The
Danian is the oldest
age or lowermost
stage of the
Paleocene epoch or
series, the
Paleogene period or
system and the
Cenozoic era or
erathem. The beginning of the Danian age (and the end of the precessing
Maastrichtian age) is at the
Cretaceous-Tertiary extinction event 65.5 ± 0.3
Ma (million years ago). The age ended 61.7 ± 0.2 Ma, being followed by the
Selandian age.
Stratigraphic definitions
The Danian was introduced in scientific literature by
German-
Swiss geologist
Pierre Jean Édouard Desor in 1847. It is named after the
Latin name for
Denmark. The
Montian stage from
Belgian stratigraphy (named after the city of
Mons) is now considered a
junior synonym and is no longer in use.
The base of the Danian is defined at the iridium anomaly which characterized the Cretaceous-Paleogene boundary in stratigraphic sections worldwide. A section in El Kef, Tunisia was appointed as a reference profile (GSSP) for this important boundary.
The top of the Danian stage (the base of the Selandian) is close to the boundary between biozones NP4 and NP5 from marine biostratigraphy. It is slighltly after the first appearances of many new species of the calcareous nannoplankton genus Fasciculithus (F. ulii, F. billii, F. janii, F. involutus, F. tympaniformis and F. pileatus) and close to the first appearance of calcareous nannoplankton species Neochiastozygus perfectus.
The Danian stage overlaps the Puercan and Torrejonian North American Land Mammal Ages and the Shanghuan and lowest part of the Nongshanian Asian Land Mammal Ages. It includes the oldest Mammal Paleogene zones, all included in the 1 - 5 group.
Palaeontology
Though the non-avian
dinosaurs were gone, the mammals, and other land animals remained small, none bigger than a large domestic cat. But most of the mammals'
orders already had appeared. Numerous lineages of
modern birds also survived, particularly in the area around
Australia but also elsewhere, e.g.
Scaniornis of the
North Sea region. The oceans remained much the same as the
Late Cretaceous seas, only that there was less life, no marine
reptiles, and other lesser known animals.
References
Notes
Literature
;
1847:
Sur le terrain Danien, nouvel étage de la craie, Bulletin de la Societé Géologique de France, série 2, 3, p. 179-181, ISSN 0037-9409.
;
2004:
A Geologic Time Scale 2004,
Cambridge University Press.
;
2006:
The Global Boundary Stratotype Section and Point for the base of the Danian Stage (Paleocene, Paleogene, "Tertiary", Cenozoic) at El Kef, Tunisia: original definition and revision, Episodes
29(4), p. 263-273, ISSN 0705-3797.
External links
GeoWhen Database - Danian
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
Category:Paleocene
