Bonanza Hills; VABM Trail Occurrence, Bristol Bay Mining District, Lake and Peninsula Borough, Alaska, USAi

Regional Level Types
Bonanza Hills; VABM Trail Occurrence	Occurrence
Bristol Bay Mining District	Mining District
Lake and Peninsula Borough	Borough
Alaska	State
USA	Country

None.
Location: Along an unnamed N-NW flowing tributary of the Mulchatna River, about 5.6 km north of the juncture of Glacier Creek with Bonanza Creek. This is aproximately locality 8 of Nelson and others (1985) and locality 179 of Eakins and others (1978). SW1/4NE1/4 sec. 6, T. 8 N., R. 30 W., of the Seward Meridian. Locality accurate within 500 m.
Geology: The site includes: narrow zones of en echelon arsenopyrite and stibnite-bearing quartz veins in shale and sandstone country rock adjacent to a small quartz monzonite plutons and dacite porphyry. The extensive sericitic and silic altered quartz monzonite is one of the numerous small intrusive bodies found in the central part of the Lake Clark 1:250,000 scale quadrangle mapped and identified by Eakins and others (1978); (Nelson and others, 1983, unit TKi5). One of these plutons yielded a potassium-argon biotite age of 71.3 +/- 2.1 m.y. (Eakins and others, 1978). The plutons intrude Lower Cretaceous shale and sandstone, part of the regionally extensive Upper Jurassic and Lower Cretaceous flysch (Nokleberg and others, 1997). Anomalous stream sediment concentrates near small intrusive bodies containing disseminated chalcopyrite and pyrite. Eakins and others (1978) reported pan concentrates that yield anomalous gold (70 ppm), tin (1,000 ppm), and tungsten (2,000 ppm).
Workings: Pan concentrates yield anomalous 70 ppm Au, 1,000 ppm Sn, and 2,000 ppm W (Eakins and others, 1978).
Age: Rocks of the quartz monzonite unit yielded a potassium-argon biotite age of 71.3 +/- 2.1 m.y. (Eakins and others, 1978). Thus the veins in the host rock aer Late Cretaceous or younger.
Alteration: Extensive sericitic and silic alteration of the quartz monzonite (Nokleberg and others, 1997).
Production: No production
Reserves: No reserves

Commodities (Major) - Au; (Minor) - Sn, W
Development Status: None
Deposit Model: Polymetallic vein (Cox and Singer, 1986; model 22c)

Other Databases

Link to USGS - Alaska:	LC009

Other Regions, Features and Areas containing this locality

References