- Usage in publication:
-
- Little Sheep Creek conglomerate unit
- Modifications:
-
- Named
- Dominant lithology:
-
- Conglomerate
- AAPG geologic province:
-
- Montana folded belt
Summary:
An informal unit in Beaverhead Group named for Little Sheep Creek, north of Alder Creek, Beaverhead Co, MT, Montana folded belt province. Known only in Little Sheep Creek area and replaces use of Divide conglomerate unit of Beaverhead in area. Clast composition in Little Sheep Creek differs from that of the Divide. Thickness not determined because of structural imbrication and poor exposure. Consists of highly polished or rounded quartzite clasts derived chiefly from Proterozoic Lemhi Group, and other quartzite clasts from Paleozoic units, such as Ordovician Kinnikinic Quartzite and Ordovician Beaverhead Mountains pluton. Clasts were probably recycled from deeply eroded hinterland thrust sheets now exposed in Beaverhead Mountains and Lemhi Range. Is younger than Lima Conglomerate of Beaverhead and probably 78-69 Ma or Campanian and Maestrichtian, Late Cretaceous. Distribution shown on fig. 2.
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 ([ ]).