|Quadrangle map, 1:250,000-scale||CH|
|Quadrangle map, 1:63,360-scale||C-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Victor prospect is at an elevation of about 4,200 feet on the ridge between Big Spruce Creek and Mathews River. It is about 4.2 miles north of the mouth of Limestone Creek on the Bettles River, and about 0.2 mile north of the center of section 5, T. 32 N., R. 8 W. A map showing the geology of the area and the location of this and the other deposits of the Chandalar Copper Belt is Figure C-1 of Kurtak and others (2002).|
The Victor prospect was discovered by Bear Creek Mining Company in 1967 along what would would become known as the Chandalar Copper Belt (Kurtak and others, 2002). Bear Creek and several other companies (Midwest Oil Company, WGM Inc., Arctic Resources Inc., and Venture Resources Corp.) explored the property into the 1990s. The work apparently consisted mainly of mapping, sampling, and geochemical and geophysical surveys but there is an reference to some drilling.
The Victor prospect is one of several Cu deposits in the Chandalar area which have been described by Newberry and others (1986) as mostly skarn deposits. They are all northwest of a belt of Devonian(?) granitic rocks informally named the Horace Mountain plutons that are probably genetically related to these deposits (Dillon and others, 1996). Many of these Cu skarns exhibit both prograde garnet and pyroxene and retrograde epidote and actinolite mineral assemblages. Newberry and others (1986) stated that the mineralogy, mineralization, and alteration of these skarns tend to place them in the category of continental-margin, porphyry-related copper skarns.
The deposits at the Victor prospect are copper skarns that are exposed at several places near the contact of metamorphosed, Early Devonian hornblende granodiorite that has intruded Ordovician calcareous schist and limestone (Dillon and others, 1996; Kurtak and others, 2002). The skarns contain chalcopyrite, pyrite, pyrrhotite, magnetite, and minor bornite, in disseminations, stringers, and pods. The meta-granodiorite contains only a trace of copper but shows propylitic and sericitic alteration. The skarn is retrograded and consists mainly of garnet, clinopyroxene, actinolite, epidote, calcite, quartz, and chlorite (Nicholson, 1990).A hand specimen from the Victor prospect, described in Newberry and others (1986), contained 1.1 percent copper, 5.5 parts per million (ppm) silver, less than 0.14 ppm gold, and negligible lead and zinc. Young and others (1997) reported that hundreds of meters of samples assayed 0.1 to 0.6 percent copper, with some values as high as 5.5 percent copper, 150 ppm molybdenum, and 0.41 ppm gold. Kurtak and others (2002) sampled several areas of skarn with chalcopyrite, pyrite, and pyrrhotite; the best two samples averaged 6.22 percent copper, 18.5 ppm silver, and 354 parts per billion gold. Nicholson (1990) estimated that skarn pods at the Victor and Eva (CH063) prospects have a resource of 50,000 tons with an average grade of 2 percent copper.
|Geologic map unit||(-149.386457107438, 67.6300961147933)|
|Mineral deposit model||Copper skarn (Cox and Singer, 1986; model 18b).|
|Mineral deposit model number||18b|
|Age of mineralization||Devonian(?) based on Early Devonian Pb/Pb zircon ages from the nearby Baby Creek batholith and Horace Mountain plutons (Dillon and others, 1996).|
|Alteration of deposit||The Devonian meta-granodiorite shows propylitic and sericitic alteration; the skarns near the intrusive show retrograde alteration.|
|Workings or exploration||The Victor prospect was discovered by Bear Creek Mining Company in 1967 along what would would become known as the Chandalar Copper Belt (Kurtak and others, 2002). Bear Creek and several other companies (Midwest Oil Company, WGM Inc., Arctic Resources Inc., and Venture Resources Corp.) explored the property into the 1990s. The work apparently consisted mainly of mapping, sampling, and geochemical and geophysical surveys but there is an reference to some drilling.|
|Indication of production||None|
|Reserve estimates||Nicholson (1990) estimated that skarn at the Victor and Eva (CH063) prospects have a resource of 50,000 tons with an average grade of 2 percent copper.|
This prospect is on Doyon Ltd. selected lands; for more information, contact Doyon Ltd., Fairbanks, Alaska.MAS No. 0020310065
Cobb, E.H., and Cruz, E.L., 1983, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in the Chandalar quadrangle, Alaska: U.S. Geological Survey Open-File Report 83-278, 91 p.
DeYoung, J.H., Jr., 1978, Mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-B, 2 sheets, scale 1:250,000.
Dillon, J.T., Reifenstuhl, R.R., and Harris, G.W., 1996, Geologic map of the Chandalar C-5 quadrangle, southeastern Brooks Range, Alaska: Alaska Division of Geological and Geophysical Surveys, Professional Report 104, 2 sheets, scale 1:63.360.
Kurtak, J.M., Klieforth, R.F., Clark, J.M., and Maclean, E.A., 2002, Mineral investigations in the Koyukuk mining district, northern Alaska, 2 vols.: Bureau of Land Management, Alaska Technical Report 50, 845 p.
Newberry, R.J., Allegro, G.L., Cutler, S.E., Hagen-Levelle, D.D., Adams, D.D., Nicholson, L.C., Weglarz, T.B., Bakke, A.A., Clautice, K.H., Coulter, G.A., Ford, M.J., Myers, G.L., and Szumigala, D.J., 1997, Skarn deposits of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 355-395.
Newberry, R.J., Dillon, J.T., and Adams, D.D., 1986, Regionally metamorphosed calc-silicate-hosted deposits of the Brooks Range, northern Alaska: Economic Geology, v. 81, p. 1728-1752.
Nichol, D.L., 1983, Evaluation of the mineral potential of Doyon Ltd.'s Blocks 5 and 22: Unpublished report for Doyon Ltd. (on file at Doyon Ltd., Fairbanks, Alaska).
Nicholson, L.M., 1990, Porphyry copper, copper skarn, and volcanogenic massive sulfide occurrences in the Chandalar copper district, Alaska: University of Alaska, Fairbanks, Master of Science thesis,164 p.
WGM Inc., 1973, Progress report 1973, Chandalar district: Unpublished report for Midwest Oil Corporation, 46 p.
WGM inc., 1974, Chandalar district progress report 1974: Unpublished report for AMOCO Minerals, 37 p.
WGM Inc., 1977, 1077 Annual progress report, Doyon Ltd. project v. II, Luna area: Unpublished report 78-04 for Doyon Ltd. 15 p. (on file at Doyon Ltd., Fairbanks, Alaska).
WGM Inc., 1980, 1979 annual profess report, Block 5-Wiseman Chandalar Copper Belt: Unpublished report 80-06 for Doyon Ltd., 28 p. (on file at Doyon Ltd., Fairbanks, Alaska).
Young, L.E., St. George, P., and Bouley, B., 1997, Porphyry copper deposits in relation to the magmatic history and palinspastic restoration of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 306-333.
|Reporters||J.M. Britton (Anchorage, Alaska); D.J. Grybeck (Contractor, U.S. Geological Survey)|
|Last report date||4/18/2010|