Unnamed (ridge southeast of Spruce Peak)

Prospect, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities As
Ore minerals goethite; jarosite; limonite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5804
Longitude -150.7001
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is about 0.10 mile southeast of Spruce Peak at an elevation of about 4550-4650 feet. It is in the SE1/4 SW1/4 section 29, T. 15 S., R. 16 W., Fairbanks Meridian. The prospect probably corresponds to occurrence 89 of Thornsberry, McKee, and Salisbury (1984, fig. K-8), but the site appears to be misplaced on their map.

Geologic setting

Geologic description

The country rocks at this prospect are metafelsite and greenschist of the lower Paleozoic Spruce Creek sequence (Bundtzen, 1981). The deposit consists of iron-stained quartz in a shear zone that strikes NE and dips moderately to the NW. The zone is about 20 to 30 feet wide, and locally is marked by orange and red soil that contains goethite and jarosite. If the quartz once contained sulfide minerals, they have been destroyed by oxidation. The jarosite, however, suggests that they included pyrite. The oxidized material contains traces of gold and silver and about 350 ppm arsenic (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 89).
Geologic map unit (-150.702383861538, 63.5798995753559)
Mineral deposit model Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization The quartz vein is assumed to be Eocene (see record MM091).
Alteration of deposit Silicified shear zone. Iron-oxide alteration.

Production and reserves

Workings or exploration The shear zone was explored by a pit.
Indication of production None

Additional comments

The prospect is in Denali National Park and Preserve.

References