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National Geologic Map Database
Geologic Unit: Napeequa
Map showing publication footprint
  • Usage in publication:
    • Napeequa Schist*
  • Modifications:
    • Named
  • Dominant lithology:
    • Schist
    • Amphibolite
  • AAPG geologic province:
    • Cascades province
Publication:

Tabor, R.W., Booth, D.B., Vance, J.A., and Ford, A.B., 2002, Geologic map of the Sauk River 30' x 60' quadrangle, Washington: U.S. Geological Survey Miscellaneous Investigations Series Map, I-2592, 2 sheets, 67 p., scale 1:100,000 [http://ngmdb.usgs.gov/Prodesc/proddesc_53957.htm]


Summary:

Unit is named the Napeequa Schist for the Napeequa River, WA. Consists of micaceous quartz schist, garnet-mica-quartz-plagioclase schist, hornblende-mica schist, and amphibolite; also includes to the east of the quadrangle, small masses of meta-igneous rocks, as well as marble and ultramafic rocks. Structurally overlies the Chiwaukum Schist; contact with the Marblemount pluton (=Marblemount Meta Quartz Diorite of Misch, 1966) is tectonic (intrusive). Protolith age is pre-Late Triassic; metamorphic age is Late Cretaceous and [early] 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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