Unnamed (near southwest end of Midnight Dome) (ARDF #WI132) Au

Unnamed (near southwest end of Midnight Dome)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Au
Other commodities	Cu
Ore minerals	gold; malachite; pyrite
Gangue minerals	quartz

Geographic location

Quadrangle map, 1:250,000-scale	WI
Quadrangle map, 1:63,360-scale	B-1
Latitude	67.4597
Longitude	-150.1562
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence is at an elevation of 3,700 feet, 0.2 mile west of hill 3860 on the south end of Midnight Dome. The location is accurate.

Geologic setting

Geologic description This occurrence consists of sulfide-bearing quartz veins in schist or quartzite (Eden, 2000). A sample of vein quartz found in float contains pyrite, malachite, and limonite, 179 ppb gold and 1,469 ppm copper. A sample of quartz vein collected in place contains pyrite and limonite, and 532 ppb gold. Eden (2000) interprets this occurrence as an extension of the system of auriferous quartz veins in the Nolan area. The rocks in the area are Upper Devonian chloritic schist and chloritic quartzite (Eden, 2000).
Geologic map unit	(-150.158947395062, 67.4592743933357)
Mineral deposit model	Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a)
Mineral deposit model number	36a
Alteration of deposit	Iron-oxide alteration.

Production and reserves

Workings or exploration	Only limited surface sampling and geologic mapping.
Indication of production	None

References

References Eden, K., 2000, Geology and gold mineralization of the Nolan area in the Brooks Range, Alaska: U.S. Bureau of Land Management Open-File Report 78, 87 p. Kurtak, J.M., Klieforth, R.F., Clark, J.M., and Williams, E.M., 1999, Mineral investigations in the Koyukuk mining district, northern Alaska--Progress Report: U.S. Bureau of Land Management Open-File Report 74, 158 p.
Reporters	J.M. Britton (Anchorage)
Last report date	5/14/2010