Unnamed (north tributary to Unaluk River)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Pt
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale HG
Quadrangle map, 1:63,360-scale D-5
Latitude 58.892
Longitude -161.452
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on the south side of an east-west oriented mountain between the Kinegnak River and the headwaters of the Unaluk River. It is at an elevation of about 750 feet on the north side of a saddle, in the E1/2 of section 9, T 15 S, R 73 W, of the Seward Meridian. It is probably located to within about 1/3 mile. It is locality 2 of Cobb (1972 [MF 362]; 1980 [OF 80-909]).

Geologic setting

Geologic description

On June 1, 1972, Allen L. Clark (U.S.G.S.) told E. H. Cobb that lode gold had been found at this location (Cobb, 1980, p. 33 [OF 80-909]). Cobb (1972 [MF 362]) showed this location to be on the the south side of an east-west oriented mountain between the Kinegnak River and the headwaters of the Unaluk River. It is at an elevation of about 750 feet on the north side of a saddle marking the approximate south contact of a mafic pluton and sedimentary rocks (Hoare and Coonrad, 1979). The mafic plutons in the general area are gabbroic rocks that locally contain olivine and show compositional layering. They have yielded Jurassic K/Ar ages that range from 159 to 187 Ma (Hoare and Coonrad, 1978). The country rocks intruded by the pluton are Paleozoic to Mesozoic sedimentary rocks that include limestone near the contact just to the west of this locality. Fechner (1988) mapped and sampled the general area. A pan-concentrate sample from a saddle within the pluton contained 240 ppb Au and 125 ppb Pt; a chert sample from the contact zone at this location contained 70 ppb Au; and three small flakes of gold were recovered from a 0.1-cubic-yard sample of alluvium from a creek draining the east side of the pluton.
Geologic map unit (-161.454218654381, 58.8912181385485)
Age of mineralization If the mineralization is epigenetic, then it is probably Early Jurassic or younger. It can be as old as the nearby pluton, which is correlated with nearby mafic plutons that have been K/Ar dated as Jurassic in age (Hoare and Coonrad, 1978).

Production and reserves

Workings or exploration No workings have been reported at this occurrence.
Indication of production None

References