Volcano Bay

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Zn
Ore minerals pyrite

Geographic location

Quadrangle map, 1:250,000-scale CB
Quadrangle map, 1:63,360-scale A-1
Latitude 55.2283
Longitude -162.0967
Nearby scientific data Find additional scientific data near this location
Location and accuracy Approximate location is west of head of Volcano Bay. Anomaly no. 55 of Christie (1974) described as 4 mi (6.4 km) north of Captain Harbor, west of Volcano Bay. Also occurrence no. 12 of MacKevett and Holloway (1977, p. 9).

Geologic setting

Geologic description

Color anomaly 12,000 ft by more than 5,000 ft (3,600 m by 1,500+ m) localized around a number of medium-grained granodiorite dikes and a 2,000 by 2,000+ ft (600 by 600+ m) granodiorite plug. Granodiorite intrudes andesite flows and volcaniclastic rocks of the Belkofski(?) Formation.
Geologic map unit (-162.098734552281, 55.2274291164587)
Mineral deposit model Polymetallic vein, epithermal gold vein
Mineral deposit model number 22c, 25
Age of mineralization Miocene or younger
Alteration of deposit Granodiorite, in general, is moderately propylitically altered, and contains traces of disseminated pyrite. Locally, granodiorite is completely propylitically altered, having up to 4 percent pyrite either disseminated or in fracture fillings. Although andesitic country rocks generally are not altered, they locally contain zones of intense alteration (destruction of feldspars and mafic minerals) up to 200' (60 m) wide containing as much as 5 percent pyrite.

Production and reserves

Workings or exploration Brief reconnaissance mapping and 15 soil and silt samples (Christie, 1974). Sample results showed generally low copper and molybdenum, zinc to 109 ppm, silver to 2.2 ppm, and gold to 0.2 ppm. Christie (1974) reported covered area to west of anomaly was large enough to hide a porphyry system but lack of copper mineralization makes possibility unlikely.
Indication of production None

Additional comments

Interpretation of andesitic host rocks as Belkofski Formation is based on the reporter's (F.H. Wilson) knowledge of the area and not on Christie's (1974) or MacKevett and Holloway's (1977) report.

References

MRDS Number A106050

References

Christie, J.S., 1974, Aleut-Quintana-Duval 1974 joint venture, final report: Unpublished Quintana Minerals Corporation report, 24 p., 3 appendices, 2 maps. (Report held by the Aleut Corporation, Anchorage, Alaska.)
Reporters G.D. DuBois, F.H. Wilson
Last report date 5/9/1994