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  • Usage in publication:
    • Chirikof Formation*
  • Modifications:
    • Named
  • Dominant lithology:
    • Conglomerate
    • Sandstone
    • Shale
  • AAPG geologic province:
    • Aleutian Islands province
    • Alaska Southwestern region
Publication:

Gates, Olcott, Powers, H.A., and Wilcox, R.E., 1971, Geology of the Near Islands, Alaska, with a section on the surficial geology of the Near Islands [Attu Island, Agattu Island, and Shemya Island] by J.P. Schafer, IN Investigations of Alaskan volcanoes: U.S. Geological Survey Bulletin, 1028-U, p. U709-U822, (incl. geologic maps, scale 1:63,360)


Summary:

Named for exposures at type locality along south shore of Chirikof Point, east central Attu Island, Near Islands, AK. Composed of conglomerate, sandstone, shale, and lava. Is separated from outcrops of basement rocks by a gravel beach and a sill or dike. Is 60 m thick. Contains fossil leaves CERCIDIPHYLLUM sp. and ALNUS ALNIFOLIA (Goppert) Hollick. Age is middle Tertiary.

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 ([ ]).

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