Unnamed (on Patterson Bay)

Occurrences, Probably inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Mo
Other commodities As
Ore minerals chalcopyrite; malachite; pyrrhotite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale PA
Quadrangle map, 1:63,360-scale C-2
Latitude 56.58743
Longitude -134.66074
Nearby scientific data Find additional scientific data near this location
Location and accuracy There is little information on these occurrences other than that they are on the east side of Patterson Bay and centered about 3.4 miles north-northwest of Patterson Point. The occurrences consist of 8 samples collected for about a mile, at or near the shoreline of the bay. Their center is near the southwest corner of section 9, T. 61 S., R. 69 E. The location is probably accurate to within 0.3 mile.

Geologic setting

Geologic description

There is apparently no record of any mineralization on the east side of Patterson Bay prior to the work of Bittenbender and others (1997, 1999), who collected 8 samples for about a mile along or near the shoreline. These samples, which are variously described as silicified zones in tonalite or mineralized inclusions of metamorphic rocks, contain less than 1 percent chalcopyrite. Disseminated pyrrhotite and copper staining with malachite occurs in some samples. The samples contain up to 970 parts per billion gold, 0.6 part per million (ppm) silver, 1,400 ppm copper, 109 ppm molybdenum, and 4,820 ppm arsenic. Loney and others (1975) map the rocks in the vicinity as Tertiary tonalite and granodiorite with abundant inclusions and septa of metamorphic rocks.
Geologic map unit (-134.66250019106, 56.587068814198)
Mineral deposit model Silicified zones in granitic rocks.
Age of mineralization Is younger than the Tertiary granitic host rocks.
Alteration of deposit Silicification of tonalite.

Production and reserves

Workings or exploration Only sampling by government geologists.
Indication of production None
Reserve estimates None.

Additional comments

The area is now within the South Baranof Wilderness Area and is closed to mineral exploration and mining.

References

References

Bittenbender, P.B., and Still, J.C., 1997, Mineral investigations on Chichagof and Baranof Islands, and vicinity, southeast Alaska: U.S. Bureau of Land Management, Alaska Open-File Report 67, 34 p.
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 Donald J. Grybeck (U.S. Geological Survey)
Last report date 2-Jan-05