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Kingston

Prospect, Undetermined

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Commodities and mineralogy

Main commodities Au
Ore minerals gold
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale C-6
Latitude 55.609
Longitude -131.967
Nearby scientific data Find additional scientific data near this location
Location and accuracy The approximate location of the Kingston prospect is at an elevation of about 100 feet, 0.1 mile inland from the southwest shore of Helm Bay, and about 1.4 miles from the mouth of the bay. The site is in section 19, T. 72 S., R. 88 E., of the Copper River Meridian. It corresponds to loc. 32 in Elliott and others (1978). The location is accurate within about 0.3 mile.

Geologic setting

Geologic description

The country rocks at this site are flyschlike metasedimentary rocks that gradationally intertongue with andesitic and basaltic metavolcanic rocks (Berg and others, 1988, p. 17-19). The strata were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time (Brew, 1996, p. 27). Their premetamorphic age is uncertain. Berg and others (1988, p. 17) state that they closely resemble Upper Jurassic to mid-Cretaceous marine flysch and volcanic rocks nearby on Gravina Island. Near Smugglers Cove, they are intruded by metadiorite that may be transitional to the metavolcanic rocks (Berg and others, 1988, p. 20).
The deposit consists of a quartz-fissure-vein stockwork 6-30 feet wide in chloritic schist (Brooks, 1902, p. 58). The largest vein observed by Brooks was 6 feet wide. Assays of the deposit made in the early 1900s reportedly showed gold values of $2.50-$600/ton (Au at $20.67/oz.).
Fluid inclusion studies of quartz vein material from several of the Helm Bay lodes suggest that the veins formed at temperatures and pressures consistent with conditions during the Late Cretaceous greenschist-grade regional metamorphism (Maas and others, 1995, p. 184).
Geologic map unit (-131.968682991855, 55.6086372676745)
Mineral deposit model Low-sulfide gold-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Late Cretaceous.

Production and reserves

Workings or exploration Assays of the deposit made in the early 1900s reportedly showed gold values of $2.50-$600/ton (Au at $20.67/oz.) (Brooks, 1902, p. 58).
Indication of production None

References

MRDS Number A012308

References

Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map I-1807, 27 p., scale 1:250,000.
Brew, D.A., 1996, Geologic map of the Craig, Dixon Entrance, and parts of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2319, 53 p., 1 sheet, scale 1:250,000.
Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 p.
Elliott, R.L., Berg, H.C., and Karl, S.M., 1978, map and table describing metalliferous and selected non-metalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-73-B, 17 p., 1 sheet, scale 1:250,000.
Reporters H.C. Berg, USGS
Last report date 6/30/1999