Wildcat

Mine, Undetermined

Commodities and mineralogy

Main commodities Au
Other commodities Bi; Cu; Sb
Ore minerals chalcopyrite; gold; pyrite; pyrrhotite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale B-6
Latitude 55.356
Longitude -131.669
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Wildcat mine is at an elevation of about 700 feet, about 1.15 miles southeast of the dam at the outlet of Carlanna Lake. The site is in section 24, T. 75 S., R 90 E., of the Copper River Meridian. It corresponds to loc. 63 in Elliott and others (1978). The location is accurate within about 0.2 mile.

Geologic setting

Geologic description

This part of Revillagigedo Island is underlain mainly by marine, pelitic sedimentary rocks and andesitic or basaltic volcanic rocks that are intruded by Cretaceous stocks, sills, and dikes of feldspar-porphyritic granodiorite, and by a stock and probably related plugs of Tertiary gabbro (Berg and others, 1988). The strata were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. They subsequently were contact metamorphosed to hornblende hornfels: locally, near some of the Cretaceous granodiorite contacts, and, more widely, peripheral to the Tertiary gabbro. The premetamorphic age range of the strata is uncertain. Berg and others (1988) note that they closely resemble Upper Jurassic to mid-Cretaceous flysch and volcanic rocks nearby on Gravina Island. The country rocks are cut by a high-angle fault along Tongass Narrows that displays about 4 miles of right-lateral offset.
The Wildcat deposit consists of two sets of quartz fissure veins in a dioritic dike or sill (called syenite by Wright and Wright, 1908, p. 151-152) that cuts black slate-phyllite (Brooks, 1902, p. 61-62, Cobb and Elliott, 1980, p. 112). The older set, which is roughly parallel to the foliation of the slate-phyllite, contains pyrrhotite. The younger set, which crosscuts the metamorphic foliation, includes the principal vein, which contains free gold, pyrite, and minor chalcopyrite. This vein is up to about 16 inches thick, and was traced on the surface for more than 900 feet. The country rock adjacent to the vein contains disseminated sulfide minerals and, possibly, gold values. The prospect was explored in the early 1900s by opencuts and short tunnels and shafts. A 5-ton test shipment made at that time reportedly contained 1.0-1.5 ounce Au/ton; some gold probably was recovered from this shipment.
According to Brooks (1902, p. 61), a nearby [quartz fissure] vein carries pyrite and pyrite, and reportedly, antimony and bismuth.
Geologic map unit (-131.670685774528, 55.3556530732301)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Cretaceous or younger.
Alteration of deposit The wallrock adjacent to the vein is impregnated with sulfides.

Production and reserves

Workings or exploration The prospect was explored in the early 1900s by opencuts and short tunnels and shafts. A 5-ton test shipment made at that time reportedly contained 1.0-1.5 ounce Au/ton; some gold probably was recovered from this shipment.
Indication of production Yes; small
Production notes A 5-ton test shipment made in the early 1900s reportedly contained 1.0-1.5 ounce Au/ton; some gold probably was recovered from this shipment.

Additional comments

Early reports note that the Wildcat deposit is similar to the one at the Hoadley prospect (KC065).

References