Usage:
Picture Gorge Basalt of Columbia River Basalt Group (ID*,OR*,WA*)
(†Picture Gorge basalt subgroup [informal] of Columbia River Basalt Group (OR-local) discarded by the OR Geol. Survey and the USGS.)
[Columbia River Basalt Group adopted by the ID, OR, and WA Geol. Surveys, and the USGS (rules suspended).]
Geologic age:
late Tertiary (early Miocene)*
Type section, locality, area and/or origin of name:
Type section: roadcuts along U.S. Highway 26 near junction with State Highway 19, in SW/4 sec. 17, NE/4 sec. 18, and NW/4 sec. 20, T. 12 S., R. 26 [E.], Picture Gorge, [John Day Fossil Beds National Monument, Picture Gorge West 7.5-min quadrangle], Grant Co., north-central OR (Waters, 1961; Swanson and others, 1979).
Reference localities (Swanson and others, 1979): (1) on Monument Mountain, in S/2 sec. 19, T. 8 S., R. 28 E., Monument quadrangle; and (2) along Holmes Creek Road, in secs. 4, 5, and 9, T. 10 S., R. 26 E., Picture Gorge quadrangle.
Reference locality (†Picture Gorge basalt subgroup): Monument Mountain, in sec. 19, T. 8 S., R. 26 E., OR; Holmes Creek, in secs. 4, 5, and 9, T. 10 S., R. 25 E., OR (Bailey, 1989).
AAPG geologic province:
Blue Mountains province*
Eastern Columbia basin*
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 ([ ]).