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Geologic Units: Fan Lake
Map showing publication footprint
  • Usage in publication:
    • Fan Lake Granodiorite*
  • Modifications:
    • Named
    • Geochronologic dating
  • Dominant lithology:
    • Granodiorite
  • AAPG geologic province:
    • Okanogan province
Publication:

Miller, F.K., 1974, Preliminary geologic map of the Newport Number 3 quadrangle, Pend Oreille, Stevens, and Spokane Counties, Washington: Washington Division of Geology and Earth Resources Geologic Map, GM-9, 1 sheet, 7 p., scale 1:62,500


Summary:

Named for exposures around Fan Lake, especially those south of lake. [Lake is in NW/4 sec.32 T30N R43E, Fan Lake 7.5' quad, Pend Oreille Co, WA. No type locality designated.] Is coarse-grained, mafic hornblende-biotite granodiorite with hornblende crystals as much as a cm long. [No age relations with adjacent rocks given.] K-Ar ages are 95.1 +/-4.0 Ma and 93.4 +/-2.6 Ma on hornblende and biotite, respectively. Assigned Cretaceous 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 ([ ]).

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