|Quadrangle map, 1:250,000-scale||CR|
|Quadrangle map, 1:63,360-scale||C-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Lone Jack prospect is at an elevation of about 400 feet, about 1.2 mile east-southeast of the mouth of McGilvery Creek on Salmon Lake. It is just north of the center of the southern boundary of section 5, T. 73 S., R. 84 E.|
The Lone Jack prospect has a tunnel at an elevation of about 400 feet; large quartz boulders are on the dump (Roehm, 1938 [PE 119-8]. Between about 300 and 400 feet elevation, 2 parallel quartz veins in diorite are exposed for about 500 feet along a creek. Large masses of pyrite are scattered in the veins. Assays showed less than $1 per ton each in gold and silver. Maas and others (1995) collected several samples of quartz with minor pyrite and chalcopyrite that contained 20 to 1,850 parts per billion gold, 0.4 to 10.8 parts per million (ppm) silver, and 30 to 2,516 ppm copper.The rocks in the vicinity of this prospect are part of a large granodiorite-quartz diorite stock (Sainsbury, 1961; Eberlein and others, 1983; Brew, 1996). Early workers considered the stock to be Mesozoic or Cretaceous, but recent radiometric dating indicates that it is Devonian (S.M. Karl, oral communication, 2003).
|Geologic map unit||(-132.680541157897, 55.5630272492372)|
|Mineral deposit model||Polymetallic vein (Cox and Singer, 1986; model 22c).|
|Mineral deposit model number||22c|
|Age of mineralization||Unknown, other than that the veins are in Devonian granitic rocks.|
|Workings or exploration||At least one short adit.|
|Indication of production||None|
Additional commentsThis prospect is in the Karta River Wilderness Area, which is closed to exploration and mining.
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.
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.
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.
Roehm, J.C., 1938, Preliminary report of Lone Jack prospect, Karta Bay, Prince of Wales Island, Alaska: Alaska Territorial Department of Mines Property Examination 119-8, 2 p.
|Reporters||D.J. Grybeck (Applied Geology)|
|Last report date||5/1/2004|