|Quadrangle map, 1:250,000-scale||MZ|
|Quadrangle map, 1:63,360-scale||A-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Several lode occurrences are in a mile-square area on the valley wall and hills west of central Black Sand Creek. The site corresponds to ADGGS station 92BT311 at the center of 5 sample sites (Solie and others, 1993 [Public-data file 93-18]). It is on a small knob at an elevation of 1,400 feet, on the east boundary of section 12, T. 5 S., R. 19 E., Kateel River Meridian. The location is accurate.|
Patton and others (1977) describe the rocks in the area of these occurrences as Permian to Jurassic, spilitic basalt and diabase largely metamorphosed to greenstone, and Lower Cretaceous, massive, poorly-sorted conglomerate with pebble- to cobble-size clasts, chiefly of mafic igneous rocks and chert. Dillon and others (1983) describe the rocks as greenschist-grade, lower Mesozoic and upper Paleozoic basalt, diabase, hornblende gabbro, and basaltic volcaniclastic rocks. The dominant rock type at the occurrences is meta-basalt (greenstone). Small bodies of medium-grained biotite granite, aplite, pegmatite, and leucocratic granite also crop out in the area. The granitic rocks are assumed to be Lower Cretaceous in age based on a K-Ar date of 111+/- 3 Ma on biotite from the Melozitna pluton which is probably related to the granitic rocks at this site (Patton and others, 1977).The Alaska Division of Geological & Geophysical Surveys collected 8 rock samples and a panned-concentrate sample in and near the area of these occurrences (Solie and others, 1993 [Public-data file 93-18]). Two float samples of greenstone or gabbro with sulfides contained up to 64 parts per million (ppm) bismuth, 252 ppm copper, 1,467 ppm manganese, 94 ppm tin, 43 ppm tellurium, 452 ppm vanadium, and 133 ppm zinc. Bedrock samples included layered mafic rock with probable chromite; basalt with sparse chalcopyrite and malachite; magnetite-bearing pyroxene-plagioclase gabbro; gabbro with whitish veins; and ultramafic rock. These samples contained up to 1.3 ppm silver, 10 parts per billion (ppb) gold, 73 ppm bismuth, 1,491 ppm chromium, 930 ppm copper, 20 ppb palladium, 20 ppb platinum, 64 ppm tin, 45 ppm tellurium, 966 ppm vanadium, and 113 ppm zinc.
|Geologic map unit||(-154.907817129255, 65.07191687338)|
|Mineral deposit model||Duluth Cu-Ni-PGE (Cox and Singer, 1986; model 5a); Noril'sk (Cox and Singer, 1986; model 5b); possible Polymetallic vein overprint (Cox and Singer, 1986; model 22c)|
|Mineral deposit model number||5a, 5b, 22c|
|Age of mineralization||At least some of the mineralization (chiefly platinum, palladium, and chromium) probably is syngenetic with the Permian to Jurassic mafic and ultramafic rocks. There may be an overprint of later mineralization related to the Lower Cretaceous granite bodies.|
|Workings or exploration||Only limited sampling by government geologists.|
|Indication of production||None|
Dillon, J.T., Adams, D.D., Adler, Penny, 1983, Geologic map of the Melozitna A-4 Quadrangle, Alaska: Alaska Division of Geological & Geophysical Surveys Report of Investigation 83-18, 1 sheet, scale 1:63,360.
Patton, W.W., Jr., Miller, T.P., Chapman, R.M., and Yeend, W., 1977, Geologic map of the Melozitna quadrangle, Alaska: U.S. Geological Survey Open-File Report 77-147, 1 sheet, scale 1:250,000.
Solie, D.N., Bundtzen, T.K., Bowman, N.D., and Cruse, G.R., 1993, Land selection unit 18 (Melozitna, Ruby, Nulato, and Kateel River quadrangles): References, DGGS sample locations, geochemical and major oxide data: Alaska Division of Geological & Geophysical Surveys, Public Data File 93-18, 20 p., 1 sheet, scale 1:250,000.
|Reporters||D.J. Szumigala (Alaska Division of Geological and Geophysical Surveys)|
|Last report date||2/1/2005|