|Quadrangle map, 1:250,000-scale||RB|
|Quadrangle map, 1:63,360-scale||C-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Cox Gulch is a south-flowing tributary of Big Creek, about 1 1/2 miles north-northwest of Boston Dome and 5 miles south-southeast of Ruby. Cox Gulch is not marked on the USGS Ruby (C-5) Quadrangle (1952, minor revisions in 1973) but was taken from location 5 of Cobb (1972 [MF-405]), and location 13 of Eberlein and others (1977). The coordinates mark the location of mining activity in section 34, T. 9 S., R. 17 E. The location is accurate.|
Geologic descriptionThe bedrock underlying Cox Gulch is Paleozoic phyllite and quartzite (Puchner and others, 1998). The placer ground along Cox Gulch is overlain by 15 feet of muck and 15 feet of gravel (Chapman and others, 1963). The creek was mined and prospected for tin in 1927. Intermittent work continued into the 1940s (Cobb and Chapman, 1981). The pay streak is about 30 feet wide and 1,000 feet long. The gold is generally rough and accompanied by the presence of cassiterite. The associated gravels are subangular. Tourmaline is found in some quartz pebbles. The placer material is probably not far removed from its source (Chapman and others, 1963). Where mined, the creek yielded 0.02 ounces of gold and 0.2-0.33 pounds of cassiterite per square foot of bedrock (Eberlein and others, 1977). At least 2,100 pounds of cassiterite concentrate are stockpiled at the site; there is no record of it being sold (Chapman and others, 1963).
|Geologic map unit||(-155.435402856063, 64.6612683297627)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary?|
|Workings or exploration||Cox Gulch was mined by surface methods between 1927 and the 1940s.|
|Indication of production||Yes; small|
|Production notes||At least 2,100 pounds of cassiterite were saved at the site. Production figures for gold are not available.|
Chapman, R.M., Coats, R.R., and Payne, T.G., 1963, Placer tin deposits in central Alaska: U.S. Geological Survey Open-File Report 239, 53 p.
Cobb, E.H., 1972, Metallic mineral resources map of the Ruby quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-405, 1 sheet, scale 1:250,000.
Cobb, E.H., and Chapman, R.M., 1981, Mineral occurrences (other than mineral fuels and construction materials) in the Kantishna River and Ruby quadrangles, Alaska: U.S. Geological Survey Open-File Report 81-170, 94 p.
Eberlein, G.D., Chapman, R.M., Foster, H.L., and Gassaway, J.S., 1977, Map and table describing known metalliferous and selected nonmetalliferous mineral deposits in central Alaska: U.S. Geological Survey Open-File Report 77-168-D, 132 p., 1 sheet, scale 1:1,000,000.
|Reporters||C.E. Cameron (Alaska Division of Geological and Geophysical Surveys)|
|Last report date||3/22/2000|