Sheep Mountain Occurrence, McGrath Mining District, Denali Borough, Alaska, USAi

Regional Level Types
Sheep Mountain Occurrence	Occurrence
McGrath Mining District	Mining District
Denali Borough	Borough
Alaska	State
USA	Country

Location: Reed and others (1978, locality 3) show this occurrence about 1.2 miles northwest of VABM Sheep west of the Tonzona River, in the east-central part of Section 4, T. 31 N., R. 17 W., of the Seward Meridian. Location is good to within 1/4 mile.
Geology: Reed and others (1978) described this locality as sporadic areas of manganese-rich metasedimentary rocks within the lower Paleozoic Pzsv unit which is considered to be correlative with similar units in the Kantishna Hills (Reed and Nelson, 1980). Gossans are spatially associated with felsic porphyry dikes and a Tertiary granite stock (Tmt) that may represent a cupola of underlying granitic rocks similar to the Tonzona pluton eight miles to the east-northeast (Reed and others, 1978; Reed and Nelson, 1980). Curtin, Karlson, O'Leary, Day, and McDougal (1978) describe clusters of high copper (+7,000 ppm) and zinc (+2500 ppm) values and scattered high lead (+10,000 ppm) values in heavy-metal concentrates from stream sediment samples collected around the VABM Sheep area. They suggest that these anomalous samples are asociated with the granite stock. Mineralization at this locality could be similar to the Mespelt (TL005), Hogback (TL006) or Boulder Creek (TL073) areas, which are associated with the Tonzona pluton.
Workings: Reconnaissance mapping, stream sediment and rock sampling by the U.S. Geological Survey (Curtin, Karlson, O'Leary, Day, and McDougal, 1978; Reed and others, 1978; Reed and Nelson, 1980) are all that have been described here. Curtin, Karlson, O'Leary, Day, and McDougal (1978) describe clusters of high copper (more than 7,000 ppm) and zinc (more than 2500 ppm) values and scattered high lead (more than 10,000 ppm) values in heavy-metal concentrates from stream sediment samples collected around the VABM Sheep area.
Age: Tertiary; mineralization is interpreted to be linked to the intrusive rocks mapped by Reed and Nelson (1980) as related to the Tonzona pluton which is determined to be 52.3 to 56.2 m.y. by the K/Ar method (Reed and Lanphere, 1972).

Commodities (Major) - Ag, Pb, Zn; (Minor) - Mn, Sb
Development Status: None
Deposit Model: Possibly Polymetallic veins (Cox and Singer, 1986; model 22c).

Other Databases

Link to USGS - Alaska:	TL072

Other Regions, Features and Areas containing this locality

References