|Quadrangle map, 1:250,000-scale||MD|
|Quadrangle map, 1:63,360-scale||A-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Crystal Gulch placer deposit is in a steep, southerly-facing, first order gulch located at 900 feet (274 m) in Section 13, T. 26 S., R. 21 E., of the Kateel River Meridian. Location is accurate to within 100 feet (30 m).|
Geologic descriptionThe rich Crystal Gulch placer deposit occurs in a steep first order tributary of Ruby Creek. Stream gradient averages about 500 feet per mile (650 m/km). Most of the values occurred at the intersection of the gulch with Ruby Creek. The Crystal Gulch deposit was exhausted by 1924. The uranium mineral brookite was identified by Mertie (1936). Concentrates averaged 5 percent cassiterite during the life of the operation. (Ted Almasy, personal communication, 1998). Age of mineralization is unknown, but judged to be Quaternary, based on comparative geomorphological features in southwest Alaska (Bundtzen and Miller, 1997).
|Geologic map unit||(-154.782324549601, 63.2333922244188)|
|Mineral deposit model||Placer Au-PGE (Cox and Singer, 1986; model 39c).|
|Mineral deposit model number||39c|
|Workings or exploration||The placer deposit was mined exclusively by surface-hydraulic methods (Brown, 1926; Mertie, 1936).|
|Indication of production||Yes; small|
|Production notes||Production estimates are lumped with other properties on Ruby Creek, which produced a total of 1,511 ounces (47 kg) of gold prior to 1942.|
Additional commentsSee also Ruby-Strand (MD069), Birch Gulch (MD073), Holmes Gulch (MD0 72), Encio Gulch (MD063) and Upper Ruby Creek (MD068).
Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 242-286.
Cobb, E.H., 1978, Summary of references to mineral occurrences in the Beaver, Bettles, and Medfra quadrangles: U.S. Geological Survey Open File Report 78-94, 54 pages.
|Reporters||Bundtzen, T.K. (Pacific Rim Geological Consulting)|
|Last report date||6/7/1998|