|Quadrangle map, 1:250,000-scale||SD|
|Quadrangle map, 1:63,360-scale||C-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Bluebird prospect is at an elevation of about 480 feet, about 0.2 mile southeast of the north end of Taylor Lake and near the center of section 21, T. 49 S., R. 75 E.|
Geologic descriptionThe Bluebird claim was located in 1903 on a quartz vein 2 feet thick. The only workings on the prospect are an open cut about 5 feet by 5 feet in size on the bank of a creek and a flooded shaft about 180 feet east-southeast of the open cut (Kimble and others, 1984). The open cut exposes a 1.6-foot- thick quartz vein that strikes N40W and dips 70SW in calcareous schist that strikes N22W and dips 70SW. There is abundant pyrite, sphalerite, chalcopyrite, and galena in the hanging wall of the vein. A 1.5-foot-long channel sample across the vein contained 17.1 parts per million (ppm) silver, 20 ppm gold, 2,000 ppm lead, and 1,300 ppm zinc. A 0.3-foot channel sample through the sulfide-rich hanging wall contained 296.5 ppm silver, 2.1 ppm gold, 1,300 ppm copper, 3,300 ppm lead, and 2,900 ppm zinc. The shaft does not expose mineralization but the size of its dump indicates about 400 feet of underground workings. A select sample of quartz-rich material from the dump contained 3 ppm silver, 400 ppm copper, 840 ppm lead, and 2,800 ppm zinc. The rocks in the area are part of the Cretaceous green schist unit of Brew and Grybeck (1984).
|Geologic map unit||(-133.385819321856, 57.6066892326362)|
|Mineral deposit model||Polymetallic vein (Cox and Singer, 1986; model 22c).|
|Mineral deposit model number||22c|
|Age of mineralization||Cretaceous or younger based on the age of the host rocks.|
|Workings or exploration||The prospect was explored by a small open cut and a flooded shaft that had about 400 feet of underground workings.|
|Indication of production||None|
Additional commentsThe prospect is in the Chuck River Wilderness Area which is closed to mineral exploration and mining.
Brew, D.A., and Grybeck, Donald, 1984, Geology of the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska, in U.S. Geological Survey and U.S. Bureau of Mines, Mineral resources of the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska: U.S. Geological Survey Bulletin, 1525, p. 19-52.
Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Sumdum and Taku River quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-698, 64 p.
Kimble, A.L., Still, J.C., and Rataj, J.L., 1984, Mineral deposits and occurrences in the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska, in U.S. Geological Survey and U.S. Bureau of Mines, Mineral resources of the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska: U.S. Geological Survey Bulletin 1525, p. 105-210.
|Reporters||Donald Grybeck (U.S. Geological Survey)|
|Last report date||10/8/2004|