|Quadrangle map, 1:250,000-scale||CH|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is at the head of Dennys Gulch at an elevation of about 2,950 feet, near the center of section 32, T. 30 N., R. 7 W.|
This record describes the lode deposit at the head of the Dennys Gulch. Both this lode prospect and a placer mine (CH019) in Dennys Gulch are associated with Denny O'Keefe, who had claims and explored the area from 1948 to 1957; much of the work on the lode and placer probably coincided (Kurtak and others, 2002). A magnetometer survey was run over Dennys Gulch and Sawlog Creek in 1951 (Williams, 1952); there was uranium exploration by the U.S. Geological Survey in 1956 (Freeman, 1963); 6 lode claims were staked in 1955 (Heiner and Wolff, 1968); and WGM Inc. explored in the area from 1975 to 1976, and in 1983 (Dashevsky, 1986).The rocks in Dennys Gulch are mainly Devonian quartz-mica schist and schistose quartzite intercalated with beds of greenschist and greenstone; the mineralization is associated with a thrust fault separating graphitic schist and quartz-muscovite schist. As described by Kurtak and others (2002), the rocks in upper Dennys Gulch are intensely stained dark red and are cut by numerous thin quartz veins. None of their samples of the quartz veins contained significant metal values, but there were reports that gold 'colors' could be panned 'at will' in the altered, quartz-veined rocks. Native iron is common in small, bright fragments, green copper staining is present, and the bitter taste of the water in the stream is attributed to arsenic. A panned-concentrate sample collected in the upper part of Dennys Gulch contained 235 parts per million (ppm) gold, 21.2 ppm silver, 133 ppm lead, 222 ppm zinc, and 116 ppm barite. Some of the rocks read as much as 0.035 milliroentgens per hour; these values are anomalous but probably do not indicate a body of economic uranium ore (Freeman, 1963).
|Geologic map unit||(-149.158128825226, 67.3793931738728)|
|Mineral deposit model||Unclear.|
|Alteration of deposit||Schist in upper Dennys Gulch is intensely stained dark red.|
|Workings or exploration||Both this lode prospect and a placer mine (CH019) in Dennys Gulch are associated with Denny O'Keefe, who had claims and explored the area from 1948 to 1957; much of the work on the lode and placer probably coincided (Kurtak and others, 2002). A magnetometer survey was run over Dennys Gulch and Sawlog Creek in 1951 (Williams, 1952); there was uranium exploration by the U.S. Geological Survey in 1956 (Freeman, 1963); 6 lode claims were staked in 1955 (Heiner and Wolff, 1968); and WGM Inc. explored in the area from 1975 to 1976, and in 1983 (Dashevsky, 1986).|
|Indication of production||None|
See also Dennys Gulch (CH019) and Sawlog Creek (CH020).MAS No. 0020310035
Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Chandalar and Wiseman quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-340, 205 p.
Cobb, E.H., 1977, Placer deposit map of central Alaska: U.S. Geological Survey Open-File Report 77-168-B, 64 p., 1 map, scale 1:1,000,000.
Dashevsky, S.S., 1986, Mines, prospect, and geochemical anomalies on Doyon Ltd. regional overselection lands Alaska, Block 1 - 8, v. 1 or II: Unpublished report for Doyon Ltd., 42 p. (on file at Doyon Ltd., Fairbanks, Alaska).
DeYoung, J.H., Jr., 1978, Mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-B, 2 sheets, scale 1:250,000.
Eakins, G.R., 1969, Uranium in Alaska: Alaska Division of Mines and Geology Geologic Report 38, 49 p., 2 sheets (scale 1:3,800,000).
Freeman, V.L., 1963, Examination of uranium prospects, 1956, in Contributions to economic geology of Alaska: U.S. Geological Survey Bulletin 1155, p. 29-33.
Heiner, L.E., and Wolff, E.N., eds., 1968, Mineral resources of northern Alaska, Final report, submitted to the NORTH Commission: University of Alaska, Mineral Industry Research Laboratory Report No. 16, 306 p.
Holdsworth, P.R., 1952, Report of the Commissioner of Mines for the Biennium ended December 31, 1952: Alaska Territorial Department of Mines Annual Report 1952, 66 p.
Holdsworth, P.R., 1955, Report of the Commissioner of Mines for the biennium ended December 31, 1954: Alaska Territorial Department of Mines Annual Report 1954, 110 p.
Kurtak, J.M., Klieforth, R.F., Clark, J.M., and Maclean, E.A., 2002, Mineral investigations in the Koyukuk mining district, northern Alaska, 2 vols.: Bureau of Land Management, Alaska Technical Report 50, 845 p.
|Reporters||J.M. Britton (Anchorage, Alaska); D.J. Grybeck (Contractor, U.S. Geological Survey)|
|Last report date||4/18/2010|