- Usage in publication:
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- Basin Gulch Quartzite Member*
- Modifications:
-
- Named
- Dominant lithology:
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- Quartzite
- AAPG geologic province:
-
- Snake River basin
Summary:
Named from exposures just northwest of junction of Basin Gulch and Trail Creek near east edge of Rock Roll Canyon quad, Blaine Co, ID in the Snake River basin which compose the type locality. Is basal member of Phi Kappa Formation (revised). Lower contact is a fault; upper contact gradational with black graptolitic argillite of Phi Kappa Formation. Basin Gulch is 60 m or less of gray, fine-grained, locally pebbly quartzite. Thickness varies due to deformation. Is of limited areal extent. Is Early Ordovician in age. Lowest graptolite occurrence (zones 2-4 of Berry are late Tremadocian-Arenigian) in Phi Kappa is 15 cm above top of Basin Gulch. Geologic map.
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 ([ ]).