|Quadrangle map, 1:250,000-scale||MG|
|Quadrangle map, 1:63,360-scale||B-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Tin Creek-Tributary occurrence is located in a small, unnamed tributary gulch of Tin Creek at an elevation of approximately 2,800 feet (854 m) in the NE1/4 sec. 2, T. 27 N., R. 24 W., of the Seward Meridian. The location corresponds to mineral occurrence no. 2 of Cobb (1972), and is located to within 1,000 feet (305 m).|
At the Tin Creek-Tributary occurrence, chalcopyrite and other sulfides are localized within one foot of a malachite-stained shear zone that extends for about 6 meters along dip. The shear zone cuts calcareous clastics of the mid-Silurian Terra Cotta Mountains Sandstone, a unit of the Dillinger subterrane (Bundtzen, Harris, and Gilbert, 1997).Sulfide grab samples contain 0.70 percent copper and 0.15 percent zinc. Nearby stream cobbles contain pyrrhotite, with minor sphalerite and chalcopyrite. Placer concentrates contain anomalous copper and zinc in the nearby stream gulch that cuts the mineralized shear zone (Cobb, 1972).
|Geologic map unit||(-153.666228065808, 62.4623948331104)|
|Mineral deposit model||Polymetallic vein (Cox and Singer, 1986; model 22c).|
|Mineral deposit model number||22c|
|Workings or exploration||Sulfide grab samples contain up to 0.70 percent copper and 0.15 percent zinc. Nearby stream cobbles contain pyrrhotite and minor sphalerite. Placer concentrates contain anomalous copper and zinc in a stream gulch that cuts the mineralized area.|
|Indication of production||None|
Bundtzen, T.K., Harris, E.E., and Gilbert, W.G., 1997, Geologic Map of the eastern McGrath quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 97-14, 34 p., 1 sheet, scale 1:125,000.
Bundtzen, T.K., Kline, J.T., and Clough, J.G., 1982, Preliminary geologiy of the McGrath B-2 quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Open-File report 149, 22 p., 1 sheet, scale 1:40,000.
Cobb, E.H., 1972, Metallic mineral resources map of the McGrath quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-379, 1 sheet, 1:250,000 scale.
Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-485, 101 p.
MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous mineral deposits in the western part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-F, 38 p., 1 sheet, scale 1:1,000,000.
|Reporters||T.K. Bundtzen (Pacific Rim Geological Consulting)|
|Last report date||11/6/1998|