- Usage in publication:
-
- Copper Creek Granodiorite*
- Modifications:
-
- Named
- Geochronologic dating
- Dominant lithology:
-
- Granodiorite
- AAPG geologic province:
-
- Basin-and-Range province
Summary:
Named for exposures in the lower part of Copper Creek, southwest corner Klondyke quad, Ts7 and 8S, R18E, Pinal Co, AZ in the Basin-and-Range province. Crops out over an area of about 2 sq mi in quad. Extends more than 3 mi farther south into Galiuro Mountains quad. No type locality designated. Forms slopes and smoothly rounded hills and ridges. Is a medium-grained greenish-gray to pale red granodiorite. Varies in mineralogical composition and appearance from place to place. Is porphyritic. Is composed of plagioclase feldspar, quartz, potassium feldspar, and biotite. Detailed petrographic description. Intrudes Precambrian?, Paleozoic, and Mesozoic rocks. Is unconformably overlain by Galiuro Volcanics. Of Late Cretaceous and early Tertiary age. K-Ar age on biotite yielded age of 68 m.y. Geologic map.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Copper Creek Granodiorite*
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Basin-and-Range province
Summary:
Considered to be Late Cretaceous in age in this report, Pinal Co, AZ in the Basin-and-Range province, on basis of 68 m.y. K-Ar age reported earlier by Simons (1964).
Source: GNU records (USGS DDS-6; Denver GNULEX).
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 ([ ]).