Unnamed (near Ruby Creek)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Cu
Ore minerals malachite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale TN
Quadrangle map, 1:63,360-scale B-1
Latitude 65.39112
Longitude -150.26234
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site represents a sample of a copper-quartz-gold vein on the ridge northwest of middle Ruby Creek, 4 miles upstream of its confluence with Minook Creek, and 3 miles upstream from the placer workings on Ruby Creek (TN053; Reifenstuhl and others, 1997 [PDF 97-29h]). The site is at an elevation of 2,000 feet, in the northeast quarter of section 32, T. 7 N., R. 13 W., of the Fairbanks Meridian. The location is accurate.

Geologic setting

Geologic description

The ridge between Russian Creek and Ruby Creek is underlain by pelitic schist and subordinate marble and quartzite, in high-angle fault contact with Triassic (Rampart Group) argillite and chert, gabbro, and diverse schists (Chapman and others, 1982; Reifenstuhl and others, 1997 [RI 97-15a]). The area is cut by the northeast-trending Victoria Creek fault zone, a major dextral fault connecting the Tintina and Kaltag faults (Reifenstuhl and others, 1997 [RI 97-15a]).
In 1996, the Alaska Division of Geological and Geophysical Surveys sampled a 3-foot wide, quartz breccia zone in quartzite on Ruth Creek ridge, about 3.5 miles upstream from the Ruby Creek (TN053) placer deposit (Liss and others, 1997). The sample (number 96RN191) contained 42 parts per billion gold, 3,678 parts per million (ppm) copper, 8.7 ppm silver, 100 ppm cobalt, and 2.1 ppm tellurium. The breccia zone strikes N50E and is marked by prominent copper staining. White mica (sericite) from a quartz vein in this breccia zone yielded an Ar/Ar isotopic age of 61.2 +/- 0.3 Ma (Reifenstuhl and others, 1997 [PDF 97-29h]). Such veins may be the source of some of the placer gold in Ruby Creek.
Geologic map unit (-150.264854180641, 65.3906448882385)
Mineral deposit model Low-sulfide Au-quartz veins? (Cox and Singer, 1986; model 36a?).
Mineral deposit model number 36a?
Age of mineralization White mica (sericite) from a quartz vein in this breccia zone yielded an Ar/Ar isotopic age of 61.2 +/- 0.3 Ma (Reifenstuhl and others, 1997 [PDF 97-29h]).

Production and reserves

Workings or exploration In 1996, the Alaska Division of Geological and Geophysical Surveys sampled a 3-foot wide, quartz breccia zone in quartzite on Ruth Creek ridge, about 3.5 miles upstream from the Ruby Creek (TN053) placer deposit (Liss and others, 1997). The sample (number 96RN191) contained 42 parts per billion gold, 3,678 parts per million (ppm) copper, 8.7 ppm silver, 100 ppm cobalt, and 2.1 ppm tellurium.
Indication of production None

References