Unnamed (northwest of Gilroy Mountain) (ARDF #WI143) Ag, As, Au

Unnamed (northwest of Gilroy Mountain)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Ag; As; Au
Other commodities	Bi; Cu; Sb; Zn
Ore minerals	arsenopyrite; chalcopyrite; sphalerite

Geographic location

Quadrangle map, 1:250,000-scale	WI
Quadrangle map, 1:63,360-scale	A-4
Latitude	67.2451
Longitude	-151.5814
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence is at an elevation of about 3,300 feet about 2.0 miles west-northwest of the top of Gilroy Mountain. The site corresponds to the location of samples 50 and 51 in Dillon and others (1981). The location is accurate.

Geologic setting

Geologic description This occurrence consist of a stockworks of small sulfide veins in marble (Dillon and others, 1981 [AOF 133B]). They collected two grab samples. A fine-grained actinolite marble contains narrow veins of chalcopyrite and sphalerite; a gray marble contains veins of arsenopyrite, sphalerite, and traces of chalcopyrite. The arsenopyrite veins were as much as 10 cm thick. The arsenopyrite-bearing sample contains 10 ppm silver, 10% arsenic, 15 ppm gold, 50 ppm bismuth, and 300 ppm antimony. The other sample contained no anomalous metal values. The rocks in the area are mainly Devonian, Ambler metavolcanic rocks (Dillon and others, 1986).
Geologic map unit	(-151.584130785595, 67.244642326395)
Mineral deposit model	Polymetallic vein? (Cox and Singer, 1986; model 22c?).
Mineral deposit model number	22c?

Production and reserves

Workings or exploration	Only surface sampling.
Indication of production	None

References

MRDS Number	A011963
References Dillon, J.T., Cathrall, J.B., and Moorman, M.A., 1981, Geochemical reconnaissance of the southwest Wiseman quadrangle-summary of data on rock samples: Alaska Division of Geological and Geophysical Surveys Open-File Report 133B, 164 p.
Reporters	J.M. Britton (Anchorage)
Last report date	8/9/2002