Unnamed (upper Flat Top Mountain)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Ag
Other commodities As
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SI
Quadrangle map, 1:63,360-scale C-6
Latitude 57.6162
Longitude -135.9859
Nearby scientific data Find additional scientific data near this location
Location and accuracy The location of this occurrence is only known approximately to be at an elevation of about 1,500 feet on Flat Top Mountain. For this record, the site is plotted 0.4 mile southwest of the center of sec. 17, T. 49 S., R. 59 E. It is location P-85 of Bittenbender and others (1999).

Geologic setting

Geologic description

Johnson and Karl (1985) map the rocks in the area of this occurrence as the Freeburn assemblage, a collage of kilometer-scale, fault-bounded, lozenge-shaped blocks of Cretaceous and Cretaceous(?) metasedimentary and metavolcanic rocks. The rocks are cut by numerous steeply-dipping, northwest-striking faults. They include the the southeastern extensions of the faults at the Hirst (SI087) and Chichagof (SI093) mines, which control the mineralization there. Bittenbender and others (1999), citing Still and Weir (1981), report that the occurrence is a quartz vein in graywacke. A sample of quartz float contained 2 parts per million (ppm) silver and 200 ppm arsenic.
Geologic map unit (-135.987716753572, 57.6158342272516)
Mineral deposit model Low-sulfide quartz vein.

Production and reserves

Workings or exploration Only surface sampling.
Indication of production None

Additional comments

The occurrence is in West Chichagof-Yakobi Wilderness.

References

References

Bittenbender, P., Still, J.C., Maas, K., and McDonald, M., Jr., 1999, Mineral resources of the Chichagof and Baranof Islands area, southeast Alaska: Bureau of Land Management, BLM-Alaska Technical Report 19, 222 p.
Reporters H.C. Berg (U.S. Geological Survey)
Last report date 10/16/2004