Unnamed (east of Susitna Lodge airstrip)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals bornite; chalcocite; chalcopyrite; malachite; native copper
Gangue minerals epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale A-1
Latitude 63.086
Longitude -147.447
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of 2,420 feet, 0.75 mile due east of the south end of the Susitna Lodge airstrip. The map site is in the NW1/4 of sec. 19, T. 21 S., R. 2 E., of the Fairbanks Meridian. The location is accurate to within 200 feet.

Geologic setting

Geologic description

The area of this occurrence is underlain by the Middle or Upper Triassic Nikolai Greenstone, a thick sequence of subaerial and submarine basalt flows and minor interbedded volcaniclastic sedimentary rocks, aquagene and epiclastic tuff, breccia, argillite, and radiolarian chert (Nokleberg and others, 1992).
The deposit is in a hydrothermally altered shear zone in greenstone, and consists of quartz, epidote, chalcopyrite, and an iron carbonate mineral. Weathering produces malachite- and azurite-coated float and encrustations.
Glavinovich (1967) describes this occurrence as follows: 'Mineralized amygdaloidal andesite occurs in talus. Bornite, malachite and microscopic native copper associated with quartz pods occur in the andesite. The small quartz pods appear to have formed by replacement of the andesite. Bornite is later than the quartz and may, in part, be replacing it. Some of the strongly epidotized rock (greenstone) contains splashes of bornite, chalcocite (?) and malachite along fracture surfaces'.
Geologic map unit (-147.449254451602, 63.0855499421816)
Age of mineralization Triassic or younger.
Alteration of deposit Propylitic alteration of greenstone

Production and reserves

Indication of production None

References

MRDS Number 10307593

References

Glavinovich, P.S., 1967, Trace element copper distribution and areal geology in a portion of the Clearwater Mountains, Alaska: University of Alaska, Minerals Industry Research Laboratory, Report No. 10, 55 p.
Reporters D.L. Stevens (Stevens Exploration Management Corporation)
Last report date 4/7/2000