Unnamed (west flank of Takotna Mountain) (ARDF #ID045) Ag

Unnamed (west flank of Takotna Mountain)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Ag
Other commodities	As; Cr; Hg
Ore minerals	pyrite
Gangue minerals	quartz

Geographic location

Quadrangle map, 1:250,000-scale	ID
Quadrangle map, 1:63,360-scale	D-1
Latitude	62.93419
Longitude	-156.05877
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence is near upper Beef Steak Creek at an elevation of about 1,300 feet. It is about 1.5 mile west to north-northwest of the top of Takotna Mountain in the SW1/4, section 23, T. 33 N., R. 36 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description The rocks in the vicinity of this occurrence are part of the Takotna pluton which has been dated as 71.0 Ma; the pluton intrudes shale and sandstone of the Upper Cretaceous, Kuskokwim Group (Miller and Bundtzen, 1994). Iron-oxide-stained hornfelsed sandstone contains minor disseminated pyrite and is cut by quartz veinlets. Samples contained up to 1,000 parts per million (ppm) chromium, 300 parts per billion (ppb) silver, 1.1 ppm mercury, and 30 ppm arsenic (Bundtzen and Laird, 1983; McGimsey and others, 1988; Miller, Bundtzen, and Gray, 2005).
Geologic map unit	(-156.061129486433, 62.9335597828639)
Mineral deposit model	Polymetallic vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number	22c
Age of mineralization	Probably Late Cretaceous, based on its host rock, the Takotna pluton that has been dated at 71.0 Ma (Miller and Bundtzen, 1994).
Alteration of deposit	Iron oxides produced by the weathering of pyrite and other (?) sulfides.

Production and reserves

Workings or exploration	Surface sampling was conducted by the Alaska Division of Geological and Geophysical Surveys in in 1978 and by the U.S. Geological Survey in 1985 (Bundtzen and Laird, 1983; McGimsey and others, 1985).
Indication of production	None

References

References Bundtzen, T.K., and Laird, G.M., 1983, Geologic map of the Iditarod D-1 quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Professional Report 78, scale 1:63,360. McGimsey, R.G., Miller, M.L., and Arbogast, B.F., 1988, Paper version of analytical results, and sample locality map for rock samples from the Iditarod quadrangle, Alaska: U.S. Geological Survey Open-File Report 88-421-A, 110 p., 1 sheet, scale 1:250,000. Miller, M.L., and Bundtzen, T.K., 1994, Generalized geologic map of the Iditarod quadrangle, Alaska showing potassium-argon, major oxide, trace element, fossil, paleocurrent, and archeological sample localities: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-A, 48 pages; 1 sheet, scale 1:250,000. Miller, M.L., Bundtzen, T.K., and Gray, J.E., 2005, Mineral resource assessment of the Iditarod quadrangle, west-central Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-B, scale 1:250,000, pamphlet.
Reporters	T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.), M.L. Miller (U.S. Geological Survey); and C.C. Hawley (Hawley Resource Group)
Last report date	5/16/2003