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Prospect, Undetermined

Commodities and mineralogy

Main commodities Cu
Ore minerals malachite; pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale SI
Quadrangle map, 1:63,360-scale B-6
Latitude 57.433
Longitude -135.7702
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Next prospect is at an elevation of about 1,000 feet, about 1.7 miles southeast of the head of Slocum Arm. The prospect is 0.2 mile west-southwest of the center of sec. 22, T. 51 S., R. 60 E. It is location P-96 of Bittenbender and others (1999) and MAS no. 0021140199 (U.S. Bureau of Land Management, 2002). The location is accurate within 0.5 mile.

Geologic setting

Geologic description

Johnson and Karl (1985) map the rocks in the area of this prospect as Triassic(?) greenstone and marble, Cretaceous(?) phyllite, and the Freeburn assemblage, a collage of kilometer-scale, fault-bounded, lozenge-shaped blocks of Cretaceous and Cretaceous(?) metasedimentary and metavolcanic rocks. The contact between the Triassic(?) strata and the Cretaceous/Cretaceous(?) strata is the regional-scale Border Ranges Fault, a high-angle, northwest-striking fault that passes through just southwest of the prospect.
Bittenbender and others (1999), citing Loney and others (1963), describe the prospect as malachite and disseminated pyrite and pyrrhotite in greenstone. Triassic(?) greenstone elsewhere on northwest Chichagof Island generally contains primary sulfide minerals that are about the same age as the greenstone host rock (see, for example, SI035 and SI036).
Geologic map unit (-135.7719973963, 57.4326431520014)
Mineral deposit model Basaltic copper? (Cox and Singer, 1986; model 23).
Mineral deposit model number 23?
Age of mineralization Triassic(?) greenstone elsewhere on northwest Chichagof Island generally contains primary sulfide minerals that are about the same age as the greenstone host rock.

Production and reserves

Indication of production Undetermined

Additional comments

The prospect 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.
U.S. Bureau of Land Management, 2002, Alaska mineral locations database report (Sitka quadrangle), July 2, 2002, 205 p. [http://imcg.wr.usgs.gov/dem.html]
Reporters H.C. Berg (U.S. Geological Survey)
Last report date 10/16/2004