Unnamed (southeast of Blunt Mountain)

Prospects, Undetermined

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb; Zn
Other commodities Barite
Ore minerals barite; chalcopyrite; galena; hematite; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale A-5
Latitude 55.128
Longitude -131.374
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site represents a line of old prospects between 200 and 800 feet elevation near the southeast foot of Blunt Mountain, and 1.0-1.5 miles southeast of the highest point on the mountain. The prospects are in sections 2 and 3, T. 78 S., R. 93 E., of the Copper River Meridian. The coordinates are for the approximate center of the half-mile-long line of prospects. The site corresponds to locs. 1 and 2 in Berg (1972 [I 684]), loc. 145 in Elliott and others (1978), and locs. 30a-d and 31 in Karl (1992). The location is accurate within about 0.1 mile.

Geologic setting

Geologic description

The country rocks in the area of this site are recrystallized, Upper Triassic carbonate and clastic rocks, rhyolite, and basalt (Berg, 1972). The rocks are complexly folded and faulted, and were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. All of the mineral deposits are hosted by metarhyolite and tuff.
The deposits consist of sparsely mineralized, sulfide-bearing, locally vuggy quartz veins up to 3 feet thick, in sheared, sericitized, and chloritized rhyolite and tuff (Berg, 1972, locs. 1, 2; Karl, 1992, locs. 30, 31). Some of the mineralized shear zones are up to 10 feet wide and have been traced on the surface for 40 feet. The chief sulfide mineral is pyrite, which also is sparsely disseminated in the altered rhyolite adjacent to the veins. Other sulfide minerals, inferred from sample assays, probably include galena, chalcopyrite, sphalerite, and barite. Minor hematite is reported in some of the veins.
The deposits were explored in the 1930s by a 110-foot-long, NE-trending adit, and in the 1970s by trenches, shallow pits, and soil surveys (Berg, 1972; Karl, 1992). Selected samples of mineralized quartz veins and stringers collected by the USGS in the 1930s contained up to 0.05 oz. Au/ton, 20.60 oz. Ag/ton, 4.63% Cu, 9.75% Pb, and 13.14% Zn (Berg, 1972. loc. 1). Samples of variously mineralized quartz veins and of altered rhyolite collected by the USGS in the early 1990s contained as much as 2.68 oz. Au/ton, 8.75 oz. Ag/ton, 200 ppm Cu, 1000 ppm Pb, 200 ppm Zn, and more than 5000 ppm Ba (Karl, 1992, locs. 30a, 31). A limonitic quartz vein sampled in the 1970s by private interests contained 0.93 oz. Au/ton; and soil samples that they collected contained up to 0.9 ppm Au (Karl, 1992, loc. 30c).
Geologic map unit (-131.375681347249, 55.1276596046058)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization Probably Late Cretaceous or younger.
Alteration of deposit Rhyolite is sericitized and pyritic in shear zones and adjacent to quartz veins.

Production and reserves

Workings or exploration The deposits were explored in the 1930s by a 110-foot-long, NE-trending adit, and in the 1970s by trenches, shallow pits, and soil surveys (Berg, 1972; Karl, 1992). Selected samples of mineralized quartz veins and stringers collected by the USGS in the 1930s contained up to 0.05 oz. Au/ton, 20.60 oz. Ag/ton, 4.63% Cu, 9.75% Pb, and 13.14% Zn (Berg, 1972. loc. 1). Samples of variously mineralized quartz veins and of altered rhyolite collected by the USGS in the early 1990s contained as much as 2.68 oz. Au/ton, 8.75 oz. Ag/ton, 200 ppm Cu, 1000 ppm Pb, 200 ppm Zn, and more than 5000 ppm Ba (Karl, 1992, locs. 30a, 31). A limonitic quartz vein sampled in the 1970s by private interests contained 0.93 oz. Au/ton; and soil samples that they collected contained up to 0.9 ppm Au (Karl, 1992, loc. 30c).
Indication of production None

References