Porphyry copper prospect in Alaska, United States

Names and other identifiers

Alternate names Painted River
Tract name Western Alaska Range (003pCu5004)
Site status prospect

Geographic location

Country United States
State or province Alaska
Geographic location -154.4713, 59.2329
Geologic map unit -154.4713, 59.2329
Nearby data

Geologic information

Deposit type Porphyry copper
Age determination method Geologic inference
Age range Jurassic(?)
Age reference geologic inference
Minerals bornite, chalcopyrite, magnetite, malachite, pyrite
Tectonic setting continental margin
Stratigraphic age Jurassic(?)

Commodity and development information

Development status Prospect
Major commodities Au, Cu
Minor commodities Ag, Fe
Gold-Moly ratio -9999

Reference information

Comments Breccia pipe at least 300 ft in diameter in Jurassic(?)-age intermediate and mafic igneous rocks. The strongest mineralization in the pipe is near its walls, and consists of angular blocks of intensely sericitized, fine- to medium- grained gabbro,with 1 to 5 percent sulfides, in a matrix of coarse amphibole, biotite, and plagioclase. Drilled 18 holes in 1990 and 1991 for a total of 5,300 ft. Drilled 5 holes in 2006 for a total of 750 m; three of the 5 holes cut mineralization: notable intercepts include (1) 73.5 m that contained 0.31 percent copper and 0.28 gram of gold per ton, (2) 51.0 m that contained 0.48 percent copper and 0.46 gram of gold per ton, and (3) 7.50 m that contained 0.36 percent copper and 0.53 gram of gold per ton. Two areas of mineralized breccia were identified. The westernmost breccia is a pipe-like body about 30 by 50 m in size; it is cut by a narrow fault with malachite and by thin sulfide- and magnetite-rich veins. The other breccia is a mineralized, pipe-like body about 75 by 150 m in size that extends to a depth of at least 75 m; it has disseminated copper minerals as well as sulfide-bearing veinlets. Propylitic and potassic alteration: development of secondary biotiteand potassium feldspar; local sericitization.
Study area name United States
References U.S. Geological Survey (2014a); Alix Resources Corp. (2008)
Site reference U.S. Geological Survey National Mineral Resource Assessment Team (2002)