Main commodities | Cu |
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Ore minerals | bornite; chalcopyrite; malachite |
Gangue minerals | quartz |
Quadrangle map, 1:250,000-scale | MH |
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Quadrangle map, 1:63,360-scale | A-4 |
Latitude | 63.1468 |
Longitude | -145.9979 |
Nearby scientific data | Find additional scientific data near this location |
Location and accuracy | The occurrence is at an elevation of 4,100 feet in a small cirque west-northwest of Lower Tangle Lake. It is in the SE1/4SW1/4 section 27, T. 20 S., R. 9 E., Fairbanks Meridian. This location corresponds to locality S75 in table 2 of Nokleberg and others (1991), locality 9 of Cobb (1979 [OFR 79-238]), and an occurrence described by Stout (1976, p. 30 and plate 1). |
Geologic descriptionThis occurrence includes two types of deposits. One consists of pods as much as a foot thick of massive chalcopyrite and bornite in metabasalt of Nikolai Greenstone of Late Triassic age (Stout, 1976). The other consists of chalcopyrite, bornite, and copper oxide-bearing quartz veins in north-northeast-striking joints in the greenstone. Malachite-coated copper nuggets occur in stream gravels in a nearby cirque. The quartz veins are localized in north-northeast-trending joints that cut across the folded limbs of the Amphitheater syncline. The veins post-date late Jurassic deformation and are probably either Cretaceous related to regional metamorphism and granitic plutonism (Nokleberg and others, 1986) or early Tertiary (Stout, 1976). | |
Geologic map unit | (-146.000145685583, 63.1463762323776) |
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Mineral deposit model | Basaltic Cu (Cox and Singer, 1986; model 23). |
Mineral deposit model number | 23 |
Age of mineralization | Late Triassic and Cretaceous. |
Indication of production | None |
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MRDS Number | A011791 |
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References | |
Reporters | W.T. Ellis (Alaska Earth Science), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS) |
Last report date | 6/17/2002 |