|Quadrangle map, 1:250,000-scale||DE|
|Quadrangle map, 1:63,360-scale||C-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence, which was first sampled and described by Maas and others (1991), is near the tip of a small peninsula that juts out on the north side of Security Cove just inside its entrance. It is near the center of the east boundary of the NE1/4 section 21, T 82 S., R. 84 E.|
Geologic descriptionThe rocks in the vicinity of this occurrence are pre-Ordovician basaltic metavolcanic rocks, dacitic metavolcanic rocks, phyllite, and marble (Gehrels, 1991). As described by Maas and others (1991), the occurrence is a 20-foot zone with thin layers of pyrite 0.1 to 0.5 foot thick, interbedded with marble and chlorite schist. Their best sample across a 0.5-foot-thick layer of pyrite contained 357 parts per billion gold, 6.3 parts per million (ppm) silver, 2,885 ppm zinc, 1,103 ppm arsenic, and 2.3 percent barite. The pyrite layers apparently do not continue to the south across Security Cove.
|Geologic map unit||(-132.859762971415, 54.7469555679066)|
|Mineral deposit model||Probably a Kuroko massive-sulfide-type deposit (Cox and Singer, 1986; model 28a).|
|Mineral deposit model number||28a|
|Age of mineralization||Probably contemporaneous with the pre-Ordovician host rocks.|
|Workings or exploration||Only sampling by government geologists.|
|Indication of production||None|
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.
|Reporters||D.J. Grybeck (Applied Geology)|
|Last report date||9/1/2003|