|Quadrangle map, 1:250,000-scale||CR|
|Quadrangle map, 1:63,360-scale||B-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Lucky Monday prospect is about 0.2 mile east of the center of section 30, T. 75 S., R. 86 E. It is about 0. 3 mile east of the outlet of the small lake in the west half of that section.|
This prospect was found by Noranda Exploration, Inc. in 1978 (Maas and others 1991). The rocks in the area consist of a heterogeneous series of metavolcanic rocks, generally of rhyolite to latite composition, that are part of the Wales Group of Late Proterozoic and Cambrian age (Eberlein and others, 1983; Brew, 1996).The host rocks of the deposit are white to cream, metarhyolite that weathers orange and contains 1 to 2 percent pyrite. The best mineralization occurs at the base of a small waterfall, where several irregular layers and lenses of massive sulfides up to 5 inches thick are interbedded in the metarhyolite (D.J. Grybeck, unpublished field notes, 1985). The layers are mainly pyrite and sphalerite with minor chalcopyrite and galena. Selected samples of the massive sulfide layers contained 100 to 150 parts per million (ppm) silver, 0.2 to 1 percent copper, 20 to 50 ppm molybdenum, major zinc and lead, and 0.15 to 0.60 ppm gold. Similar rhyolite with thin massive sulfide lenses reportedly extends to the northwest at least as far as Polk Inlet, but the Lucky Monday deposit reportedly is the best mineralization found by industry in the area (William Block, oral communication, 1985). Maas and others (1991) collected 29 samples at or near this prospect; the best contained 51 parts per billion gold, 1.3 ppm silver, 171 ppm copper, 258 ppm lead, and 443 ppm zinc.
|Geologic map unit||(-132.398810901523, 55.3372200132186)|
|Mineral deposit model||Kuroko massive sulfide (Cox and Singer, 1986; model 28a).|
|Mineral deposit model number||28a|
|Age of mineralization||Deposit probably formed during the deposition of its Late Proterozoic or Cambrian host rocks.|
|Workings or exploration||A few prospect pits and other surface sampling of outcrops of mineralization.|
|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.
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.
|Reporters||D.J. Grybeck (Applied Geology)|
|Last report date||5/1/2004|