|Quadrangle map, 1:250,000-scale||CY|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Boulder Creek is a northwest-flowing tributary of Coal Creek. The coordinates given are for placers at the mouth of the creek, in the NE1/4 of section 3, T. 5 N., R. 22 E., of the Fairbanks Meridian. The creek is about 3 miles long and could have other placer production or exploration along its length. It is location 5 of Cobb (1972 [MF-390]). The location is accurate.|
The bedrock in the Boulder Creek drainage is composed of Cretaceous to Tertiary sedimentary rocks (Dover and Miyaoka, 1988). Placer gold in stream gravels was bright and flaky and had a fineness of 909.5 (National Park Service, 1990). The bench-placer gold is unevenly distributed and tarnished with manganese. Gold was found in the normal-fault contact zone between Tertiary conglomerate on the north and Permian conglomerate with quartz stockwork veins on the south (National Park Service, 1990).Claims were staked along Boulder Creek as early as 1908, and mining also began about then (National Park Service, 1990; Chapin, 1914). During 1935-36, small-scale drift mining took place along the creek. Placer mines were located near the mouth of the creek, but other locations along the creek may have been mined or prospected. By 1943, the creek had produced 88 troy ounces of gold and 11 troy ounces of silver. By 1951, 334 troy ounces of gold and 42 troy ounces of silver had been removed from the creek (National Park Service, 1990).
|Geologic map unit||(-143.019389408385, 65.28067056328)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a)|
|Mineral deposit model number||39a|
|Age of mineralization||Tertiary-Quaternary.|
|Workings or exploration||Mining along the creek began as early as 1908 and continued intermittently until at least 1951. There were both stream and bench placer mines and prospects (National Park Service, 1990).|
|Indication of production||Yes; small|
|Production notes||By 1943, the creek had produced 88 troy ounces of gold and 11 troy ounces of silver. By 1951, 334 troy ounces of gold and 42 troy ounces of silver had been removed from the creek (National Park Service, 1990).|
Additional commentsSee also Coal Creek (CY006) and Colorado Creek (CY007). This site is within the Yukon-Charley Rivers National Preserve.
Chapin, Theodore, 1914, Placer mining in the Yukon-Tanana region: U.S. Geological Survey Bulletin 592-J, p. 357-362.
Cobb, E.H., 1972, Metallic mineral resources map of the Charley River quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-390, 1 sheet, scale 1:250,000.
Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Charley River and Coleen quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-632, 45 p.
Dover, J.A., and Miyaoka, R.T., 1988, Reinterpreted geologic map and fossil data, Charley River quadrangle, east-central Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2004, 2 sheets, scale 1:250,000.
Mertie, J.B., Jr., 1938, Gold placers of the Fortymile, Eagle, and Circle districts, Alaska: U.S. Geological Survey Bulletin 897-C, p. 133-261.
Mertie, J.B., Jr., 1942, Tertiary deposits of the Eagle-Circle district, Alaska: U.S. Geological Survey Bulletin 917-D, p. 213-264.
National Park Service, 1990, Final environmental impact statement, volume 1, Mining in Yukon-Charley Rivers National Preserve, Alaska: National Park Service, Anchorage, Alaska, p. 36-44.
|Reporters||C.E. Cameron (ADGGS)|
|Last report date||4/7/2000|