- Usage in publication:
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- Evolution Basin Alaskite*
- Modifications:
-
- Named
- Geochronologic dating
- Dominant lithology:
-
- Granite
- AAPG geologic province:
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- Sierra Nevada province
Summary:
Named for exposures in Evolution Basin [37 deg 08'08"N, 118 deg 41'44"W, Fresno Co, CA] which are designated type locality. Is youngest unit of John Muir Intrusive Suite (new). Formerly called alaskite of Evolution Basin and LeConte Canyon by Bateman and Moore (1965) and leucogranite of Evolution Basin by Stern and others (1981). It lies between S half of Lamarck Granodiorite on E and Mount Goddard septum on W. Forms elongate body about 20 km by 5 km. Composed of alaskite which is extremely felsic. Intrudes Lamarck Granodiorite. Intruded by granodiorite of Cartridge Pass. K-Ar ages on biotite from 85 to 79 Ma indicate Late Cretaceous age.
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 ([ ]).