- Usage in publication:
-
- Inyo Creek Formation*
- Modifications:
-
- Named
- Dominant lithology:
-
- Quartzite
- AAPG geologic province:
-
- Northern Rocky Mountain region
Summary:
Named as a formation in Lemhi Group (rank raised) for Inyo Creek, Patterson quad, Lemhi Co, ID in Northern Rocky Mountain region. Type area is at head of Inyo Creek, T14N, R24E. Composed of light-greenish-gray, and medium- to dark-gray, very fine grained to fine-grained, feldspathic quartzite. Some beds are silicified and hard, thin bedded, finely cross laminated, and ripple marked. About 700+ ft thick at type. Lower contact concealed; upper contact gradational with overlying West Fork Formation (new). Mapped only in type area and in exposures along North and West Forks of Big Creek tentatively. Correlates with lower part of Ravalli Group of Belt Supergroup. Assigned to Precambrian Y.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Inyo Creek Formation*
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Idaho Mountains province
Summary:
Age of the Inyo Creek Formation of the Lemhi Group is revised from Precambrian Y to Proterozoic Y.
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 ([ ]).