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Schoonover

Prospect, Probably inactive

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Alternative names

Porcupine Quartz No. 1

Commodities and mineralogy

Main commodities Au
Other commodities Cu; Pb; Zn
Ore minerals chalcopyrite; galena; gold; pyrite; sphalerite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-7
Latitude 60.2841
Longitude -149.4309
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is located near where Porcupine Creek turns from southeast to northeast flowing at an elevation of about 2,000 feet. It is situated in the center of the N1/2 section 10, T. 2 N., R. 1 W., of the Seward Meridian. This is location 82a of Cobb and Tysdal (1980) and location S-211 of Jansons and others (1984). This location is accurate to within 1,000 feet.

Geologic setting

Geologic description

This occurrence consists of 1- to 15-inch-wide quartz-calcite veins that average 3 inches wide, strike N70W, and dip 80NE. The veins contain chalcopyrite, galena, pyrite, sphalerite, and gold. One vein can be traced along strike for 125 feet (Jansons and others, 1984). The veins are hosted by north-south striking slate of the Valdez Group of Late Cretaceous age that dip to steeply to the east (Nelson and others, 1985).
Assays as much as $100 (gold value of $20.65 per ounce) have been obtained on samples from some of the larger veins (Johnson, 1912). Three samples collected in 1981 by the U.S. Bureau of Mines assayed from a trace to 0.25 ppm gold; other metal values, including copper, lead, and zinc, ranged from none detected to 89 ppm (Jansons and others, 1984).
Geologic map unit (-149.433054509171, 60.2835393287457)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Cretaceous or younger; the veins cut rocks of the Valdez Group of Late Cretaceous age.

Production and reserves

Workings or exploration Johnson (1912) reported an adit when he described the vein, but he gave no details about the adit. He also reported that assays as much as $100 of gold per ton of ore have been obtained (gold value of $20.65 per ounce). Three samples collected in 1981 by the U.S. Bureau of Mines assayed from a trace to 0.25 ppm gold; other metal values, including copper, lead, and zinc, ranged from none detected to 89 ppm (Jansons and others, 1984).
Indication of production None

Additional comments

Jansons and others (1984) described the site as being on Porcupine Creek at an elevation of 2,000 feet in the NW1/4 of section 10, T. 2 N., R. 1 W. Tysdal (1978 [MF-880-A]) also located the site in section 10, T. 2 N., R. 1 W., of the Seward Meridian. Both authors maps located the site on Porcupine Creek. Martin and others (1915) identified this creek as Porcupine Creek. The 1994 USGS B7 topographic map has labeled this creek Primrose Creek, but the USGS B7-SE topographic calls it Porcupine Creek.

References

MRDS Number A010522

References

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.
Johnson, B.L., 1912, Mineral resources of Alaska, report on progress of investigations in 1911--Gold deposits of the Seward-Sunrise region, Kenai Peninsula: U.S. Geological Survey Bulletin 520-E, p. 131-173.
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.
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.
Tysdal, R.G., 1978, Mines, prospects, and occurrences map of the Seward and Blying Sound quadrangles, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-880-A, 2 sheets, scale 1:250,000.
Reporters Jeff A. Huber and Carol S. Huber (Anchorage)
Last report date 3/9/1994