Norel

Occurrence, Active

Commodities and mineralogy

Main commodities Cu
Other commodities Ni; Pd; Pt
Ore minerals pyrite; pyrrhotite
Gangue minerals olivine; serpentine

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-4
Latitude 63.1152
Longitude -145.7532
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).

Geologic setting

Geologic description

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.

Production and reserves

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

References