|Quadrangle map, 1:250,000-scale||CR|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The location of this prospect is from an old, small-scale map that lacks topographic contours. For this record, the prospect is about 0.5 mile east of Mount Miramar near the center of section 32, T. 75 S., R. 78 E. The location is probably accurate to within 0.5 mile.|
Geologic descriptionA silver-lead-zinc(-quartz?) vein in Silurian or Ordovician slate and argillite of the Descon Formation is exposed for nearly 300 feet along the south bank of a small creek and in old opencuts (Roehm, 1936 [PE 119-3]). The vein averages 18 to 24 inches thick and contains irregular masses of intergrown sphalerite and galena, with small amounts of pyrite and tetrahedrite. A sample across 22 inches of the vein contained a trace of gold, 9.20 ounces of silver per ton, 0.3 percent copper, 6.4 percent lead, and 15.3 percent zinc. A large Cretaceous granitic pluton crops out less than a mile to the south (Eberlein and others, 1983; Brew, 1996).
|Geologic map unit||(-133.590003503815, 55.3205926995677)|
|Mineral deposit model||Polymetallic vein (Cox and Singer, 1986; model 22c).|
|Mineral deposit model number||22c|
|Age of mineralization||May be related to the large Cretaceous granitic pluton to the south.|
|Workings or exploration||A few open cuts.|
|Indication of production||None|
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.
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.
Eberlein, G.D., Churkin, Michael, Jr., Carter, Claire, Berg, H.C., and Ovenshine, A. T., 1983, Geology of the Craig quadrangle, Alaska: U.S. Geological Survey Open-File Report 83-91, 52 p.
Roehm, J.C., 1936, Preliminary report of holdings of San Antonio Metals Company, Port San Antonio, Baker Island: Alaska Territorial Department of Mines Property Examination 119-3, 5 p.
Twenhofel, W.S., Robinson, G.D., and Gault, H.R., 1946, Molybdenite investigations in southeastern Alaska: U.S. Geological Survey Bulletin 947-B, p. 7-38.
|Reporters||D.J. Grybeck (Applied Geology)|
|Last report date||5/1/2004|