|Quadrangle map, 1:250,000-scale||KC|
|Quadrangle map, 1:63,360-scale||D-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is at sea level on the north side of Burroughs Bay, about 4.2 miles northwest of Pt. Whaley. The site is in section 11, T. 68 S., R. 91 E., of the Copper River Meridian. It corresponds to loc. 26 in Elliott and others (1978). The location is accurate within a few hundred feet.|
Geologic descriptionThe country rocks in the area of this prospect include a Cretaceous foliated quartz diorite batholith; metamorphic roof pendants in the batholith; and a Miocene granite and quartz porphyry stock and associated dikes that intrude the batholith and the metamorphic rocks (Berg and others, 1978, p. 12-13; Berg and others, 1988, p. 23). The outcrop area of the stock and associated dikes is about a square mile. The deposit is in the Miocene granite and quartz porphyry and consists of molybdenite-bearing quartz fissure veins and molybdenite coatings on fracture surfaces, and of veins and disseminations of pyrite (Berg and others, 1978, p. 12-13 and table 2). Analyses of several samples of molybdenite-bearing quartz porphyry dikes showed up to 100 ppm Mo and traces of U (Koch and Elliott, 1978 [OFR 78-156A]). The mineralogy, hostrock, age, and setting indicate that this is a porphyry molybdenum deposit similar in type and origin to the much larger one at Quartz Hill (KC105).
|Geologic map unit||(-131.298698609227, 55.9936330584942)|
|Mineral deposit model||Porphyry molybdenum, low-F (Cox and Singer, 1986; model 21b)|
|Mineral deposit model number||21b|
|Age of mineralization||Miocene.|
|Alteration of deposit||Pyritization and silicification.|
|Workings or exploration||The deposit has been examined by private interests, but none of their findings have been made public. A grade of 0.06% molybdenite has been reported (Eakins and others, 1983, p. 46).|
|Indication of production||None|
Additional commentsAlso see Quartz Hill (KC105).
Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map I-1807, 27 p., scale 1:250,000.
Berg, H.C., Elliott, R.L., Smith, J.G., Pittman, T.L., and Kimball, A. L., 1977, Mineral resources of the Granite Fiords Wilderness Study Area, Alaska, with a section on aeromagnetic data by Andrew Griscom: U.S. Geological Survey Bulletin 1403, 151 p.
Eakins, G.R., Bundtzen, T.K., Robinson, M.S., Clough, J.G., Green, C.B., Clautice, K.H., and Albanese M.A., 1983, Alaska's mineral industry, 1982: Alaska Division of Geological and Geophysical Surveys Special Report 31, 63 p.
Elliott, R.L., Berg, H.C., and Karl, S.M., 1978, map and table describing metalliferous and selected non-metalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-73-B, 17 p., 1 sheet, scale 1:250,000.
|Reporters||H.C. Berg, USGS|
|Last report date||6/29/1999|