|Quadrangle map, 1:250,000-scale||KC|
|Quadrangle map, 1:63,360-scale||A-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This site represents 3 occurrences along about 0.3 mile of shoreline at and near Driest Point (section 19, T. 77 S., R. 92 E., of the Copper River Meridian). The map site is at Driest Point and is accurate within 0.1 mile. The site corresponds to loc. 15 in Berg (1972 [I 684]), loc. 134 in Elliott and others (1978), and loc. 22a-c in Karl (1992).|
The country rocks at this site consist of sheared, recrystallized, Upper Triassic carbonate and clastic rocks, rhyolite, and basalt; and of diorite dikes that intrude the Triassic strata (Berg, 1972). The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time.
The mineral occurrences are quartz-calcite-barite-galena fissure veins up to 6 feet thick in sheared, rhyolite-clast conglomerate Berg, 1992; Karl, 1992). Quartz-calcite veins also cut pyritic diorite dikes that intrude the bedded rocks. Samples of variously mineralized bedded rocks contained up to 1.5 ppm Ag, 150 ppm Pb, 200 ppm Zn, and 5000 ppm Ba; a sample of the diorite contained 100 ppm Co, 700 ppm Cr, and 150 ppm Ni; and samples of mineralized rhyolite contained up to 0.7 ppm Ag (Karl, 1992, loc. 22a-c).The fissure veins are probably Late Cretaceous or younger, assuming that they formed during, or following, the regional metamorphism.
|Geologic map unit||(-131.60668007017, 55.176655248915)|
|Mineral deposit model||Polymetallic veins (Cox and Singer, 1986; model 22c)|
|Mineral deposit model number||22c|
|Age of mineralization||The fissure veins are probably Late Cretaceous or younger in age, assuming that they formed during, or following, the regional metamorphism.|
|Indication of production||None|
Berg, H.C., 1972, Geologic map of Annette Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-684, 8 p., 1 sheet, scale 1:63,360.
|Reporters||H.C. Berg, USGS|
|Last report date||7/6/1999|