Makushin River

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Gangue minerals pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale UN
Quadrangle map, 1:63,360-scale C-3
Latitude 53.8667
Longitude -166.8
Nearby scientific data Find additional scientific data near this location
Location and accuracy Headwaters of south fork of Makushin River. Anomaly no. 19 of Christie (1974).

Geologic setting

Geologic description

A pale yellow-brown to dark red-brown color anomaly 3,000 ft (900 m) in diameter located in volcanic flows and pyroclastic rocks of the Unalaska Formation (see Drewes and others, 1961) is reported by Christie (1974). These volcanic rocks are intruded by numerous small dikes and plugs of diorite containing sparse disseminated pyrite. Post-mineralization andesite and gabbro dikes are present. 'Fracture sulfides were important in several areas that are now totally leached. No evidence for copper mineralization was seen there or elsewhere in the system (Christie, 1974).'
Geologic map unit (-166.80188419054, 53.8658435784481)
Mineral deposit model Epithermal gold veins (Cox and Singer, 1986; model 25c?).
Mineral deposit model number 25?
Age of mineralization Cenozoic
Alteration of deposit Argillic alteration is characteristic with there being local development of silicification and sericitic alteration. Leaching (of sulfides?) is complete in fractures and only partial where they are disseminated (Christie, 1974).

Production and reserves

Workings or exploration Limited reconnaissance mapping and 8 soil(?) samples. Samples contained up to 2.4 ppm silver, one contained 0.44 ppm gold.
Indication of production None


MRDS Number A106011


Christie, J.S., 1974, Aleut-Quintana-Duval 1974 joint venture, final report: Unpublished Quintana Minerals Corporation report, 24 p., 3 appendices, 2 maps.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 Damon Bickerstaff, F.H. Wilson
Last report date 5/3/1994