Usage:
Halls Diorite Porphyry (OR)
Geologic age:
Miocene
Type section, locality, area and/or origin of name:
Exposed in a roughly rectangular area of about 1 sq mi in North Santiam River gorge; southeastern contact is approx. 1,000 ft east of Halls siding, Marion Co., northwestern OR (Thayer, 1939).
AAPG geologic province:
Western Columbia 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 ([ ]).