|Quadrangle map, 1:250,000-scale||JU|
|Quadrangle map, 1:63,360-scale||A-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is at an elevation of approximately 1,700 feet on Douglas Island at the head of Nevada Creek. It is 0.75 mile southeast of McDonough Peak and 1 mile north of Stephens Passage, in the NE1/4NE1/4 section 19, T. 42 S., R. 68 E. of the Copper River Meridian. The location is accurate.|
The Homestake prospect was discovered in the early 1904 and was developed by a 145-foot adit with a 34-foot drift, and an open cut (Redman and others, 1989). The prospect was explored by Hecla Mining Company in 1990 and 1991 (Bundtzen and others, 1991; Swainbank and others, 1991). The deposit is in quartz-sericite phyllite interbedded with volcanic metaconglomerate. The phyllite is heavily iron-stained and contains 1 to 7 percent disseminated pyrite (Redman and others, 1989). The pyrite occurs both as cubes and as small, concordant lenses up to 0.1 inch long. Random clots with galena and sphalerite occur locally in the phyllite which is cut by a 6- to 14-inch thick quartz vein that can be traced for over 70 feet. The vein contains traces of galena and sphalerite. U.S. Bureau of Mines samples contained up to 0.8 ppm gold, 12.0 ppm silver, 735 ppm copper, 580 ppm lead, and 2,900 ppm zinc (Redman and others, 1989). The deposit is similar to the Alaska Treasure Mine (JU228), and the Yakima (JU207), Red Diamond (JU232), and Mammoth (JU229) prospects, which Newberry and others (1997) interpret as Cretaceous volcanogenic massive sulfide deposits.Southeastern Douglas Island is underlain mainly by Upper Jurassic to mid-Cretaceous marine argillite and graywacke, interbedded with basaltic volcanic and volcaniclastic rocks (Brew and Ford, 1985). The rocks are regionally metamorphosed to prehnite-pumpellyite or greenschist grade.
|Geologic map unit||(-134.34686506029, 58.2176697477557)|
|Mineral deposit model||Metamorphosed Kuroko massive sulfide deposit (Cox and Singer, 1986; model 28a)|
|Mineral deposit model number||28a|
|Age of mineralization||Newberry and others (1997) have interpreted this deposit as a Cretaceous volcanogenic massive sulfide deposit.|
|Alteration of deposit||Sericite.|
|Workings or exploration||The Homestake prospect was discovered in the early 1904 and was developed by a 145-foot adit with a 34-foot drift and an open cut (Redman and others, 1989). The prospect was explored by Hecla in 1990 and 1991(Bundtzen and others, 1991; Swainbank and others, 1991).|
|Indication of production||None|
Brew, D.A., and Ford, A.B., 1985, Preliminary reconnaissance geologic map of the Juneau, Taku River, Atlin, and part of the Skagway 1:250,000 quadrangles, southeastern Alaska: U.S. Geological Survey Open-File Report 85-395, 23 p., 2 sheets, scale 1:250,000.
Bundtzen, T.K., Swainbank, R.C., Wood, J.E., Clough, A.H., 1991, Alaska's Mineral Industry 1991: Alaska Division of Geological & Geophysical Surveys, Special Report 46, 89 p.
Newberry, R.J., Crafford, T.C., Newkirk, S.R., Young, L.E., Nelson, S.W., and Duke, N.A., 1997, Volcanogenic massive sulfide deposits of Alaska, in Goldfarb, R.J. and Miller, L. D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 120-150.
Redman, E.C., Maas, K.M., Kurtak, J.M., and Miller, L.D., 1991, Section D: Juneau Gold Belt subarea, in U.S. Bureau of Mines, Mineral investigations in the Juneau Mining District, Alaska, 1984-1988: Volume 2 - Detailed mine, prospect, and mineral occurrence descriptions: U.S. Bureau of Mines Special Publication VOL. 2D, 424 p., 19 sheets.
|Reporters||J.C. Barnett and L.D. Miller (Juneau, Alaska )|
|Last report date||12/15/2001|