- Usage in publication:
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- Elephant Head Quartz Monzonite*
- Modifications:
-
- Named
- Geochronologic dating
- Dominant lithology:
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- Quartz monzonite
- AAPG geologic province:
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- Basin-and-Range province
Summary:
Named for Elephant Head in the Santa Rita Mountains, Pima and Santa Cruz Cos, AZ, in Mount Wrightson quad. Elephant Knob is the type area. Is in two stocks in west-central Santa Rita Mountains. A coarse-grained quartz monzonite. Two K-Ar dates on biotite are 68.2 +/-2.4 Ma and 69.0 +/-2.1 Ma. A Pb-alpha date on Zr is 188 Ma. This anomaly may suggest that the unit was initially the Squaw Gulch Granite of Jurassic age and was completely recrystallized during the Late Cretaceous. Is assigned a Late Cretaceous age.
[NOTE: The Department of the Interior's Secretarial Order 3404, issued on November 19, 2021, formally identifies the term “squaw” as derogatory. That Order will create a federal Derogatory Geographic Names Task Force, to find replacement names for geographic features in use by federal agencies. We’re awaiting guidance from the Task Force, and will then take the appropriate actions.]
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 ([ ]).