National mineral assessment tract PC36 (Low-sulfide Au-quartz vein)

Tract PC36
Geographic region Pacific Coast
Tract area 21,800sq km
Deposit type Low-sulfide Au-quartz vein
Deposit age Mesozoic

Deposit model

Model code 36a
Model type descriptive
Title Descriptive model of low-sulfide Au-quartz veins
Authors Byron R. Berger
URL https://pubs.usgs.gov/bul/b1693/html/bull8x2r.htm
Source https://pubs.er.usgs.gov/publication/b1693

Rationale

Explained by William J. Pickthorn and Michael F. Diggles
On the choice of deposit models
The Northern Cascades contains belts of low- to moderate-grade regionally metamorphosed marine sedimentary and volcanic rocks which are penetratively deformed and cut by high-angle regional-scale faults and crosscutting serpentine bodies. Consideration of this tract as permissive for low-sulfide Au-quartz vein deposits (Berger, 1986) is supported by numerous small gold mines and occurrences in this area that are considered to belong to this model type.
On the delineation of permissive tracts
This tract was defined principally on the presence of belts of low- to moderate-grade regionally metamorphosed marine sedimentary and volcanic rocks depicted on the Washington State geologic map (Hunting and others, 1961) and the personal knowledge of the assessors. Although this tract contains no major low-sulfide Au-quartz vein deposits, several major mesothermal gold districts in similar or possibly equivalent rocks are found to the north in Canada.
Important examples of this type of deposit
No major low-sulfide Au-quartz deposits are recognized in this tract.
On the numerical estimates made
The team was unable to make an estimate because of lack of information on the nature of the gold occurrences in the tract.
References
Berger, B.R., 1986, Descriptive model of low-sulfide Au-quartz veins, in Cox, D.P., and Singer, D.A., eds., Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 239.

Geographic coverage

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