- Usage in publication:
-
- Clarkforkian age
- Modifications:
-
- Original reference
- AAPG geologic province:
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- Bighorn basin
Summary:
Pg. 9, pl. 1. Clarkforkian age. Provincial time term, based on the Clark Fork member (and faunal zone) of the Polecat Bench formation, type locality, scarp forming divide between Bighorn and Clark Fork basins and exposures near its base, Park County, Wyoming. Includes the interval between the Tiffanian (Paleocene) and Wasatchian (Eocene) ages. [In upper part of Paleocene; = upper part of PLESIADAPIS faunal zone.] Report defines 18 provincial time terms, based on mammal-bearing units, for the North American continental Tertiary. [For sequence see under Puercan.]
Source: US geologic names lexicon (USGS Bull. 1200, p. 822).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).