Unnamed (upper Horsfeld Creek)

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu; Pb
Other commodities Ag; Au; Zn
Ore minerals chalcopyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale NB
Quadrangle map, 1:63,360-scale A-1
Latitude 62.0541
Longitude -141.26
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is 1,000 feet north of the summit of peak 5945 between two unnamed north tributaries to Horsfeld Creek. The site is at an elevation of about 5,700 feet, about 0.2 mile east of the center of section 7, T. 3 N., R. 23 E. of the Copper River Meridian. This is locality 6 of Richter and others (1973), locality 51 of Richter and others (1975), and National Park Service locality WRST-85. Cobb and Richter (1980) included this locality as an 'Unnamed occurrence'. It is located to within a few hundred feet.

Geologic setting

Geologic description

A 2-foot-wide quartz vein that contains chalcopyrite cuts volcanic breccia of the Cretaceous, Chisana Formation (Richter and others, 1973; 1975). A grab sample of the vein contained 0.04 parts per million (ppm) gold, 30 ppm silver, 10,000 ppm copper, 7,000 ppm lead, and 700 ppm zinc (Matson and Richter, 1971 [OFR 71-202]). This occurrence is about 5,000 feet northwest of the contact of the Chisana Formation and the mid-Cretaceous, Klein Creek pluton (Richter and others, 1973; Richter, Lanphere, and Matson 1975).
Geologic map unit (-141.262132951814, 62.053775456966)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization Mid-Cretaceous? The mineralization may be related to emplacement of the Klein Creek pluton which has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and Matson, 1975).

Production and reserves

Indication of production None

Additional comments

The prospect is in the Wrangell-St. Elias National Preserve.


MRDS Number A011421


Reporters Travis L. Hudson (Applied Geology)
Last report date 11/24/2002