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Geologic Unit: Barker
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Map showing publication footprint
  • Usage in publication:
    • Barker porphyry*
  • Modifications:
    • Original reference
  • Dominant lithology:
    • Granite
  • AAPG geologic province:
    • Sweetgrass arch
Publication:

Weed, W.H., 1899, Little Belt Mountains folio, Montana: U.S. Geological Survey Geologic Atlas of the United States Folio, GF-56, [9] p., scale 1:250,000


Summary:

Barker porphyry. Granite porphyry, usually gray or pale brown, weathering reddish. Forms Big Baldy Mountain to south of Barker, Little Belt Mountains, central Montana. Age is post-Cretaceous. [Also forms Barker Mountain, in Fort Benton quadrangle. See also USGS Fort Benton folio, no. 55, 1899.]

Source: US geologic names lexicon (USGS Bull. 896, p. 112).


Map showing publication footprint
  • Usage in publication:
    • Barker porphyry
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Sweetgrass arch
Publication:

Armstrong, F.C., 1957, Eastern and central Montana as a possible source area of uranium: Economic Geology, v. 52, no. 3, p. 211-224.


Summary:

Pg. 221. Barker porphyry. Mentioned in report of Montana as a source area of uranium. Locally Flathead quartzite has been intruded by post-Cretaceous Wolf and Barker porphyries.

Source: US geologic names lexicon (USGS Bull. 1200, p. 214).


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 ([ ]).

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