Clarkforkian

The Clarkforkian North American Stage, on the geologic timescale, is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 56,800,000 to 55,400,000 years BP lasting 1.4 million years.[1]

Considered to be within the Paleocene, more specifically the Late Paleocene, the Clarkforkian shares its upper boundary with the Thanetian.

The Clarkforkian is preceded by the Tiffanian and followed by the Wasatchian NALMA stages.

Substages

It is considered to contain the following substages:

  • Cf3: (shares the upper boundary) and lower boundary source of the base of Clarkforkian (approximate) and upper boundary source of the base of the Ypresian (approximate).
  • Cf2: Is the lower boundary source of the base of the Clarkforkian (approximate)
  • Cf1: Upper boundary source of the base of the Ypresian (approximate)

Fauna

Notable mammals[2][3]

Multituberculata - non-therian mammals

Metatheria - marsupials

Carnivora - carnivores, including living carnivorous mammals

Condylarthra - archaic ungulates

Creodonta - extinct group of carnivorous mammals

Dinocerata - large, tusked herbivores

Eulipotyphla - insectivorous mammals

  • Plagioctenodon, nyctitheriid insectivore
  • Wyonycteris, nyctitheriid insectivore

Mesonychia - carnivorous hoofed mammals

Pantodonta - large herbivorous mammals

Primatomopha - primates and relatives

Rodentia - rodents

Tillodontia - medium sized, digging herbivores

  • Esthonyx, esthonychid tillodont
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References
  1. Paleobiology Database, Clarkforkian
  2. "The Clarkforkian Land-Mammal Age and Mammalian Faunal Composition Across the Paleocene-Eocene Boundary". hdl:2027.42/48626. Cite journal requires |journal= (help)
  3. Wilf, Peter; Beard, K. Christopher; Davies-Vollum, K. Sian; Norejko, Jay W. (December 1998). "Portrait of a Late Paleocene (Early Clarkforkian) Terrestrial Ecosystem: Big Multi Quarry and Associated Strata, Washakie Basin, Southwestern Wyoming". PALAIOS. 13 (6): 514. Bibcode:1998Palai..13..514W. doi:10.2307/3515344. ISSN 0883-1351. JSTOR 3515344.


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