Usage:
Alta Formation (NV*)
Alta Andesite (NV)
Subunits:
Sutro Tuff Member (NV*).
Geologic age:
late Tertiary (early Miocene)*
Type section, locality, area and/or origin of name:
[Type locality not stated.] Occurs in Silver City district, on eastern slope of Virginia Range, 12 mi north of Carson City. Named from exposures near Alta mine shaft [on Comstock lode], Silver City district, [Virginia City 15-min quadrangle], Storey Co., NV (Gianella, 1936).
AAPG geologic province:
Great Basin province*
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 ([ ]).