Porphyry copper prospect in Alaska, United States

Names and other identifiers

Alternate names Unnamed (east of Caribou Mountain)
Tract name Koyukuk Arc (003pCu5007)
Site status prospect

Geographic location

Country United States
State or province Alaska
Geographic location -155.8346, 66.1809
Geologic map unit -155.8346, 66.1809
Nearby data

Geologic information

Deposit type Porphyry copper
Age (Ma) 81.9Ma
Age determination method K-Ar hornblende
Age range 81.9 ±3.0 Ma (Inferred from age of Zane Hills pluton.)
Age reference Miller and others (1966)
Minerals chalcopyrite, covellite, molybdenite, pyrite
Tectonic setting island arc
Stratigraphic age Late Cretaceous

Commodity and development information

Development status Prospect
Major commodities Au, Cu, Mo
Minor commodities Pb, Zn
Gold-Moly ratio -9999

Reference information

Comments Quartz veins and a quartz stockwork in Late Cretaceous-age monzonite porphyry and Early Cretaceous- to Late Jurassic-age andesitic volcanic rocks. A phyllic-argillic-propylitic alteration assemblage is distributed concentrically around the core of a monzonite porphyry intrusive. A grab sample of pyrite-bearing quartz contained 2.4 g/t gold, 300 ppm copper, 150 ppm lead, and 300 ppm zinc. Sediment samples from streams draining the intrusive contact are anomalous in Pb and Cu.
Study area name United States
References U.S. Geological Survey (2014a); Nokleberg and others (1996a); Miller and others (1966)
Site reference U.S. Geological Survey National Mineral Resource Assessment Team (2002)