Porphyry copper prospect in Alaska, United States

Names and other identifiers

Tract name Eastern Alaska Range and Wrangell Mountains (003pCu5002)
Site status prospect

Geographic location

Country United States
State or province Alaska
Geographic location -144.0327, 62.7888
Geologic map unit -144.0327, 62.7888
Nearby data

Geologic information

Deposit type Porphyry copper
Age determination method Geologic inference
Age range Pennsylvanian–Permian or Jurassic or Cretaceous (Inferred from ages of Ahtell pluton or younger plutons.)
Age reference geologic inference
Minerals arsenopyrite, chalcopyrite, galena, magnetite, malachite, sphalerite
Tectonic setting continental margin
Stratigraphic age Pennsylvanian–Permian or Jurassic or Cretaceous

Commodity and development information

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

Reference information

Comments Area is underlain by highly altered, border-phase rocks of the Pennsylvanian- to Permian-age Ahtell Creek quartz monzonite pluton; the pluton intrudes the Pennsylvanian- to Permian-age Tetelna Formation (mainly volcanic rocks). Both the Ahtell pluton and the Tetelna Formation are cut by dikes and irregular bodies of a mid-Jurassic-age complex that varies from diorite to quartz diorite; porphyry mineralization occurs mainly in the diorite complex and adjacent hornfels. Potassic alteration with potassium feldspar, biotite, and magnetite is nearest the mineralization; succeeded by a shell of sodium-calcium alteration with albite, actinolite, and magnetite; followed by an outermost shell of propylitic alteration with pyrite. Explored extensively since the discovery of placer deposits in the area in 1934; geologic mapping, sampling, and geochemical surveys, and aerial geophysical survey in 2006; 3 holes drilled in 2010 intersected extensive altered and mineralized rock. No reserves.
Study area name United States
References U.S. Geological Survey (2014a); Taylor (2010)
Site reference U.S. Geological Survey National Mineral Resource Assessment Team (2002)
Taylor, Chris, 2010, Technical report on the Chisna copper gold project, Chistochina mining district, south-central Alaska: Unpublished technical report prepared for International Tower Hill Mines Ltd., 107 p. (Available for download at, posted July 15, 2010).
U.S. Geological Survey, 2014a, Alaska Resource Data File (ARDF): U.S. Geological Survey database, accessed February 5, 2014, at