- Usage in publication:
-
- Big Pole Formation*
- Modifications:
-
- Named
- Dominant lithology:
-
- Volcaniclastics
- AAPG geologic province:
-
- Great Basin province
Summary:
Named after Big Pole Creek which drains area of most extensive outcrop of formation. Type locality designated as Pony Trail Canyon where only upper 700 ft are exposed. Is lower formation of three in Pony Trail Group (new). Type section for group designated as Pony Trail Canyon in Frenchie Creek and Pine Valley 15' quads, Eureka Co, NV. Consists of volcanic wackes and subordinate altered flows. Maximum thickness may be 6000 ft. Underlies Sod House Tuff (new) (Pony Trail Group). Cut by Lower Cretaceous(?) plutons. Shown on geologic map of French Creek 15' quad. Assigned Mesozoic age.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Big Pole Formation*
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Great Basin province
Summary:
Frenchie Creek Rhyolite of Pony Trail Group is considered Late Jurassic on basis of 151 +/-3 Ma age on biotite (R.L. Armstrong, written commun., 1972). All three formations in group, Big Pole Formation, Sod House Tuff, and Frenchie Creek Rhyolite, are now considered Jurassic and probably Late(?) Jurassic age.
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 ([ ]).