|Quadrangle map, 1:250,000-scale||SO|
|Quadrangle map, 1:63,360-scale||D-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Big Four Creek is a major south tributary to the Casadepaga River. The mouth of Big Four Creek is at an elevation of 190 feet, 5 miles upstream of the confluence of the Casadepaga and Niukluk Rivers. Mining took place 0.5 mile upstream of the mouth of Big Four Creek. This is locality 68 of Cobb (1972, MF 445; 1978, OF 78-181).|
Geologic descriptionMining on Big Four Creek took place 0.5 mile upstream of the creek's mouth where it crosses a terrace of the Casadepaga River. Bedrock was not encountered during mining and the gold was on the surface and on clay layers in fine creek gravels. Gold values were apparently better near the surface than at depth on clay layers (Smith, 1910).
|Geologic map unit||(-164.175620825042, 64.9022623611366)|
|Mineral deposit model||Placer Au-PGE (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary; the numerous incised terraces along the Casadepaga River indicate that more than one cycle of erosion and deposition has developed placer deposits in the area. The low elevations between 170 to 270 feet along the first 11 miles of the river, suggest that Quaternary sea level fluctuations could have influenced placer development.|
|Workings or exploration||Small-scale surface placer mining by one person in 1907 (Smith, 1910).|
|Indication of production||Yes; small|
Cobb, E.H., 1972, Metallic mineral resources map of the Solomon quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-445, 1 sheet, scale 1:250,000.
Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Solomon quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-181, 185 p.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||8/19/1999|