2. "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy.
3. Agnini, Claudia; Backman, Jan; Boscolo-Galazzo, Flavia; Condon, Daniel; Fornaciari, Eliana; Galeotti, Simone; Giusberti, Luca; Grandesso, Paolo; Lanci, Luca; Luciani, Valeria; Monechi, Simonetta; Muttoni, Giovanni; Pälike, Heiko; Pampaloni, Maria; Papazzoni, Cesare; Pearson, Paul; Pignatti, Johannes; Silva, Isabella; Raffi, Isabella; Rio, Domenico; Rook, Lorenzo; Sahy, Diana; Spofforth, David; Stefani, Cristina; Wade, Bridget (12 August 2020). "Proposal for the Global Boundary Stratotype Section and Point (GSSP) for the Priabonian Stage (Eocene) at the Alano section (Italy)". Episodes. 44 (2): 151–173. doi:10.18814/epiiugs/2020/020074. hdl:2158/1209925.
4. International Commission on Stratigraphy 2017
5. "Barton Group". British Geological Survey. UKRI. Retrieved 23 November 2023.
6. Alroy, John. "Mammal Paleogene zones". p. The Paleobiology Database. Retrieved 15 July 2009.

Literature

• Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
• Mayer-Eymar, K.; 1857: Tableau synchronique des formations tertiaires d'Europe, 3rd ed., Zürich. (in French)

External links

• GeoWhen Database – Bartonian
• Paleogene 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