|Quadrangle map, 1:250,000-scale||MH|
|Quadrangle map, 1:63,360-scale||A-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Norel occurrence is at an elevation of 3,300 feet on the east valley wall of the principal south tributary to Fielding Lake. It is in the NW1/4NW1/4 section 12, T. 21 S., R. 10 E., Fairbanks Meridian. This site corresponds to locality S86 in table 2 of Nokleberg and others (1991).|
This occurrence consists of disseminated pyrite and pyrrhotite in a serpentinized peridotite sill intruded by leucogabbro (W.T. Ellis, oral communication, 2001). A sample of the sulfide-bearing peridotite contained 0.12 percent nickel, 0.01 percent copper, 34 parts per billion (ppb) palladium, and 15 ppb platinum. A grab sample of pyritic, sheared, serpentinized, and iron-stained olivine cumulate near the gabbro contained 3,200 parts per million copper (Nokleberg and others, 1991).The country rocks are part of the Tangle ultramafic-mafic intrusive complex of Late Triassic age that may be a lopolithic feeder of the Nikolai greenstone basalt flows of the Wrangellia Terrane (W.T. Ellis, oral communication, 2001). The Tangle complex is a north-dipping layered intrusion of dunite, peridotite, and gabbro that varies from less than 2,000 feet thick to more than 4,000 feet thick and extends for more than 12 miles in length (W.T. Ellis, oral communication, 2001). The complex intrudes the Tangle Formation of Permian age (Nokleberg and others, 1991). It may connect with the Fish Lake complex at depth below the Amphitheater synform. Magmatic mineralization is synchronous with emplacement of Tangle complex, which is part of a 120-mile-long belt of mafic-ultramafic and associated rocks in the east-central Alaska Range.
|Geologic map unit||(-145.755436059143, 63.1147791530492)|
|Mineral deposit model||Ni-Cu-PGE in differentiated mafic-ultramafic sill.|
|Age of mineralization||Late Triassic.|
|Alteration of deposit||Local iron staining; serpentinization of the peridotite.|
|Workings or exploration||A sample of sulfide-bearing peridotite contained 0.12 percent nickel, 0.01 percent copper, 34 parts per billion (ppb) palladium, and 15 ppb platinum (W.T. Ellis, oral communication, 2001). A U.S. Geological Survey grab sample of pyritic, sheared, serpentinized, and iron-stained olivine cumulate near a gabbro contained 3,200 parts per million copper (Nokleberg and others, 1991).|
|Indication of production||None|
Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mount Hayes quadrangle, Alaska: U.S. Geological Survey Open-File Report 79-238, 140 p.
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 Science), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS)|
|Last report date||6/17/2002|