Unnamed (Glacier Creek below Eighteen Gulch)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Fe
Other commodities As
Ore minerals arsenopyrite; goethite; jarosite; limonite; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5846
Longitude -150.916
Nearby scientific data Find additional scientific data near this location
Location and accuracy This unnamed occurrence is an elevation of about 1300 feet on the south side of the canyon of Glacier Creek, about 0.25 mile northwest of Eighteen Gulch. The occurrence corresponds to number 46 of Thornsberry, McKee, and Salisbury (1984). The location is probably accurate within 0.3 mile.

Geologic setting

Geologic description

This occurrence consists of sulfide and alteration minerals in sheared and altered metafelsite of the lower Paleozoic Spruce Creek sequence (Bundtzen, 1981; Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 46). Some vein quartz is present. Exposures are poor, but the mineralized felsite appears to trend northwesterly. Pyrite, the most abundant unoxidized metallic mineral, is disseminated in the metafelsite. Arsenopyrite may also be present, as suggested by a sample that contained 0.285 percent arsenic. Assays showed no precious metals or valuable base metals. The pyrite is extensively oxidized to limonite, chiefly goethite, and to jarosite. Iron oxides also stain the soil near the occurrence (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 46). The nature of the occurrence is uncertain; it appears to be weakly mineralized metafelsite possibly similar to that at occurreences MM018 and MM022.
Geologic map unit (-150.918290763669, 63.5840945803806)
Mineral deposit model Volcanogenic?
Age of mineralization Pyrite may have been an original volcanogenic(?) component of the lower Paleozoic Spruce Creek felsite (Bundtzen, 1981). The quartz veins may represent later epigenetic mineralization (see record MM091).
Alteration of deposit Iron-oxide alteration.

Production and reserves

Workings or exploration The site is a poorly exposed natural outcrop.
Indication of production None

Additional comments

The occurrence is in Denali National Park and Preserve.

References

References

Reporters C.C. Hawley
Last report date 4/29/2001