The National Geologic Map Database is migrating to a new infrastructure. We apologize for any service disruptions during this process.

U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Silver Point Quartz Monzonite*
  • Modifications:
    • Named
  • Dominant lithology:
    • Quartz monzonite
  • AAPG geologic province:
    • Okanogan province
Publication:

Miller, F.K., 1969, Preliminary geologic map of the Loon Lake quadrangle, Stevens and Spokane Counties, Washington: Washington Division of Mines and Geology, Geologic Map, GM-6, 1 sheet, 7 p., scale 1:62,500


Summary:

Unit is named the Silver Point Quartz Monzonite. Consists of porphyritic hornblende-biotite quartz monzonite forming a large pluton. Intrudes the Wallace and older formations of the Belt Series; in contact with unnamed plutonic rocks of the Loon Lake batholith; almost all contacts are concealed. Age is Mesozoic(?). (B1520)

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


Map showing publication footprint
  • Usage in publication:
    • Silver Point Quartz Monzonite*
  • Modifications:
    • Age modified
    • Geochronologic dating
  • AAPG geologic province:
    • Okanogan province
Publication:

Miller, F.K., 1971, The Newport Fault and associated mylonites, northeastern Washington, IN Geological Survey Research 1971: U.S. Geological Survey Professional Paper, 750-D, p. D77-D79.


Summary:

Age of the Silver Point Quartz Monzonite is modified from Mesozoic(?) to Tertiary based on radiometric (K-Ar) ages of 46.8 +/-1.7 Ma and 51.0 +/-5 Ma (both hornblende) and 46.7 +/-1.3 Ma and 48.1 +/-1 Ma (both biotite).

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


Map showing publication footprint
  • Usage in publication:
    • Silver Point Quartz Monzonite*
  • Modifications:
    • Age modified
    • Geochronologic dating
  • AAPG geologic province:
    • Okanogan province
Publication:

Miller, F.K., and Clark, L.D., 1975, Geology of the Chewelah-Loon Lake area, Stevens and Spokane Counties, Washington, with a section on potassium-argon ages of the plutonic rocks by Joan C. Engels: U.S. Geological Survey Professional Paper, 806, 74 p., (incl. geologic map, scale 1:62,500)


Summary:

Age of the Silver Point Quartz Monzonite is modified from Tertiary to Eocene based on radiometric (K-Ar) ages of 60 +/-2 Ma (hornblende) and 50 +/-1 (biotite).

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


Search archives

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 ([ ]).

Accessibility FOIA Privacy Policies and Notices

USA Gov U.S. Department of the Interior | U.S. Geological Survey
Supported by the National Cooperative Geologic Mapping Program
Page Contact Information: Personnel
Page Last Modified: Thu 21 May 2026 06:08:04 PM MDT