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Unnamed (north of Discovery Camp)

Occurrence, Inactive

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Commodities and mineralogy

Main commodities Au
Other commodities Ag; As; Hg; Sb; W
Ore minerals iron oxide
Gangue minerals quartz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale ID
Quadrangle map, 1:63,360-scale B-4
Latitude 62.48843
Longitude -157.90025
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at the top of a prominent, north-trending peak about 2.7 mile north-northeast of Discovery Camp on Otter Creek. The occurrence is at an elevation of about 2,200 feet and about 0.3 mile east of the center of section 25, T. 28 N., R. 47 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description

This occurrence consists of iron-oxide-stained rubble of a quartz vein of unknown extent. The vein is in an aureole of hornfels that overlies an intrusion exposed to the west at the Golden Ground prospect (ID116). The mineralized rubble also contains fragments of brecciated, hornfelsed sandstone with tourmaline rosettes (Bundtzen and others, 1992; Miller and Bundtzen, 1994; Miller, Bundtzen, and Gray, 2005). The prospect was developed by one trench that is now sloughed and overgrown. Grab samples of mineralized rubble contain up to 1,000 parts per billion (ppb) gold, 1,000 ppb silver, 650 parts per million (ppm) antimony, more than 2,000 ppm arsenic, 2,000 ppm boron, 50 ppm tungsten, and more than 10.0 ppm mercury (McGimsey and others, 1988). The high boron value probably reflects the presence of tourmaline.
Geologic map unit (-157.902650067981, 62.487746509233)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization Undated; probably related to a nearby intrusion that is 70.6 Ma (Bundtzen and others, 1992).
Alteration of deposit Tourmaline-mica greisen is developed in the hornfels.

Production and reserves

Workings or exploration A trench cut prior to 1986 explored the mineralized area. The area was sampled by the U.S. Geological Survey in 1986 (McGimsey and others, 1988; Bundtzen and others, 1992).
Indication of production None

References

References

Bundtzen, T.K., Miller, M.L., Laird, G.M., and Bull, K.F., 1992, Geology and mineral resources of Iditarod mining district, Iditarod B-4 and eastern B-5 quadrangles, southwestern Alaska: Alaska Division of Geological and Geophysical Surveys Professional Report 97, 46 p., 2 sheets, 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 5/19/2003