Unnamed (Mallard Bay, Knight Island)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Zn
Ore minerals chalcopyrite; pyrite
Gangue minerals epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-3
Latitude 60.2951
Longitude -147.8062
Nearby scientific data Find additional scientific data near this location
Location and accuracy The occurrence is located on the east side of Mallard Bay at an elevation of 250 feet. It is located in the NE1/4 section 1, T. 2 N., R. 9 E., of the Seward Meridian. This is location S-48 of Jansons and others (1984). This location is accurate to within a quarter of a mile.

Geologic setting

Geologic description

From near the shoreline several iron-stained mineralized shear zones, 3.5 to 12 feet wide, can be traced to an elevation of about 250 feet. The bedrock is greenstone of the Orca Group of early Tertiary age (Nelson and others, 1985). Stringers of massive pyrite, chalcopyrite, and quartz-epidote veins are concentrated along the zones (Kurtak and Jeske, 1986). The nearby gabbro-greenstone contact contains no visible mineralization. There is a one-foot-wide unmineralized breccia in the greenstone as well as epidote fracture fillings. Three chip samples were collected across mineralized zones in the greenstone. They contained from 50 ppm to 3.3 percent copper and as much as 140 ppm zinc (Kurtak and Jeske, 1986).
Geologic map unit (-147.808267416828, 60.2945443801523)
Mineral deposit model Cyprus massive sulfide (Cox and Singer, 1986; model 24a)
Mineral deposit model number 24a
Age of mineralization Tertiary or younger; the mineralization is in rocks of the Orca Group of Tertiary age.

Production and reserves

Workings or exploration No workings are reported in the literature. The U.S. Bureau of Mines visited the occurrence in the early 1980s and did not find any signs of prospecting. Three chip samples were collected across the 3.5- to 12-foot-wide mineralized zones in the greenstone; they contained from 50 ppm to 3.3 percent copper and as much as 140 ppm zinc (Kurtak and Jeske, 1986).
Indication of production None

References