- Usage in publication:
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- Eshe porphyry
- Modifications:
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- Named
- Dominant lithology:
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- Porphyry
- AAPG geologic province:
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- South Park basin
Summary:
Named for prominent exposures around Eshe Ranch, sec 33, T8S, R76W, Park Co, CO in South Park basin. No type locality designated. Forms a series of ridges and hills in South Park underlain by stocks, dikes, and sill-like sheets of quartz monzonite porphyry and quartz diorite porphyry. Is predominantly light gray but has some darker facies. Groundmass varies from aphanitic to medium finely granular. Phenocrysts, in order of abundance, are orthoclase, plagioclase, biotite, quartz, and hornblende. Weathers a buff color. may have come from Princeton batholith. Associated with Baker Lake porphyry. Of Laramide, Paleocene or Late Cretaceous? age. Geologic map.
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 ([ ]).