|Quadrangle map, 1:250,000-scale||CR|
|Quadrangle map, 1:63,360-scale||A-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Gould prospect is near the south end of Sukkwan Island about 0.7 mile south of the south end of Sukkwan Lake. It is near the center of section 16, T. 79 S., R. 84 E.|
Geologic descriptionAs described by Chapin (1919), the Gould deposit is in schist near a granite contact. Chalcopyrite, pyrite, and pyrrhotite occur both in layers parallel to the foliation in the schist and in veinlets that crosscut the foliation. There was some surface exploration in 1917. The contact is between leucosyenite of early Permian or Late Pennsylvanian age and sedimentary rocks of the Descon Formation of Silurian and Ordovician age (Eberlein and others, 1983; Brew, 1996). This contact was examined by Maas and others (1991), and while they could not find the old workings, they did find occurrences of pyrite and pyrrhotite with chalcopyrite along a mile of the contact. The sulfides occur mainly along the layering in the sedimentary rocks. Several samples were taken along the contact; the highest values were 1,187 parts per million (ppm) zinc and 485 ppm copper.
|Geologic map unit||(-132.761798134764, 55.0187431854567)|
|Mineral deposit model||Unclear whether syngenetic or epigenetic.|
|Age of mineralization||Unclear whether the mineralization is related to the Silurian or Ordovician host rocks or to the adjacent Permian or Pennsylvanian leucosyenite.|
|Workings or exploration||There probably was some surface work done before 1919 but the workings could not be located in 1991.|
|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.
Chapin, Theodore, 1919, A molybdenite lode on Healy River: U.S. Geological Survey Bulletin 692, p. 329.
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.
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|