|Quadrangle map, 1:250,000-scale||RM|
|Quadrangle map, 1:63,360-scale||A-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Ophir Creek flows northwest to the Kuskokwim River from headwaters along the west side of Mount Hamilton. The map site is located on the creek in the SE/4 sec. 3, T. 13 N., R. 59 W., of the Seward Meridian. This is locality 16 of Hoare and Cobb (1972, 1977).|
Geologic descriptionMaddren (1915) reported that fine colors of gold were found along upper Ophir Creek as early as 1901-02, but serious prospecting did not start until 1913. The alluvial deposits along the upper 5 miles of the creek are coarse gravels that contain large cobbles and boulders. Farther downstream, the gravels become finer, and silt makes up a large part of the deposits. Alluvial fan deposits from tributary streams have been incised by Ophir Creek. The incised fan deposits are frozen, but the gravels of the present Ophir Creek floodplain are not. Prospect shafts as deep as 38 feet have been used to explore Ophir Creek, but the fine gold, although widespread along Ophir Creek and its tributaries, does not appear to be significantly concentrated. Mining has not been reported along Ophir Creek, but the entire upper drainage and its tributaries were once staked. Bedrock in upper Ophir Creek includes large areas of thermally metamorphosed Jurassic rocks along the northeast side of a large mid-Cretaceous granitic pluton (Box and others, 1993).
|Geologic map unit||(-159.848321415109, 61.2382697395057)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a)|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||Surface prospecting, sinking of shafts to depths of at least 38 feet, and some drilling and trenching have been done along Ophir Creek. The upper 10 miles of the creek and its tributaries have been staked.|
|Indication of production||None|
Box, S. E, Moll-Stalcup, E. J., Frost, T. P., and Murphy, J. M., 1993, Preliminary geologic map of the Bethel and southern Russian Mission quadrangles, southwestern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2226-A, 20 p., scale 1:250,000.
Hoare, J M., and Cobb, E.H., 1972, Metallic mineral resources map of the Russian Mission quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-444, 1 sheet, scale 1:250,000.
Hoare, J.M., and Cobb, E.H., 1977, Mineral occurrences (other than mineral fuels and construction materials) in the Bethel, Goodnews, and Russian Mission quadrangles, Alaska: U.S. Geological Survey Open-File Report 77-156, 98 p.
|Reporters||Travis L. Hudson and Madelyn A. Millholland|
|Last report date||6/10/2001|