Table Mountain

Prospect, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Cu; Zn
Ore minerals arsenopyrite; chalcopyrite; enargite; gold; pyrrhotite; sphalerite
Gangue minerals biotite; quartz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale CI
Quadrangle map, 1:63,360-scale B-4
Latitude 65.447
Longitude -145.915
Nearby scientific data Find additional scientific data near this location
Location and accuracy This location is approximately 3/4 km west of Table Mountain summit. The prospect is on black biotite schist that contains up to 140 ppm gold (Menzie and others, 1987). Table Mountain is located approximately 4 miles NE of Twelve Mile Summit along the Pinnel Mountain trail, in sec. 9, T. 7 N., R. 9 E.

Geologic setting

Geologic description

The metamorphic rocks in the Table Mountain area belong to the quartzite and quartzitic schist unit of Foster and others (1983) and are composed of light gray quartzite, black biotite schist, fine-grained greenish-gray mafic rocks and light-greenish-gray calc-silicate rocks (Burack, 1983). Granite crops out over an area of only about 2 square km, but the distribution of contact metamorphosed rocks suggests that granite underlies much of the Table Mountain area at relatively shallow depths (Burack, 1983).
Menzie and others (1987), reported that the highest concentrations of gold (2.6 to 140 ppm) occur just west of Table Mountain in black biotite schist and in quartz veins adjacent to a fault zone (breccia in granite) that is intruded by a sulfide-bearing hypabyssal felsic dike. Gold was detected in lesser amounts (0.05 to 0.2 ppm) in country rocks adjacent to a granite pluton that crops out five km to the northeast of the black biotite schist. The occurrences contain pyrrhotite, arsenopyrite, minor chalcopyrite, and rare enargite and sphalerite (Menzie and others, 1987, p. 1).
The Table Mountain occurrences show traces of silver and low levels of tin in the hypabyssal dike and in an iron-stained sample of the breccia. Two samples of a quartz vein containing sulfides along the vein walls both contained high values of gold, arsenic, and copper. Antimony was detected in both samples (Menzie and others, 1987, p. 4).
In the occurrences in and adjacent to the granite, gold was detected only in the sulfide-bearing hypabyssal felsic dike. Silver and tin were detected in the dike and in the granite adjacent to the dike. A sample of this dike without sulfides contained detectable tin but not gold or silver. A sample of quartzite from adjacent to the pluton did not contain gold, silver, or tin in detectable amounts (Menzie and others, 1987, p. 4).
In 1986, Alaska Division of Geological and Geophysical Surveys collected samples of auriferous tourmaline-quartz veins and hornfelsed biotite-tourmaline schists from the Table Mountain area. Field work in 1987 showed that the biotite-tourmaline schists and tourmaline-quartz veins are present throughout much of the north side of Table Mountain and that they are not restricted to fault zones. The widespread distribution of these veins is attributed either to (1) remobilization from stratiform occurrences or (2) hydrothermal mineralization associated with nearby abundant felsite dikes. These widspread occurrences suggest that this area has significant lode gold potential (Smith and others, 1987, p. 6-15).
Claims were active in 1981, but type of work is unknown (Menzie and others, 1983).
Geologic map unit (-145.917466741812, 65.4466134859131)

Production and reserves

Workings or exploration Surface rock samples taken. Claims were active in 1981 but type of work is unknown (Menzie and others, 1983).
Indication of production None

References