- Usage in publication:
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- Granite Basin Porphyry*
- Modifications:
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- Named
- Dominant lithology:
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- Porphyry
- AAPG geologic province:
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- Basin-and-Range province
Summary:
Named for good exposures at its type locality in Granite Basin, Christmas 15' quad, Gila Co, AZ, Basin-and-Range province. Crops out over about 16 sq km about 35 km south-southeast of Globe, AZ. These rocks mapped previously as part of an unnamed part of a feldspar-mica-porphyry unit by Wilden (1964). Is a sill-like mass of porphyry occurring in Escabrosa and Naco Limestones. Dominant characteristics are uniform chemical composition, texture, mineralogy, and evenness in degree and extent of secondary alteration. Detailed description of lithology. Has K-Ar age on hornblende of 72.3 +/-1.6 and 60.7 +/-0.6 m.y., Late Cretaceous and Paleocene.
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 ([ ]).