Usage:
Opex Formation (UT*)
Geologic age:
Late Cambrian*
Type section, locality, area and/or origin of name:
Not designated. Named from Opex Mine [in T. 10 S., R. 3 W., Eureka 7.5-min quadrangle], Juab Co., UT (Loughlin, IN Lindgren and Loughlin, 1919).
AAPG geologic province:
Great Basin province*
Wasatch uplift*
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 ([ ]).