|Quadrangle map, 1:250,000-scale||SR|
|Quadrangle map, 1:63,360-scale||D-7|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This record describes an unnamed prospect in the Downing mine area (see additional comments). The map site is at an elevation of 2,700 feet, on the north valley wall of upper Bonanza Creek. It is in the SE1/4 section 31, T. 9 N., R. 1 W., of the Seward Meridian. The unnamed prospect is located east of the Francisco (SR017), Bonanza (SR018), and Whistler (SR020) prospects (also called Downing mine). This is location 18 of Cobb and Tysdal (1980). This location is accurate to within a quarter of a mile.|
The deposit at this prospect consists of auriferous, arsenopyrite-bearing quartz-calcite veins that heal fractures in a 5-foot-wide, Eocene(?) felsic dike locally called the Kenai Star dike. The dike strikes N30E and dips 45-60E (Tuck, 1933) and intrudes slate and sandstone of the Valdez Group of Late Cretaceous age (Nelson and others, 1985). Sericitic alteration envelopes, 0.4 to 0.8 inch wide, surround tiny fractures cutting the slate and sandstone country rock, but there is little alteration near the larger quartz veins in the dike (Mitchell, 1979).Hoekzema and Sherman (1983) refer to this prospect briefly under the name Downing mine (SR017), as a fractured dike occurs nearby.
|Geologic map unit||(-149.513662762867, 60.8202313024007)|
|Mineral deposit model||Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)|
|Mineral deposit model number||36a|
|Age of mineralization||Eocene(?) or younger; the veins heal fractures in the dike.|
|Alteration of deposit||Sericitic alteration envelopes 0.4 to 0.8 inch wide surround tiny fractures cutting slate and sandstone country rock, but little alteration is present near the larger quartz veins in the dike (Mitchell, 1979).|
|Workings or exploration||Tuck (1933) reported a 20-foot adit that exposed a 3-foot width of dike containing about 2 percent quartz veinlets carrying a small amount of arsenopyrite. A sample across the face contained only a trace of gold (Tuck, 1933). Mitchell (1979) visited the property in 1977 and reported 69 feet of workings. The U.S. Bureau of Mines visited the nearby Downing mine in 1982, but did not sample the prospect described in this record (Hoekzema and Sherman, 1983). Tuck (1933) wrote that nowhere on the Kenai Star dike was there observed anything that might be considered ore.|
|Indication of production||Undetermined|
|Production notes||The U.S. Bureau of Mines reported production of 150 ounces of gold from the Downing mine, which presumably included any production from the Francisco, Bonanza, and Whistler properties (Jansons and others, 1984). None of the production is believed to have come from the prospect described in this record.|
Additional commentsIn his description of this deposit, Tuck (1933) included references to the Francisco (SR017), Whistler (SR020), and Bonanza (SR018) properties on Bonanza Creek. This unnamed prospect is east of those properties that are collectively known as the Downing mine (Jansons and others, 1984).
Cobb, E.H., and Richter, D.H., 1972, Metallic mineral resources map of the Seward quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-466, 2 sheets, scale 1:250,000.
Cobb, E.H., and Tysdal, R.G., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Blying Sound and Seward quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-621, 276 p.
Hoekzema, R.P., and Sherman, G.E., 1983, Mineral investigations in the Chugach National Forest, Alaska (Peninsula study area): U.S. Bureau of Mines in-house report; held at U.S. Bureau of Land Management Alaska State Office, Anchorage, 524 p.
Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, southcentral Alaska: U.S. Bureau of Mines Mineral Land Assessment 5-84, 218 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.
Mitchell, P.A., 1979, Geology of the Hope-Sunrise (gold) mining district, north-central Kenai Peninsula, Alaska: Stanford University Master of Science thesis, 123 p.
Nelson, S.W., Dumoulin, J. A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645-B, 16 p., 1 sheet, scale 1:250,000.
Tuck, Ralph, 1933, The Moose Pass-Hope district, Kenai Peninsula, Alaska: U.S. Geological Survey Bulletin 849-I, p. 469-530.
|Reporters||Jeff A. Huber (Anchorage)|
|Last report date||2/20/2000|