|Quadrangle map, 1:250,000-scale||KC|
|Quadrangle map, 1:63,360-scale||B-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Baltic Star and Queen claims extend from the shore of Thorne Arm east-northeastward to an elevation of approximately 200 feet, about 0.3 mile west-southwest of the head of Star Lake The map site is in section 7, T. 75 S., R. 94 E., of the Copper River Meridian, about at the junction of the two claims, and is accurate within a few hundred feet. The site corresponds to loc. 88 in Elliott and others (1978), who, following an error in Wright and Wright (1908), erroneously call it 'Baltic/Queen.'|
The country rocks in this part of Revillagigedo Island are marine, interbedded, andesitic and basaltic metavolcanic rocks and subordinate pelitic metasedimentary rocks that are intruded by stocks, sills, and dikes of Cretaceous feldspar-porphyritic granodiorite (Berg and others, 1988). The strata and some of the granodiorite were regionally metamorphosed to greenschist grade in Late Cretaceous time. These regionally metamorphosed rocks subsequently were locally remetamorphosed to hornblende hornfels near the contacts of Cretaceous granodiorite plutons that were emplaced after the regional metamorphism. The premetamorphic age of the strata is uncertain. Berg and others (1988) assign them a Mesozoic or (late) Paleozoic age. Berg (1982) and Crawford and others (2000) assign them to the Gravina belt, of Late Jurassic or Cretaceous age, or to the Taku terrane, of late Paleozoic to Late Triassic age. The metamorphic and intrusive rocks locally are overlain by basalt and andesite lava flows of Quaternary or Tertiary age.The Baltic Star and Queen claims are on a quartz fissure vein that strikes generally eastward and dips steeply to vertically, across the foliation of the enclosing schist, which strikes N20W and dips 70NE (Wright and Wright, 1908, p. 148). The vein is 1-6 feet thick and contains small amounts of pyrite, sphalerite, and [probably] galena, along with low values in gold. The deposit was explored in the early 1900s by opencuts, two short prospect tunnels, and an inclined shaft 40 feet deep (Wright and Wright, 1908, p. 148). Maas and others (1995, p. 215) note that the quartz in the veins in this area is not recrystallized; the veins thus are probably younger than most or all of the Late Cretaceous regional metamorphism.
|Geologic map unit||(-131.193694214298, 55.3806597526802)|
|Mineral deposit model||Low-sulfide Au-quartz veins (Cox and singer, 1986; model 36a)|
|Mineral deposit model number||36a|
|Age of mineralization||Maas and others (1995, p. 215) note that the quartz in the veins in this area is not recrystallized; the veins thus are probably younger than most or all of the Late Cretaceous regional metamorphism.|
|Workings or exploration||The deposit was explored in the early 1900s by opencuts, two short prospect tunnels, and an inclined shaft 40 feet deep (Wright and Wright, 1908, p. 148).|
|Indication of production||None|
Additional commentsThe Baltic Star prospect was erroneously called 'Baltic' by Wright and Wright (1908, p. 148) and by Elliott and others (1978, loc. 88).
Berg, H.C., 1982, The Alaska Mineral Resource Assessment Program; guide to information about the geology and mineral resources of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Circular 855, 24 p.
Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map I-1807, 27 p., scale 1:250,000.
Crawford, M.L., Crawford, W.A., and Gehrels, G.E., 2000, Terrane assembly and structural relationships in the eastern Prince Rupert quadrangle, British Columbia, in H.H. Stowell and W.C.McClelland, eds., Tectonics of the Coast Mountains, southeastern Alaska and British Columbia: Geological Society of America Special Paper 343, p. 1-21.
Elliott, R.L., Berg, H.C., and Karl, S.M.,1978, Map and table describing metalliferous and selected non-metalliferous mineral deposits in the Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-73B, 17 p., 1 sheet, scale 1:250,000.
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.
|Reporters||H.C. Berg, USGS|
|Last report date||7/4/1999|