|Quadrangle map, 1:250,000-scale||CR|
|Quadrangle map, 1:63,360-scale||A-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Hope prospect is at an elevation of about 2,400 feet, about 0.3 mile south-southeast of elevation 2580. It is about in the center of the NE1/4 section 25, T. 77 S., R 86 E., and about 0.4 mile southeast of the better known and geologically similar Moonshine Mine (CR164).|
Geologic descriptionThe deposit at the Hope prospect is geologically similar to the one at the Moonshine Mine (CR164), about 0.4 mile to the northwest. The rocks in the vicinity of the Hope prospect are greenschist and marble of the Wales Group of Late Proterozoic and Cambrian age (Brew, 1996). The deposit is in folded marble. Prior to World War I, it was explored by a 25-foot adit, a 20-foot inclined shaft, and several trenches. As described by Wright and Wright (1906), the Hope prospect is a vein 1 to 10 feet thick that trends N65E. The marble hostrock is replaced by sphalerite and galena with low silver values. Minor garnet and epidote are also associated with the ore, and cerussite occurs locally as an oxidation product of galena. As described by Herreid and others (1978) and by Maas and others (1991, 1995), the deposit consists of veins and pods of quartz and calcite with galena, sphalerite, and minor chalcopyrite and pyrite that replace marble along numerous shear zones. The best showing examined by Maas and others (1991) was a 3-foot-thick pod of galena and sphalerite exposed in the adit. Samples contained up to 4.16 ounces of silver per ton, 8.71 percent lead, and 17.53 percent zinc. A high-grade galena-rich sample from a trench contained 28.23 percent zinc, 24.49 percent lead, and 4.21 ounces of silver per ton.
|Geologic map unit||(-132.38273062671, 55.167595624051)|
|Mineral deposit model||Silver-zinc-lead replacement deposit in marble.|
|Age of mineralization||Replacement deposit whose age is known no more closely than that it is in Late Proterozoic or Cambrian host rock.|
|Alteration of deposit||Some garnet and epidote reportedly are associated with this lead-zinc replacement deposit in marble.|
|Workings or exploration||The deposit was explored prior to World War I by a 25-foot adit, a 20-foot inclined shaft, and several trenches.|
|Indication of production||None|
|Production notes||Minor at best.|
Brew, D.A., 1996, Geologic map of the Craig, Dixon Entrance, and parts of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2319, 53 p., 1 sheet, scale 1:250,000.
Buddington, A.F., and Chapin, Theodore, 1929, Geology and mineral deposits of southeastern Alaska: U.S. Geological Survey Bulletin 800, 398 p.
Chapin, Theodore, 1916, Mining developments in southeastern Alaska: U.S. Geological Survey Bulletin 642-B, p. 73-104.
Cobb, E. H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Craig quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-869, 262 p.
Herreid, Gordon, Bundtzen, T.K., and Turner, D.L., 1978, Geology and geochemistry of the Craig A-2 quadrangle, Prince of Wales Island, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Geologic Report 48, 49 p.
Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.
Maas, K.M., Still, J.C., and Bittenbender, P.E., 1992, Mineral investigations in the Ketchikan mining district, Alaska, 1991 - Prince of Wales Island and Vicinity: U.S. Bureau of Mines Open-File Report 81-92, 69 p., 1 sheet, scale 1:20.
Maas, K.M., Still, J.C., Clough, A.H., and Oliver, L.K., 1991, Mineral investigations in the Ketchikan mining district, Alaska, 1990: southern Prince of Wales Island and vicinity: U.S. Bureau of Mines Open-File Report 33-91, 139 p., 12 sheets, scale 1:63,360.
|Reporters||D.J. Grybeck (Applied Geology)|
|Last report date||5/1/2004|