|Quadrangle map, 1:250,000-scale||TK|
|Quadrangle map, 1:63,360-scale||B-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This placer prospect extends for about 2 miles of Granite Creek above its mouth on the Oshetna River (Csejtey and Miller, 1978, location 57). The placer is centered on Granite Creek at an elevation of about 4,300 feet. The location is accurate to within 1/4 mile.|
Geologic descriptionGold in Granite Creek occurs in Tertiary(?) alluvial gravel deposits. The prospect was discovered in 1914, when placer claims were located on lower Granite Creek. Enough gold was found to encourage further prospecting in 1918 (Chapin, 1918). The placer deposits overlie Tertiary volcanic rocks and Jurassic volcanic rocks, and sandstone and argillite of the Talkeetna Formation (Csejtey and others, 1978). A Jurassic intrusion crops out at the head of the creek. Quaternary glacial deposits are also present at the head of the creek. The stream valley is 50 to 250 feet wide and the alluvial gravel is up to 15 feet thick. Boulders are up to 10 feet in diameter. The creek gradient is 150 to 300 feet per mile. A U.S. Bureau of Mines sample of the gravel contains 0.0002 ounce of gold per cubic yard; other samples contain up to 329 parts per million zinc (Kurtak and others, 1992).
|Geologic map unit||(-147.864785400826, 62.2969306611224)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a)|
|Mineral deposit model number||39a|
|Age of mineralization||Tertiary(?) placer.|
|Workings or exploration||The prospect was discovered in 1914, when placer claims were located on lower Granite Creek. Enough gold was found to encourage further prospecting in 1918 (Chapin, 1918). Limited sampling by the U.S. Bureau of Mines (Kurtak and others, 1992).|
|Indication of production||Undetermined|
|Reserve estimates||An estimated 500,000 cubic yards of potentially auriferous alluvial material is present in the drainage but no estimate of grade has been made (Kurtak and others, 1992).|
|Production notes||No production is known.|
Additional commentsMAS/MILS number 20760020.
Chapin, Theodore, 1915, Auriferous gravels of the Nelchina-Susitna region: U.S. Geological Survey Bulletin 622-D, p. 118-130.
Chapin, Theodore, 1918, The Nelchina-Susitna region, Alaska: U.S. Geological Survey Bulletin 668, 67 p.
Cobb, E.H., 1972, Metallic mineral resources map of the Talkeetna Mountains quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-370, 1 sheet, scale 1:250,000.
Cobb, E.H., and Csejtey, Bela, Jr., 1980, Summaries of data on and lists of references to metallic and selected nonmetallic mineral deposits in the Talkeetna Mountains quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-716, 63 p.
Csejtey, Bela, Jr., and Miller, R.J., 1978, Map and table describing metalliferous and selected nonmetalliferous mineral deposits in the Talkeetna Mountains quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-558-B, 22 p., 1 sheet, scale 1:250,000.
Csejtey, Bela, Jr., Nelson, W.H., Jones, D.L., Silberling, N.J., Dean, R.M., Morris, M.S., Lanphere, M.A., Smith, J.G., and Silberman, M.L, 1978, Reconnaissance geologic map and geochronology, Talkeetna Mountains quadrangle, northern part of Anchorage quadrangle, and southwest part of Healy quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-558-A, 60 p., 1 sheet, scale 1:250,000.
Kurtak, J.M., Southworth, D.D., Balen, M.D., and Clautice, K.H., 1991, Mineral investigations in the Valdez Creek Mining District, south-central Alaska: U.S. Bureau of Mines Open-File Report 1-92, 658 p., 2 sheets, scale 1:250,000.
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.
|Reporters||R.K. Rogers (U. S. Geological Survey contractor)|
|Last report date||10/2/2002|