Unnamed (near head of McLeod Bay)

Occurrence, Probably inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Cu; Pb; W; Zn
Ore minerals chalcopyrite; galena; gold; pyrite; sphalerite; tetrahedrite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale DE
Quadrangle map, 1:63,360-scale C-3
Latitude 54.6969
Longitude -132.7268
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is a thin quartz vein exposed for several hundred feet along strike, just below the high-tide line in fresh, wave-washed argillite and meta-andesite. It is about 0.3 mile southeast of the southwest corner of the head of Mc McLeod Bay, in the SW1/4 section 4, T. 83 S., R. 85 E.

Geologic setting

Geologic description

Gehrels (1991) has mapped the rocks in the vicinity as pre-Ordovician, deformed and metamorphosed, sandstone and siltstone that persistently trend about N55W and dip NE.
This quartz vein is not specifically described in the literature, although it was probably known before WWI, when there was considerable prospecting and development in the McLeod Bay area. The vein is particularly well exposed and accessible, carries visible free gold, and is probably similar to the quartz veins higher on the hill to the southwest at the Elk prospect (DE047).
The vein varies from about 2 to 10 inches thick, strikes about N45W and dips 56NE, and can be traced for about 400 feet (D.J. Grybeck, unpublished field notes and analyses, 1984). Typically, calcite and 1 to 3 percent pyrite are scattered through the quartz, but one small pocket of quartz less than a foot long contained about 10 percent sulfides including chalcopyrite, galena, tetrahedrite, and sphalerite, and visible free gold. In general, the vein is parallel to the layering of the black argillite, meta-andesite, and metafelsite host rock. In detail, however, the vein locally crosscuts the host rock and thus is epigenetic. Samples of the vein near the sulfide-bearing pocket contained 50-100 parts per million (ppm) silver, 500-7,000 ppm copper, 100-2,000 ppm lead, up to 300 ppm tungsten, 300-1,500 ppm zinc, and 5 to 10 ppm gold.
Geologic map unit (-132.728463334017, 54.6965559555503)
Mineral deposit model Gold-quartz vein with sparse, scattered sulfides (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization Vein locally crosscuts pre-Ordovician host rock.
Alteration of deposit Not prominent but some of the metafelsite host rock near the vein is bleached (oxidized?).

Production and reserves

Indication of production None

References