- Usage in publication:
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- Sheep Hole Mountains Granodiorite*
- Modifications:
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- Named
- Dominant lithology:
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- Granodiorite
- AAPG geologic province:
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- Mojave basin
Summary:
Unit is named the Sheep Hole Mountains Granodiorite of the Coxcomb Intrusive Suite (new) for the Sheep Hole Mountains, San Bernardino Co., CA. Is exposed in the northern Sheep Hole Mountains and small parts of the eastern Bullion Mountains as the Sheep Hole Mountains pluton. These rocks were previously called the granodiorite of Green Scorpion mine by Howard and John (1984). Consists of porphyritic, medium- to coarse-grained sphene- and muscovite-bearing biotite granodiorite. Blocky potassium-feldspar phenocrysts 2-10 cm long. Discrete, anhedral quartz 3-15 mm in diameter. Cut by dikes of the Sheep Hole Pass Granite. As mapped, tentatively includes similar but areally separate rocks in the southern Calumet Mountains. Age is Late Cretaceous.
Source: GNU records (USGS DDS-6; Menlo 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 ([ ]).