Usage:
Chalk Butte Formation of Idaho Group (OR)
Geologic age:
Tertiary
Pliocene, middle
Type section, locality, area and/or origin of name:
In SE/4 sec. 20, T. 20 S., R. 45 E., Mitchell Butte 30- x 60-min quadrangle, Malheur Co., OR (Corcoran and others, 1962).
AAPG geologic province:
Snake River basin
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 ([ ]).