GMRAP ID | 9 |
---|---|
Tract name | Eastern Alaska Range and Wrangell Mountains (003pCu5002) |
Site status | deposit |
Country | United States |
---|---|
State or province | Alaska |
Geographic location | -142.733333333, 62.216666667 |
Geologic map unit | -142.733333333, 62.216666667 |
Nearby data |
Deposit type | Porphyry copper |
---|---|
Age (Ma) | 105Ma |
Age determination method | K-Ar |
Age range | 114 ±3.4 to 105 ±4.0Ma (Inferred from age of Nabesna pluton.) |
Age reference | Richter, Lanphere, and Matson (1975) |
Minerals | anhydrite, biotite, chalcopyrite, chlorite, epidote, gold, kaolinite, magnetite, molybdenite, pyrite, sericite |
Associated rocks | granodiorite porphyry, quartz monzonite porphyry, andesite, rhyodacite, basalt, granodiorite, marble, metavolcanic rocks, quartz diorite, siltstone, skarn, volcaniclastics |
Tectonic setting | continental margin |
Stratigraphic age | Early Cretaceous |
Development status | Occurrence |
---|---|
Major commodities | Cu, Mo |
Tonnage (Mt) | 500Mt |
Cu grade (%) | 0.3% |
Mo grade (%) | 0.02% |
Contained copper | 1,000,000t |
Gold-Moly ratio | -9999 |
Comments | This porphyry copper-molydenum deposit was discovered in the 1960s and explored by some diamond drilling. The deposit is estimated to contain 500 million tons with an average grade of 0.30 percent copper and 0.02 percent molybdenum; some gold and silver values are also likely (Richter and others, 1975). The host rocks are altered over a 2.5 square kilometer area (Richter, 1973). The alteration includes a 600- by 2,000(?)-m central zone with abundant chlorite, minor biotite and potassium feldspar, spotty sericite, and late anhydrite veins. Discovered in the 1960s and explored by some diamond drilling. |
---|---|
Study area name | United States |
References | Hollister (1978); Nokleberg and others (1987); Richter and others (1975); Young and others (1997); Singer and others (2008) |
Site reference | U.S. Geological Survey National Mineral Resource Assessment Team (2002) |