|Quadrangle map, 1:250,000-scale||DE|
|Quadrangle map, 1:63,360-scale||D-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is at an elevation of about 720 feet about 0.6 mile west-southwest of the head of Vesta Bay. It is near the northwest corner of section 20, T. 80 S., R. 83 E. The location is probably on the four patented mining claim shown on current (2003) U.S. Forest Service maps. The location is accurate to within one-quarter mile.|
The Mount Vesta prospect was found before 1902 and was explored intermittently until at least 1906 by several open cuts and an adit 89 feet long (Brooks, 1902; Wright and Wright, 1905, 1906, 1908; Smith 1914). The rocks in the vicinity consist of pre-Ordovician marble to the west of a regionally-extensive normal fault, and mixed pre-Ordovician marble and metamorphosed dacitic rocks to the east of the fault (Gehrels, 1991). It is unclear which side of the fault the Mount Vesta prospect is on, but the host rocks at the prospect are mainly marble cut by a mafic dike.Maas and others (1991) mapped an 89-foot adit that follows an S-shaped vein 0.17 to 0.33 feet wide that has tetrahedrite, malachite, and calcite near the portal. Samples contained up to 25.95 ounces of silver per ton, 1.2 percent copper, 3.34 percent lead, 1.14 parts per million (ppm) gold, and more than 2,000 ppm bismuth and antimony. Other mineralized zones may be present. Wright and Wright (1906) mention the occurrence of chalcopyrite, galena, and sphalerite.
|Geologic map unit||(-132.948259461249, 54.9250534491103)|
|Mineral deposit model||Shear zone cuts marble and contains tetrahedrite, chalcopyrite, galena, and sphalerite.|
|Age of mineralization||Unknown, other than that the prospect is younger than the pre-Ordovician host rocks.|
|Alteration of deposit||Oxidization of copper minerals.|
|Workings or exploration||Developed by open cuts and an 89-foot adit by 1906. Probably no substantial work since.|
|Indication of production||None|
Additional commentsLocated on four patented mining claims. The adjacent lands in the area have been conveyed to the Sealaska Corporation or are under application.
Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 p.
Cobb, E. H., 1972, Metallic mineral resources of the Dixon Entrance quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-434, 1 sheet, scale 1:250,000.
Cobb, E. H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Dixon Entrance quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-863, 34 p.
Gehrels, G. E., 1991, Geologic map of Long Island and southern and central Dall Island, southeastern Alaska: U.S. Geological Survey Map MF-2146, 1 sheet, scale 1:63,360.
Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.
Maas, K.M., Still, J.C., Clough, A.H., and Oliver, L.K., 1991, Mineral investigations in the Ketchikan mining district, Alaska, 1990: southern Prince of Wales Island and vicinity: U.S. Bureau of Mines Open-File Report 33-91, 139 p., 12 sheets, scale 1:63,360.
Smith, P.S., 1914, Lode mining in the Ketchikan region, Alaska: U.S. Geological Survey Bulletin 592-B, p. 75-94.
Wedow, Helmuth, Jr., 1953, Preliminary summary of reconnaissance for uranium and thorium in Alaska, 1952: U.S. Geological Survey Circular 248, 15 p.
Wright, F.E., and Wright, C.W., 1905, Economic developments in southeastern Alaska, in Brooks, A.H., Report on Progress of Investigations of Mineral Resources of Alaska in 1904: U.S. Geological Survey Bulletin 259, p. 47-68.
Wright, F.E., and Wright, C.W., 1906, Lode mining in southeastern Alaska, in Brooks, A.H., 1906, Report on Progress of Investigations of Mineral Resources of Alaska in 1905: U.S. Geological Survey Bulletin 284, p. 30-54.
|Reporters||D.J. Grybeck (Applied Geology)|
|Last report date||9/1/2003|