Unnamed (on hill 1,220)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities As; Cd; Co; Cr; Ni; Sb
Ore minerals pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SM
Quadrangle map, 1:63,360-scale C-6
Latitude 61.61526
Longitude -158.08301
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on hill 1220, about 6 miles south of the Oskawalik River in an area of subdued topography. The occurrence is abut 0.4 mile south-southwest of the center of section 25, T. 18 N., R. 49 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description

This rocks at this occurrence consist of an east-west-trending, altered mafic dike that cuts hornfels of the Upper Cretaceous, Kuskokwim Group (Cady and others, 1955; M.L. Miller, unpublished field data, 1999). Quartz veins radiate away from the dike into the hornfels. The hornfels contains thin seams of fine-grained pyrite. The occurrence is on the southwest edge of a large, prominent, but poorly understood circular feature that extends over the north-central Sleetmute C-6 quadrangle south of the Oskawalik River (T.K. Bundtzen, unpublished field data, 1999). Isolated bodies of intrusive rocks and hornfels occur in the circular feature. The layered rocks appear to dip outward around this circular feature. One grab sample of quartz vein and hornfels contained 298 parts per billion (ppb) gold, 3,800 ppb silver, 230 parts per million (ppm) arsenic, 76 ppm antimony, 4.0 ppm cadmium, 39 ppm cobalt, 166 ppm chromium, and 211 ppm nickel. The elevated cobalt, chromium, and nickel values probably probably reflect background values in a nearby altered, mafic dike.
Geologic map unit (-158.085386167023, 61.6145570870493)
Mineral deposit model Polymetallic vein? (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c?
Alteration of deposit Silicification of hornfels.

Production and reserves

Workings or exploration The U.S. Geological Survey sampled the site in 1999.
Indication of production None



Reporters T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.) and M.L. Miller (U.S. Geological Survey)
Last report date 5/10/2003