Copenhagen Hill

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu
Other commodities Ag; Au
Ore minerals chalcopyrite; pyrite
Gangue minerals quartz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale MD
Quadrangle map, 1:63,360-scale C-4
Latitude 63.515
Longitude -154.626
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Copenhagen Hill prospect is situated near the summit of an isolated hill about 1 mile (1.6 km) north of Cottonwood Creek at an elevation of 2,450 feet (746 m) in Section 9, T. 23 S., R. 22 E., of the Kateel River Meridian. Location is known to within about 500 feet (152 m).

Geologic setting

Geologic description

The Copenhagen Hill prospect is the western-most copper-gold showing in a seven mile (11 km)-long, northeast trending belt of porphyry-like prospects through the central Mystery Mountains (DiMarchi and others, 1997). The hornfels is intruded by several porphyry dikes. Unlike other prospects in the Mystery Mountains, sulfides such as chalcopyrite, pyrite, and pyrrhotite are found in abundance in the hornfels. Quartz-tourmaline breccias are common within a 450 feet by 300 feet (137 m by 91 m) mineralized area. The Copenhagen Hill prospect is believed to be Late Cretaceous, based on inferred isotopic age of Mystery Mountains plutonic rocks (Moll and others, 1981). No assay data was found for this summary.
Geologic map unit (-154.628342958353, 63.5144018381842)
Mineral deposit model Porphyry Cu-Au (Cox and Singer, 1986; model 20c).
Mineral deposit model number 20c
Age of mineralization The Copenhagen Hill prospect is believed to be Late Cretaceous, based on inferred isotopic age of Mystery Mountains plutonic rocks (Moll and others, 1981).
Alteration of deposit Tourmaline.

Production and reserves

Workings or exploration Regional exploration conducted by WGM Inc. in 1978 found the Copenhagen prospect (Andrews, 1978). During 1988 to 1990, ACNC conducted exploration including an airborne geophysical survey. During 1991 to 1997, ASA Inc. continued detailed exploration work at the Copenhagen prospect and throughout the Mystery Mountains. The Copenhagen Hill prospect is believed by DiMarchi and others (1997) to represent the western-most copper-gold anomalous area in a district-wide, porphyry-style metallic zonation (DiMarchi and others, 1997). No assay data was found for this summary.
Indication of production None
Reserve estimates None.

Additional comments

See Pork Chop (MD031), Mystery Mountains East (MD028), Frozen Creek (MD032), and Tarn (MD027) prospects.

References

MRDS Number 10307780

References

Andrews, Tom, 1978, Summary of Progress, Doyon Project, Mystery Mountains (Block 10): Anchorage, Alaska, WGM Inc., 24 p. (Held by Doyon, Limited, Fairbanks, Alaska, as proprietary report 78-42).
DiMarchi, J.J., and Frantz, P.S., 1997, Annual Report for 1997-Doyon Option Lands, Block 10: ASA Inc.-Montague Gold Joint Venture Report, Volume II: Unpublished report, 189 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)
Reporters Bundtzen, T.K. (Pacific Rim Geological Consulting)
Last report date 6/6/1998