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Geologic Unit: Howson
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Map showing publication footprint
  • Usage in publication:
    • Howson andesite*
  • Modifications:
    • Named
  • Dominant lithology:
    • Andesite
  • AAPG geologic province:
    • Cascades province
Publication:

Smith, G.O., and Calkins, F.C., 1906, Description of the Snoqualmie quadrangle, Washington: U.S. Geological Survey Geologic Atlas of the United States Folio, Snoqualmie folio, no. 139, 14 p., scale 1:125,000


Summary:

Unit is named the Howson andesite. [Probably] named for two exposures on Howson Creek, Kittitas Co., WA. Consists of hornblende andesite. Unconformably overlies the Swauk sandstone (new). Age is Pliocene(?) based on stratigraphic relationships.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Howson Andesite*
  • Modifications:
    • Age modified
    • Areal extent
  • AAPG geologic province:
    • Cascades province
Publication:

Tabor, R.W., Frizzell, V.A., Booth, D.B., and Waitt, R.B., 2000, Geologic map of the Snoqualmie Pass 30' x 60' quadrangle, Washington; Version 1.0: U.S. Geological Survey Miscellaneous Investigations Series Map, I-2538, 1 sheet, 57 p., scale 1:100,000 [http://ngmdb.usgs.gov/Prodesc/proddesc_37097.htm]


Summary:

Howson Andesite is geographically extended into the report area. Age is modified from Pliocene(?) to: Miocene.

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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