- Usage in publication:
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- Thompson limestone
- Modifications:
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- First used
- Dominant lithology:
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- Limestone
- AAPG geologic province:
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- Sierra Nevada province
Summary:
Geologic column of Taylorville [Taylorsville] region shows Thompson limestone to be 10 to 30 ft thick and Middle Jurassic in age. Unit is gray in upper part and red and impure in lower part. Lies between Mormon sandstone and Hardgrave sandstone. Fossils identified by Prof. Alpheus Hyatt indicate Middle Jurassic age.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
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- Thompson limestone*
- Modifications:
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- Named
- Dominant lithology:
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- Limestone
- AAPG geologic province:
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- Sierra Nevada province
Summary:
[Named] for exposures on Thompson's ranch on west slope of Mount Jura, east of Taylorsville, Plumas Co, CA. Extends to lower slope of Grizzly Mountains, a mi southeast of Huntington's. At elevation of 4100 ft outcrop has thickness of 40 ft. Is gray and somewhat shaly; on weathered surface in places are round, oblong, or irregular patches of darker more or less granular calcite. Where shaly unit is generally red, highly argillaceous and locally full of long slender gastropods. Overlies Fant meta-andesite; underlies Mormon sandstone; beds are overturned on eastern side so younger Mormon sandstone appears to be below older Thompson limestone.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Thompson Limestone*
- Modifications:
-
- Age modified
- Biostratigraphic dating
- AAPG geologic province:
-
- Sierra Nevada province
Summary:
Thompson Limestone is provisionally assigned Pliensbachian age (Early Jurassic) because gray limestone lentils within unit contain pelecypod, PLICATOSTYLUS.
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 ([ ]).