Occurrence, Active?

Commodities and mineralogy

Main commodities Au; Cu
Other commodities Ag; Hg
Ore minerals arsenopyrite; chalcopyrite; malachite
Gangue minerals quartz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale TA
Quadrangle map, 1:63,360-scale C-8
Latitude 60.5
Longitude -158.74
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 3,000 feet on a ridge 1,000 feet south of USGS benchmark Tippy, near the south boundary of the Taylor Mountains C-8 quadrangle. The map site is in the NW1/4 of section 27, T 5 N, R 54 W, of the Seward Meridan. It is locality 13 of Clark and others (1970) and locality 6 of Cobb (1972 [MF 384]; 1976 [OF 76-606]).

Geologic setting

Geologic description

At this locality, shale and graywacke, inferred to be part of the mid-Cretaceous Kuskokwim Group, is intruded and baked by a 15-foot wide, Cretaceous or Tertiary felsic dike (Clark and others, 1970). The limonite-stained dike contains some small cavities lined with apple green crystals of bindheimite (?), and small clots of acicular tourmaline. Quartz veins in the hornfels are up to 0.25 inch wide and contain 1 to 2 percent arsenopyrite and minor chalcopyrite; fracture surfaces are stained by malachite. Rock samples from this locality (Clark and others, 1970, samples AMM 777 and 799) contained up to 2,000 ppm B, 15,000 ppm Cu, 200 ppm Ag, 15 ppm Mo, 10,000 ppm Sb, 1.5 ppm Au, and greater than 10 ppm Hg. Rock samples collected up to 3,000 feet north-northwest along the ridge from this locality also contained anomalous levels of some metals, especially Ag, Cu, B, and Hg (Clark and others, 1970, sample localities 11 and 12).
Geologic map unit (-158.74226215877, 60.4992785694565)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization Late Cretaceous or Tertiary. Mineralization postdates deposition and deformation of mid-Cretaceous clastic sedimentary rocks and emplacement of Upper Cretaceous or Tertiary intrusive rocks.
Alteration of deposit Silicification (quartz veining in hornfels) and oxidation.

Production and reserves

Workings or exploration At least surface examination and sampling has taken place.
Indication of production None