Bonanza Hills

Occurrence, Inactive

Alternative names

VABM Trail

Commodities and mineralogy

Main commodities Au
Other commodities Sn; W
Ore minerals chalcopyrite; gold; pyrite; scheelite

Geographic location

Quadrangle map, 1:250,000-scale LC
Quadrangle map, 1:63,360-scale D-5
Latitude 60.815
Longitude -154.604
Nearby scientific data Find additional scientific data near this location
Location and accuracy 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.

Geologic setting

Geologic description

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 silicic 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).
Geologic map unit (-154.606264346001, 60.8143232556481)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization 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 are Late Cretaceous or younger.
Alteration of deposit Extensive sericitic and silicic alteration of the quartz monzonite (Nokleberg and others, 1997).

Production and reserves

Workings or exploration Pan concentrates yield anomalous 70 ppm Au, 1,000 ppm Sn, and 2,000 ppm W (Eakins and others, 1978).
Indication of production None
Reserve estimates No reserves
Production notes No production

References

MRDS Number A013007

References

Reporters M.L. Miller (USGS); D.P. Bickerstaff (USGS)
Last report date 6/15/1998