Prospect, Probably inactive

Alternative names


Commodities and mineralogy

Main commodities Au; Cu
Other commodities Ag; Fe; W
Ore minerals chalcopyrite; magnetite; malachite; scheelite
Gangue minerals carbonate

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-6
Latitude 63.2458
Longitude -146.6753
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect lies on the divide between the East and West Forks Maclaren River at an elevation of 5,500 feet and in the NW1/4 section 30, T. 19 S., R. 6 E., Fairbanks Meridian. The prospect corresponds to locality A18 of Kurtak and others (1992) and Kardex site number KX68-79 (Heiner and Porter, 1972).

Geologic setting

Geologic description

At this prospect, magnetite-rich metabasalt of the Nikolai Greenstone of Late Triassic age is intruded by quartz monzonite of Jurassic or Cretaceous age (Nokleberg and others, 1982). Numerous malachite-stained chalcopyrite-bearing quartz-carbonate veins cut the basalt. The largest of the veins is about 10 feet wide and and can be followed at least 100 feet along strike.
The veins, like the metabasalt, are rich in magnetite. Some of the veins contain a significant amount of gold; others are enriched only in copper (Kurtak and others, 1992, table A18). Selected sample 2641 of a 1.4-foot-wide magnetite-rich vein in basalt contained 1.26 ounces of gold per ton and 0.12 percent tungsten; it possibly contained scheelite. Copper-rich veins average about 2.1 percent copper; a 4.5-foot-wide magnetite-carbonate vein that could be followed for about 100 feet assayed 6.3 percent copper (sample 3212). This vein also assayed 0.81 ounce of gold per ton and 0.78 ounce of silver per ton.
Partly because of the gold content of the veins, the U.S. Bureau of Mines assigned moderate potential to the prospect, but noted that the exposed length of veins was short (Kurtak and others, 1992).
Geologic map unit (-146.677566167797, 63.2453648533329)
Mineral deposit model Copper-magnetite veins; probably some affinity to both Basaltic Cu and Cu skarn (Cox and Singer, 1986; models 23 and 18b).
Mineral deposit model number 23, 18b
Age of mineralization The magnetite-rich mineralization is probably associated with the intrusion of the Jurassic or Cretaceous quartz monzonite.
Alteration of deposit Oxidation of iron- and copper-bearing minerals.

Production and reserves

Workings or exploration Viking claims were located on the prospect for copper, silver, and gold by Vernon Hanson in 1961 (Heiner and Porter, 1972; Kardex site number KX68-79). The site was sampled in the early 1990s by the U.S. Bureau of Mines (Kurtak and others, 1992).
Indication of production None

Additional comments

The veins contain significant concentrations of gold and copper, but exposed strike lengths are short (Kurtak and others, 1992).