Unnamed (shoreline of Sylburn Harbor)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Ag; Au; Pb
Ore minerals galena
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale A-5
Latitude 55.201
Longitude -131.586
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on the shoreline of outer Sylburn Harbor, about 1.8 miles north-northeast of Driest Point. The site is in section 8, T. 77 S., R. 92 E., of the Copper River Meridian. It corresponds to loc. 14 in Berg (1972 [I 684]), loc. 133 in Elliott and others (1978), and loc. 14a-c in Karl (1992). The location is accurate within 0.1 mile.

Geologic setting

Geologic description

The country rock at this site is locally sheared and sericitized Silurian trondhjemite that was regionally metamorphosed to greenschist grade in Late Cretaceous time (Berg, 1972). The occurrence consists of galena in a thin, discontinuous, calcite-quartz fissure vein in a subhorizontal shear zone up to 20 feet thick and several hundred feet long. A grab sample of the sulfide-bearing vein assayed 1.38 oz. Au/ton and 0.42 oz. Ag/ton.
Geologic map unit (-131.587680881529, 55.2006549411775)
Mineral deposit model Polymetallic veins? (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization The fissure vein probably is Late Cretaceous or younger in age.
Alteration of deposit Local sericitization of trondhjemite.

Production and reserves

Workings or exploration A grab sample of the sulfide-bearing vein assayed 1.38 oz. Au/ton and 0.42 oz. Ag/ton (Berg, 1972).
Indication of production None

References