Arkansas

Prospect, Inactive

Commodities and mineralogy

Main commodities Ag
Other commodities As; Pb; Sb; Zn
Ore minerals arsenopyrite; boulangerite; galena; jamesonite; scorodite; sphalerite; stibnite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5587
Longitude -150.7746
Nearby scientific data Find additional scientific data near this location
Location and accuracy
The Arkansas prospect (Cobb, 1980 [OFR 80-363]) is at an elevation of about 3450 feet on a minor east-trending ridge at the head of the West Fork of Glen Creek. It is in the SE 1/4 NE 1/4 section 2, T. 16 S., R. 17 W., Fairbanks Meridian. The location is probably accurate within 500 feet. The Arkansas prospect is 1500 feet downstream from the Pension (MM081) prospect (Davis, 1923).
The Arkansas and Pension prospects are included in location 19 of Cobb (1972 [MF 366]). The Arkansas prospect is number 226 of Hawley and Associates (1978), 55 of Bundtzen (1981), and 69 of Thornsberry, McKee, and Salisbury (1984).

Geologic setting

Geologic description

The country rocks at the Arkansas prospect are metafelsite and greenschist (meta-andesite) of the lower Paleozoic Spruce Creek sequence; they are cut by a plug or dike of Tertiary basalt (Bundtzen, 1981). The prospect is in a half-mile-long fault block terminated on the east by a northwest-striking cross fault exposed along the West Fork of Glen Creek (Thornsberry, McKee, and Salisbury, 1984, fig. K-2).
The deposit consists of a 14-foot-thick shear zone containing quartz-sulfide veins. Individual veins are as much as 5 feet thick, and are separated by zones of sheared schist. The quartz contains galena, stibnite, and some sphalerite; a grab sample from a 5-foot-thick segment assayed 90 ounces of silver per ton (Davis, 1923). The principal vein is 1 to 4 feet thick, is vertical, and strikes N 70 E (Bundtzen, 1981). It contains arsenopyrite, extensively replaced by scorodite, and galena, boulangerite, jamesonite, and stibnite. A sample collected at the site in 1983 assayed a trace of gold, 2.33 ounces of silver per ton, 3.55 percent lead, 0.50 percent zinc, 1.9 percent antimony, and 5.65 percent arsenic (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 69).
Geologic map unit (-150.776883138404, 63.5581975716035)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization The deposit is assumed to be Eocene (see record MM091).
Alteration of deposit Oxidation of arsenic mineral.

Production and reserves

Workings or exploration The Arkansas vein was discovered in 1921(Davis, 1923). The prospect was mapped by Bundtzen (1981); an adit at the site was caved.
Indication of production Undetermined

Additional comments

The prospect is in Denali National Park and Preserve.

References

MRDS Number A011202

References

Bundtzen, T.K., 1981, Geology and mineral deposits of the Kantishna Hills, Mt. McKinley quadrangle, Alaska: M. S. Thesis, University of Alaska, College, Alaska, 238 p.
Reporters C.C. Hawley
Last report date 5/2/2001