|Quadrangle map, 1:250,000-scale||ID|
|Quadrangle map, 1:63,360-scale||A-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is at an elevation of about 950 feet, about 0.2 mile northeast of the top of hill 1265, a prominent feature about 3.5 miles east-northeast of the mouth of Michigan Creek. It is about 0.2 mile southwest of the center of section 23, T. 25N., R. 43W., Seward Meridian. The location is accurate.|
This prospect consists of a sulfide- and hematite-bearing breccia in hornfels derived from the Upper Cretaceous, Kuskokwim Group The prospect is adjacent to a small granite-porphyry intrusion (Miller and Bundtzen, 1994; Miller, Bundtzen, and Gray, 2005). Breccias with fragments of both sedimentary and volcanic rocks exist, which suggest that remnants of a volcanic field are also present. The granite porphyry has a 40K/40Ar age of 71.3 Ma (Miller and Bundtzen, 1994).The sulfide breccia covers an area at least 1,000 feet by 1,000 feet in area. The best mineralization occurs in the creek at the east side of the deposit, where stibnite-quartz gash veins cut hornfels. Other areas contain quartz breccia with masses of goethite produced by the oxidation of sulfide minerals. Grab samples of mineralization contain up to 250 parts per million (ppb) gold, 1.00 percent antimony, 200 parts per million (ppm) tin, 200 ppm tungsten, more than 14.0 ppm mercury, 5.0 ppm molybdenum, 610 ppm arsenic, and 20.00 percent iron. (McGimsey and others, 1988).
|Geologic map unit||(-157.201674755006, 62.240244258327)|
|Mineral deposit model||Polymetallic vein (Cox and Singer, 1986; model 22c); or peraluminous granite porphyry gold-polymetallic type of Bundtzen and Miller (1997).|
|Mineral deposit model number||22c|
|Age of mineralization||Unknown; the intrusion adjacent to the hornfels that hosts the deposit has a 40K/40Ar age of 71.3 Ma (Miller and Bundtzen, 1994).|
|Alteration of deposit||Iron oxide alteration.|
|Workings or exploration||The stibnite-quartz gash veins exposed at creek level was first noticed by the helicopter pilot David Blair in 1985. Samples were collected by the U.S. Geological Survey and Alaska Division of Geological and Geophysical Surveys in the 1980s (McGimsey and others, 1988). In 1996, Ventures Resources, Inc. acquired Alaska State prospecting sites over the prospect and continued to explore the site through 2003.|
|Indication of production||None|
Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 242-286.
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.
|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||5/25/2003|