|Quadrangle map, 1:250,000-scale||MH|
|Quadrangle map, 1:63,360-scale||C-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This placer prospect is at an elevation of 2,700 on upper McCumber Creek in the NW1/4NE1/4 section 15, T. 14 S, R. 11 E., Fairbanks Meridian. It corresponds to locality 3 of Cobb (1979 [OFR 79-238]) and locality N2 in table 3 of Nokelberg and others (1991). The location is accurate within a mile.|
Geologic descriptionIn the McCumber Creek area small amounts of gold occur in alluvial gravel in streams draining an area of extensive glacial deposits (Smith, 1932). The gravel consists mainly of metasedimentary schists (Nokleberg and others, 1991). The most common bedrock types in the area are quartz-mica schist and quartz-rich phyllite; sulfide-bearing cobbles and quartz float are common (T. Hinderman, written communication, 1986). The schist is cut by diabase dikes and is overlain by conglomerate of the Nenana Gravel of Tertiary age, which is considered to be the source of placer gold in other districts in central Alaska (T. Hinderman, written communication, 1986). Gold recovered by T. Hinderman from Morningstar Creek in 1986 was flat and contained minor inclusions of silver. Most of the minerals accompanying the gold were garnet and magnetite.
|Geologic map unit||(-145.581485372527, 63.7057012165596)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Holocene.|
|Workings or exploration||Mining claims on McCumber Creek recorded in 1954 reportedly were idle in 1974 (Mulligan, 1974). In 1986 the McCumber Morningstar Property consisted of 40 State claims controlled by Richard Knudsen of Anchorage (T. Hinderman, written communication, 1986). A placer test completed in 1986 resulted in the owner allowing the claims to lapse. The test showed a resource in lower Morningstar Creek of 128,000 cubic yards of gravel grading $4.83 (0.019 ounce of gold) per cubic yard. McCumber Creek contains a much larger, lower-grade resource of 1,200,000 cubic yards of gravel grading $1.18 (0.0045 ounce of gold) per cubic yard.|
|Indication of production||Yes; small|
Brooks, A.H., 1913, Mineral resources of Alaska, report on progress of investigations in 1912: U.S. Geological Survey Bulletin 542, 308 p.
Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mount Hayes quadrangle, Alaska: U.S. Geological Survey Open-File Report 79-238, 140 p.
MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.
Moffit, F.H., 1942, Geology of the Gerstle River district, Alaska, with a report on the Black Rapids Glacier: U.S. Geological Survey Bulletin 926-B, p. 107-160.
Moffit, F.H., 1954, Geology of the eastern part of the Alaska Range and adjacent area: U.S. Geological Survey Bulletin 989-D, p. 65-218.
Mulligan, J.J., 1974, Mineral resources of the Trans-Alaska Pipeline corridor: U.S. Bureau of Mines Information Circular 8626, 24 p., 9 sheets, scale 1:250,000.
Nokleberg, W.J., Lange, I.M., Roback, R.C., Yeend, Warren, and Silva, S.R., 1991, Map showing locations of metalliferous lode and placer mineral occurrences, mineral deposits, prospects, and mines, Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-C, 42 p., 1 sheet, scale 1:250,000.
Smith, P.S., 1932, Mineral industry of Alaska in 1929, in Smith, P.S., and others Mineral resources of Alaska, report on progress of investigations in 1929: U.S. Geological Survey Bulletin 824-A, p. 1-81.
Smith, P.S., 1933, Mineral industry of Alaska in 1930: U.S. Geological Survey Bulletin 836-A, p. 1-83.
Smith, P.S., 1933, Mineral industry of Alaska in 1931: U.S. Geological Survey Bulletin 844-A, p. 1-81.
|Reporters||W.T. Ellis (Alaska Earth Science), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS)|
|Last report date||8/14/2002|