The National Geologic Map Database is migrating to a new infrastructure. We apologize for any service disruptions during this process.

U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Glen Creek Gabbro-Ultramafic Complex*
  • Modifications:
    • Named
    • Geochronologic dating
  • Dominant lithology:
    • Gabbro
    • Peridotite
  • AAPG geologic province:
    • Klamath Mountains province
Publication:

Irwin, W.P., Wolfe, E.W., Blake, M.C., Jr., and Cunningham, C.G., Jr., 1974, Geologic map of the Pickett Peak quadrangle, Trinity County, California: U.S. Geological Survey Geologic Quadrangle Map, GQ-1111, 1 sheet, scale 1:62,500


Summary:

Named for exposures on Glen Creek, sec.24 T1S R7E near Forest Glen, Pickett Peak 15' quad, Trinity Co, CA. Consists chiefly of medium-grained to pegmatitic gabbro and hornblendite with serpentinized peridotite (peridotite indicated separately on map of quad). Isotopic age on hornblende from gabbro yielded 147 +/-9 Ma. Age given as Jurassic.

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 ([ ]).

Accessibility FOIA Privacy Policies and Notices

USA Gov U.S. Department of the Interior | U.S. Geological Survey
Supported by the National Cooperative Geologic Mapping Program
Page Contact Information: Personnel
Page Last Modified: Thu 21 May 2026 05:27:08 PM MDT