Unnamed (on Ham Island)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Au
Ore minerals gold
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale A-5
Latitude 55.181
Longitude -131.368
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site consists of three occurrences on the southwest shore of Ham Island, about midway in Cascade Inlet. The 0.2-mile-long strip of shoreline that contains the occurrences is in sections 22 and 23, T. 77 S., R. 93 E., of the Copper River Meridian. The site corresponds to loc. 10 in Berg (1972 [I 684]), loc. 139 in Elliott and others (1978), and loc. 25a-c in Karl (1992). The location is accurate within 0.1 mile.

Geologic setting

Geologic description

The country rocks at this site are Jurassic and Cretaceous flyschlike metasedimentary rocks that grade upward into andesitic or basaltic metavolcanic rocks (Berg, 1972). The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time.
The occurrences consist of traces of gold in quartz fissure veins that cut the metasedimentary rocks, and traces of gold in a small beach placer. A pan concentrate of beach gravel contained 0.05 ppm Au, 500 ppm Cu, and 200 ppm Pb; and samples of pyritic tuff and a quartz-pyrite vein respectively contained 0.7 ppm Ag and 0.05 ppm Au (Karl, 1992, loc. 25a-c).
Geologic map unit (-131.369683646597, 55.1806583264978)
Mineral deposit model Low-sulfide Au-quartz veins; Placer Au-PGE (Cox and Singer, 1986; models 36a, 39a)
Mineral deposit model number 36a, 39a
Age of mineralization Fissure veins are Cretaceous or younger; placer is Holocene.

Production and reserves

Indication of production None

References