- Usage in publication:
-
- Twin Lakes quartz monzonite porphyry
- Modifications:
-
- Original reference
- Dominant lithology:
-
- Porphyry
- AAPG geologic province:
-
- Eagle basin
Summary:
Twin Lakes quartz monzonite porphyry. A fresh coarse-grained light-gray monzonite carrying large euhedral orthoclase crystals. Found on both sides of valley of Lake Creek below Everett and in vicinity of Twin Lakes, Lake County, central Colorado. ["Probably late Paleozoic" on map and p. 33; "tentatively assigned to Mesozoic and correlated with Mesozoic intrusions elsewhere" on p. 51.]
[Notable exposures in Chaffee and Lake Cos., central CO.]
Source: US geologic names lexicon (USGS Bull. 896, p. 2203).
- Usage in publication:
-
- Twin Lakes porphyry
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Eagle basin
Stark, J.T., and Barnes, F.F., 1935, Geology of the Sawatch Range, Colorado: Colorado Scientific Society Proceedings, v. 13, no. 8, p. 467-479, (incl. geologic map)
Summary:
Map. Twin Lakes porphyry assigned to Tertiary.
Source: US geologic names lexicon (USGS Bull. 896, p. 2203).
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 ([ ]).