|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-North occurrence is located near a 4,955 foot (1,510 m) summit about 6 kilometers east of Sheep Creek. The reporter visited the site in 1980.|
The Tin Creek-North occurrence consists of thin, 5 to 20 centimeter thick mineral veins containing johansenite, garnet, sphalerite (marmatite), and chalcopyrite in argillaceous limestone of the mid-Silurian Terra Cotta Mountains Sandstone a unit of the Dillinger subterrane (Bundtzen, Harris, and Gilbert, 1997).The mineralization is hosted within a thermally altered zone where prograde garnet-johansenite veins are cut by epidote replacement bodies that are accompanied by sulfide minerals. The sulfide skarns are near a 29 Ma granodiorite dike which is part of a larger, 5 kilometer wide, N70W-trending dike swarm which intrudes the Dillinger subterrane. One grab sample contained 2.25 percent copper, 1.21 percent lead, 0.11 percent zinc, 0.13 percent cadmium, and 319.8 grams/tonne silver (Bundtzen, Kline, and Clough, 1982; Szumigala, 1987).
|Geologic map unit||(-153.69622745481, 62.4543938181233)|
|Mineral deposit model||Copper-iron skarn (Cox and Singer, 1986; model 18b).|
|Mineral deposit model number||18b|
|Age of mineralization||Inferred to be 29 Ma, based on age date from nearby granodiorite dike (Solie and others, 1991).|
|Alteration of deposit||Epidotization.|
|Workings or exploration||The Tin Creek-North occurrence was first described in Bundtzen, Kline, and Clough (1982). One grab sample contained 2.25 percent copper, 1.21 percent lead, 0.11 percent zinc, 0.13 percent cadmium, and 319.8 grams/tonne silver (Bundtzen, Kline, and Clough, 1982; Szumigala, 1987).|
|Indication of production||None|
Additional commentsSee MG042, Tin Creek-Midway (MG043) and Tin Creek-South (MG046) prospects.
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.
|Reporters||T.K. Bundtzen (Pacific Rim Geological Consulting)|
|Last report date||12/5/1998|