|Quadrangle map, 1:250,000-scale||MM|
|Quadrangle map, 1:63,360-scale||C-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Spruce Creek No. 1, or Ridgetop, prospect (Cobb, 1980 [OFR 80-263]) is at an elevation of about 4250 feet about 1600 feet west of Spruce Peak, on the divide between Crevice and Spruce creeks. The location is probably accurate within 250 feet. The prospect corresponds roughly to soil sample locality 242 of Hawley and Associates (1978), and to locality 62 of Bundtzen (1981). It probably is the same as occurrence 84 of Thornsberry, McKee, and Salisbury (1984), although they locate the prospect north of the divide.|
This deposit is a sulfide-bearing quartz vein in a shear zone in metafelsite of the lower Paleozoic Spruce Creek sequence. A fault that strikes NW cuts the metafelsite near the prospect, but whether the fault and the vein are related is uncertain (Bundtzen, 1981; Thornsberry, McKee, and Salisbury, 1984, fig. K-2).The prospect was first described by Davis (1923, p. 133), who called it the Ridgetop. He described the deposit as a 12-foot-wide lode that was iron- and copper-stained and contained 'a very little galena.' Wells (1933, p. 374-375) apparently called the prospect Spruce Creek No. 1, and described it as a 12-foot-thick pyritic quartz vein. When Well visited in 193l, the prospect pits were sloughed. No assays were given by either Davis or Wells. The prospect was examined by Hawley and Associates in 1976 (1978, samples 242 and 243), who collected two soil samples. Soil at the prospect (no. 242) contained 0.51 ppm gold and 3.2 ppm silver. Reddish residual soil about 400 feet from the prospect (no. 243) contained 1.2 ppm gold, 90 ppm silver, 485 ppm copper, 10500 ppm lead, and 7000 ppm zinc. Bundtzen (1981, locality 62) collected 5 mineralized rock samples that assayed 0.01 to 0.225 ounce of gold per ton, and up to 86 ppm molybdenum, 9.7 ppm uranium, and 14.7 ppm thorium.
|Geologic map unit||(-150.713484272468, 63.5812992624668)|
|Mineral deposit model||Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 36a).|
|Mineral deposit model number||36a|
|Age of mineralization||The deposit is assumed to be Eocene (see record MM091).|
|Alteration of deposit||Silicification. Oxidation of iron and copper minerals.|
|Workings or exploration||The prospect was explored by shallow pits dug before 1922 (Davis, 1923). There has been little additional work since then , but natural rubble crops of quartz vein material are widespread on the divide between Spruce and Crevice Creeks.|
|Indication of production||None|
Additional commentsThe prospect is in Denali National Park and Preserve.
Bundtzen, T.K., 1981, Geology and mineral deposits of the Kantishna Hills, Mt. McKinley quadrangle, Alaska: M. S. Thesis, University of Alaska, College, Alaska, 238 p.
Cobb, E.H., 1980, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mount McKinley quadrangle, Alaska: U. S. Geological Survey Open-File Report 80-363, 150 p.
Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: U.S. Geological Survey Bulletin 1693, 379 p.
Davis, J. A., 1923, The Kantishna region, Alaska, in Stewart, B. D., Annual Report of the Mine Inspector to the Governor of Alaska, 1922: Alaska Division of Geological and Geophysical Surveys AR-1922.
Hawley, C. C. and Associates, Inc, 1978, Mineral appraisal of lands adjacent to Mt. McKinley National Park, Alaska: U. S. Bureau of Mines Open-File Report 24-78, 275 p. (paged by sections).
Thornsberry, V. V., McKee, C. J., and Salisbury, W. G., eds, 1984, 1983 Mineral Resource Studies: Kantishna Hills and Dunkle Mine Areas, Denali National Park and Preserve, Alaska: U. S. Bureau of Mines Open-File Report 129-84. 3 Volumes: v. 1, Text; v. 2, Appendices; v. 3, Maps. Prepared by Salisbury & Dietz, Inc., Spokane, WA.
|Last report date||5/2/2001|