The Dome

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu; Pb
Ore minerals chalcopyrite; galena; pyrite
Gangue minerals calcite; limonite; quartz

Geographic location

Quadrangle map, 1:250,000-scale GU
Quadrangle map, 1:63,360-scale D-1
Latitude 62.81
Longitude -144.08
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is on the top and on the north side of The Dome, a prominent isolated mountain on the west side of Ahtell Creek. The prospect is in the SE1/4NW1/4, section 22, T. 12 N., R. 7 E., Copper River Meridian. The prospect is correctly located as number 3 on figure 5 of Richter (1966). It was mislocated by 1.2 miles as locality 7 of Richter and Matson (1972).

Geologic setting

Geologic description

The Dome prospect consists of veins and disseminated ore minerals in hornfelsed flows and possibly interbedded tuffs of the Pennsylvanian, Slana Spur Formation and in intrusive rocks of the Pennsylvanian to Permian, Ahtell Pluton (Richter, 1966; Richter, Lanphere, and Matson 1975; and Beard and Barker, 1989).
The silicic border phase of the Ahtell pluton contains stockworks of weakly metalliferous, quartz-calcite veins. The veins are as much as one foot thick and occupy joint sets. The predominant joint set strikes slightly west of north and dips moderately to the west. The veins contain sparse disseminated pyrite, chalcopyrite, and galena. The volcanic rocks also contain limonitic, hornfelsed volcanic rocks; the limonite probably formed by the oxidation of pyrite and chalcopyrite. A composite sample of an area about 400 feet by 100 feet in size contained from 0.05 to 0.1 percent copper (Richter, 1966, p. 31).
Geologic map unit (-144.082195766618, 62.8096095047613)
Mineral deposit model Porphyry Cu (Cox and Singer, 1986; model 17)
Mineral deposit model number 17
Age of mineralization Emplaced subseqent to or is related to the border phase of the Pennsylvanian to Permian, Ahtell pluton.
Alteration of deposit Quartz-sericite-pyrite alteration of the intrusive rocks is present on the northeast side of The Dome.

Production and reserves

Workings or exploration Mineral deposits exposed in shallow pits (Richter, 1964, 1966).
Indication of production None

References

MRDS Number A011840

References

Nokleberg, W.J., and (seven) others, 1994, Metallogeny and major mineral deposits of Alaska and Metallogenic map of significant metalliferous lode deposits and placer districts of Alaska, in Plafker, G. and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol.. G1, p. 855-904, Plate 11, scale 1:2,500,000.
Richter, D.H., Lanphere, M.A., and Matson, N.A., Jr., 1975, Granite plutonism and metamorphism, eeastern Alaska Range, Alaska: Geological Society of American Bulletin, v. 86, p. 819-820.
Reporters W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (U.S. Geological Survey)
Last report date 12/1/2000