|Quadrangle map, 1:250,000-scale||MH|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect extends for about 0.3 mile along a gully from an elevation of about 4,000 to 5,500 feet. The center of the prospect is about 2.6 mile north-northeast of the mouth of the East Fork Maclaren River. It is about 0.6 mile west-northwest of the center of section 6, T.19 S., R. 7 E.|
The Maclaren Glacier deposit is along a steeply dipping, west-northwest-striking fault that separates Triassic limestone and gabbro to the south from Triassic argillite to the north (Rose, 1966; Nokleberg and others, 1991; 1992 [MF]; 1992 [Open-File]. Locally, the argillite is intruded by granodiorite of probable Cretaceous age. For about 0.3 mile, limestone is replaced by garnet, diopside, up to 20 percent magnetite, and locally sphalerite and chalcopyrite which is partly oxidized to azurite and malachite. The skarn zone is up to several hundred feet in width. The source of the mineralization may be the Cretaceous granodiorite (Nokleberg and others, 1991).The mineralized zones are only a few feet or less in length and width. A sample of magnetite skarn contained 16.9 percent iron, 2.8 percent copper, 0.12 percent chromium, 0.14 percent nickel, 45 parts per billion (ppb) gold, and 1 ppb silver (Kurtak and others, 1992). Locally the skarn contains more zinc and precious metals; one sample contained 5.5 percent zinc, 2.5 percent copper, 30 parts per million (ppm) silver, and 3.7 ppm gold (Nokleberg and others, 1991).
|Geologic map unit||(-146.495466445148, 63.3009715984482)|
|Mineral deposit model||Cu skarn? (Cox and Singer, 1986; model 18b?).|
|Mineral deposit model number||18b?|
|Age of mineralization||Possibly Cretaceous based on the nearness of a granitic pluton of that age.|
|Alteration of deposit||Base and precious metals in skarn zones in limestone.|
|Workings or exploration||Only limited sampling by state and federal agencies.|
|Indication of production||None|
Bittenbender, P.E., Bean, K.W., Kurtak, J.M., and Deininger, James Jr., 2007, Mineral assessment of the Delta River Mining District area, east-central, Alaska: U.S. Bureau of Land Management, Alaska Technical Report 57, 675 p.
Kurtak, J.M., Southworth, D.D., Balen, M.D., and Clautice, K.H., 1991, Mineral investigations in the Valdez Creek Mining District, south-central Alaska: U.S. Bureau of Mines Open-File Report 1-92, 658 p., 2 sheets, scale 1:250,000.
Nokleberg, W. J., Aleinikoff, J. N., Dutro, J. T., Lanphere, M. A., Silberling, N. J., Silva, S. R., Smith, T. E., and Turner, D. L., 1992, Map, tables, and summary of fossil and isotopic age data, Mount Hayes Quadrangle, eastern Alaska range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-D, 43 p., 1 sheet, scale 1:250,000.
Nokleberg, W.J., Aleinikoff, J. N., Lange, I. M.; Silva, S. R., Miyaoka, R. T., Schwab, C. E., Zehner, R. E., Bond, G. C., Richter, D. H., Smith, T. E., and Stout, J. H., 1992, Preliminary geologic map of the Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Open-File Report 92-594, 39 p. 1 sheet, scale 1:250,000.
Nokleberg, W.J., Lange, I.M., Roback, R.C., Yeend, Warren, and Silva, S.R., 1991, Map showing locations of metalliferous lode and placer mineral occurrences, mineral deposits, prospects, and mines, Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-C, 42 p., 1 sheet, scale 1:250,000.
|Reporters||W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS); D.J. Grybeck (Contractor, USGS)|
|Last report date||5/13/2012|