Unnamed Occurrence (ARDF - SI147; northeast of Slocum Arm), Chichagof District, Sitka Borough, Alaska, USA
This page is currently not sponsored. Click here to sponsor this page.
Location: This occurrence is at an elevation of about 1,900 feet, about a mile east-northeast of Flat Cove in Slocum Arm. The occurrence is 0.3 mile south of the center of sec. 4, T. 51 S., R. 60 E. It is location P-95 of Bittenbender and others (1999), location 45 of Cobb (1972, 1978), and MAS no. 0021140136 (U.S. Bureau of Land Management, 2002). The location is accurate within about 0.5 mile.
Geology: Johnson and Karl (1985) map the rocks in the area of this occurrence 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 Border Ranges Fault, a regional-scale, high-angle fault that strikes northwest. Other faults in the area strike northwest, north, and east-southeast. One of them appears to offset the Border Ranges Fault for about 2 miles along a right-lateral fault. Cobb (1972, 1978), citing Loney and others (1963), describes the occurrence as disseminated sulfides and secondary copper minerals in greenstone. Bittenbender and others (1999), citing Ballard (1968) and Still and Weir (1981), describe the occurrence as a porphyry molybdenum deposit that extends over an area of at least a square mile. They specify the country rocks as greenstone intruded by granodiorite, but do not name the ore minerals.
Commodities (Major) - Mo
Development Status: None
Deposit Model: Porphyry molybdenum deposit? (Cox and Singer, 1986; models 21b).
1 entry listed. 1 valid mineral.
The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.
Ballard, J.D., 1968, Slocum Ann molybdenite prospect, Chichagof Island, Alaska: Alaska Division of Mines and Minerals, Mineral Investigation 114-2, 24 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. Cobb, E.H., 1972, Metallic mineral resources map of the Sitka quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-467, scale 1:250,000. Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Sitka quadrangle: U.S. Geological Survey Open-File Report 78-450, 124 p. Johnson, B.R, and Karl, S.M., 1985, Geologic map of western Chichagof and Yakobi Islands, southeastern Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map 1-1506, 1 sheet, scale 1:125,000. Loney, R.A., Berg, H.C., Pomeroy, J.S., and Brew, D.A., 1963, Reconnaissance geologic map of Chichagof Island and northwestern Baranof Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-388, 1 sheet, scale 1:250,000. Still, J.C., and Weir, K.R., 1981, Mineral land assessment of the west portion of western Chichagof Island, Alaska: U. S. Bureau of Mines Open-File Report 89-81, 168 p. Thorne, R.L., 1952, Slocum Arm molybdenum deposit, southeastern Alaska: Unpublished U. S. Bureau of Mines minerals memorandum, 2 p. (Report held by the Mineral Information Center, Bureau of Land Management, Juneau, Alaska.) 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] Wells, R.R., 1952, Mineral dressing report, Cobol molybdenum ore: Unpublished report, 3 p. (Report held by the Mineral Information Center, Bureau of Land Management, Juneau, Alaska.) Williams, J.A, 1928, Cobol deposit, Slocum Arm, Chichagof Island: Unpublished report, 3 p. (Report held by the Mineral Information Center, Bureau of Land Management, Juneau, Alaska.)