Bonanza Hills

Occurrence, Inactive

Alternative names

Bonanza

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Pb; Sb
Ore minerals arsenopyrite; gold; stibnite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale LC
Quadrangle map, 1:63,360-scale D-5
Latitude 60.779
Longitude -154.506
Nearby scientific data Find additional scientific data near this location
Location and accuracy Approximately 230 m SW of the top of peak 3,710 in the Bonanza Hills. Locality 10 of Nelson and others (1985) and locality 157 of Eakins and others (1978). SW1/4SW1/4 sec. 14, T. 8 N., R. 30 W., of the Seward Meridian. Locality accurate within 400 m.

Geologic setting

Geologic description

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), and 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).
Rock chip analyses yield up to 46 ppm Au, 38 ppm Ag, and 1,400 ppm Pb. Gold concentration is estimated to be as much as 42.86 g/t (1.25 oz/ton). The bedrock is poorly exposed and additional sampling is needed to evaluate the prospect.
Geologic map unit (-154.508262759204, 60.7783247483162)
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, veins are is Late Cretaceous or younger.
Alteration of deposit Extensive sericitic and silicically altered quartz monzonite (Nokleberg and others, 1997).

Production and reserves

Workings or exploration Rock chip analyses yield up to 46 ppm Au, 38 ppm Ag, and 1,400 ppm Pb. Gold is estimated to be as much as 42.86 g/t (1.25 oz/ton).
Indication of production None
Reserve estimates No reserves
Production notes No production

References

MRDS Number A013005

References

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