Larson, Erickson, and Allen

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu; Zn
Ore minerals chalcopyrite; pyrite; pyrrhotite; sphalerite
Gangue minerals calcite; epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-3
Latitude 60.2729
Longitude -147.8609
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is located in the SE1/4 section 10, T. 2 N., R. 9 E., of the Seward Meridian, at or near sea level. It is on the northeast shore of Copper Bay, Knight Island. This is location 111 of Cobb and Richter (1972), location 139 of MacKevett and Holloway (1977), locations 234-235 of Cobb and Tysdal (1980), and location S-45 of Jansons and others (1984). This location is accurate to within a quarter of a mile.

Geologic setting

Geologic description

The prospect consists of a shear zones in pillow basalt of the Orca Group of early Tertiary age (Nelson and others, 1985). The shear zones are healed by quartz and epidote. Sulfide minerals occur in numerous quartz veins in shear zones, and they slightly impregnate the adjacent country rock (Johnson, 1918 [B 662-C, p. 218]). Pyrrhotite is the dominant sulfide mineral, and traces of chalcopyrite and pyrite are also present. A random chip sample of pillow basalt with sulfide minerals, quartz, and epidote, contained 18 ppm copper and 99 ppm zinc (Kurtak and Jeske, 1986). No other information is available from the literature.
Geologic map unit (-147.862977811584, 60.2723463919075)
Mineral deposit model Cyprus massive sulfide (Cox and Singer, 1986; model 24a)
Mineral deposit model number 24a
Age of mineralization Tertiary or younger; the occurrence is in rocks of the Orca Group of Tertiary age.
Alteration of deposit Basalt altered to epidote.

Production and reserves

Workings or exploration Johnson (1918 [B 662-C, p. 218]) reported a cabin and a shallow shaft near the high tide line, but he provided no details. Kurtak and Jeske (1986) could not find any signs of workings when they visited the prospect during the 1980-84 field seasons. A grab sample from this area contained 18 ppm copper and 99 ppm zinc (Kurtak and Jeske, 1986).
Indication of production None

References

MRDS Number A010373

References

Reporters Jeff A. Huber and Carol S. Huber (Anchorage)
Last report date 3/1/2001