Section 21

Porphyry copper prospect in Alaska, United States

Names and other identifiers

GMRAP ID 3387
Tract name Yukon-Tanana Upland (003pCu5003)
Site status prospect

Geographic location

Country United States
State or province Alaska
Geographic location -143.801, 64.2075
Geologic map unit -143.801, 64.2075
Nearby data

Geologic information

Deposit type Porphyry copper
Age (Ma) 102.7Ma
Age determination method Ar-Ar muscovite
Age range 102.7 ±0.4 Ma
Age reference Newberry and others (1998)
Minerals molybdenite, pyrite, scheelite, wolframite
Tectonic setting continental margin
Stratigraphic age Early Cretaceous

Commodity and development information

Development status Prospect
Major commodities Mo, W
Minor commodities Ag
Gold-Moly ratio -9999

Reference information

Comments Mineralization and alteration are associated with a quartz porphyry-aplite plug about 800 m in diameter; silicification is the dominant alteration type; in Mount Harper quartz-monzonite-granodiorite intrusive complex. Biotite from the Mount Harper granite gave a 40Ar/39Ar plateau age of 105.8 ±0.4 Ma (Newberry and others, 1998). Molybdenum mineralization discovered in 1977, following stream-sediment reconnaissance in 1975 and geologic mapping and rock sampling in 1976. One drill hole aborted early without penetrating mineralization in 1981.
Study area name United States
References U.S. Geological Survey (2014a); WGM Inc. (1978); U.S. Bureau of Mines (1995); Newberry and others (1998)
Site reference U.S. Geological Survey National Mineral Resource Assessment Team (2002)