|Quadrangle map, 1:250,000-scale||ID|
|Quadrangle map, 1:63,360-scale||A-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Quartz Gulch is a west-flowing stream that empties into Donlin Creek above Snow Gulch (ID166). The coordinates are near the mouth of Quartz Gulch at the site of the placer mining. The deposit is at an elevation of about 500 feet, about 0.2 mile southwest of the center of section 13, T. 23 N., R. 49 W., of the Seward Meridian. The location is accurate. The Quartz Gulch placer mine is locality 21 of Cobb (1972 [MF 363]); also described in Cobb (1976 [OFR 76-576]).|
The Quartz Gulch Mine is a placer deposit near the mouth of Quartz Gulch. The gold-bearing gravels in Quartz Gulch are restricted to an 2,500-foot-section of the gulch that intersects the ancestral, Late Tertiary terrace along the south side of Donlin Creek. According to Cady and others (1955) and Bundtzen and Miller (1997), Donlin Creek originally flowed northeast into the Iditarod River basin. After regional tilting, the drainage reversed and Donlin flowed into the Kuskokwim River basin. After the reversal, low grade gold placers in the Donlin Bench (ID162) were reconcentrated along Quartz Gulch, locally upgrading them to a commercial deposit. The gravel in Quartz Gulch varies from 10 to 50 feet thick and the gold is irregularly distributed on the bedrock (Cobb, 1974; Cobb, 1976 [OFR 76-576]). In addition to gold, the principle heavy minerals identified in placer concentrates are gold-bearing arsenopyrite, cassiterite, cinnabar, monazite, scheelite, stibnite and garnet. The rocks in vicinity of Quartz Gulch are mainly sandstone and shale of the Upper Cretaceous, Kuskokwim Group (Miller and Bundtzen, 1994; Bundtzen and Miller, 1997; Miller, Bundtzen, and Gray, 2005).Unpublished mint records indicate that Quartz Gulch produced at least 1,968 ounces of gold and 14 ounces of silver from 1911 to 1914. Later production is included with that of the Donlin Bench (ID162).
|Geologic map unit||(-158.184070572233, 62.0802977759819)|
|Mineral deposit model||Placer Au deposit (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||The alluvium in modern Quartz Gulch is probably Quaternary; the ancestral terrace is probably Late Tertiary.|
|Workings or exploration||Placer gold was found on Quartz Gulch in 1909 and production began in 1910 (Maddren, 1911). From 1910 to 1914, all of the mining and exploration activities in the area of Donlin Creek were mainly on Quartz, Snow, and Ruby Gulches (Maddren, 1915). In 1912, $29,000 in gold was mined on the No. 1 claim on Quartz Gulch. Most of this was produced in the summer from open cuts in gravel about 6 feet deep; the remainder was produced in the winter from drift mines that worked gravel 20 to 24 feet thick. Only about $6,000 more was mined in 1913 and 1914. Some mining continued to 1940, mainly in open cuts (Cobb, 1974).|
|Indication of production||Yes; small|
|Production notes||From 1911 to 1914, Quartz Gulch was the largest gold producer in the Donlin Creek district. Unpublished mint records indicate that production was at least 1,968 ounces of gold and 14.0 ounces of silver during that time. Later production is included with that of the Donlin Bench (ID162).|
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.
Cady, W.M., Wallace, R.E., Hoare, J.M., and Webber, E.J., 1955, The central Kuskokwim region, Alaska: U.S. Geological Survey Professional Paper 268, 132 p.
Cobb, E.H., 1972, Metallic mineral resources map of the Iditarod quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-363, 1 sheet, scale 1:250,000.
Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction material) in the Iditarod and Ophir quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-576, 101 p.
Maddren, A.G., 1911, Gold placer mining developments in the Innoko-Iditarod region: U.S. Geological Survey Bulletin 480-I, p. 236-270.
Maddren, A.G., 1915, Gold placers of the lower Kuskokwim, with a note on copper in the Russian Mountains: U.S. Geological Survey Bulletin 622-H, p. 292-360.
Miller, M.L., and Bundtzen, T.K., 1994, Generalized geologic map of the Iditarod quadrangle, Alaska showing potassium-argon, major oxide, trace element, fossil, paleocurrent, and archeological sample localities: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-A, 48 pages; 1 sheet, scale 1:250,000.
|Reporters||T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.), M.L. Miller (U.S. Geological Survey); and C.C. Hawley (Hawley Resource Group)|
|Last report date||5/26/2003|