Unnamed (north of Tiekel)

Occurrence, Probably inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Zn
Ore minerals arsenopyrite; galena; gold; limonite; pyrite
Gangue minerals carbonate minerals; chlorite; quartz; white mica

Geographic location

Quadrangle map, 1:250,000-scale VA
Quadrangle map, 1:63,360-scale B-4
Latitude 61.3337
Longitude -145.2968
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is on the east side of Tiekel River valley, about six-tenths of a mile northeast of Tiekel. It is an an elevation of about 1,500 feet near the center of section 19, T. 6 S., R. 1 E., of the Copper River Meridian. This occurrence is probably located to within one-half mile. It is locality 60 of Winkler and others (1981 [OFR 80-892-B]).

Geologic setting

Geologic description

Winkler and others (1981 [OFR 80-892-B]) reported that quartz veins in metaflysch of the Valdez Group contain gold, silver and zinc at this prospect. These veins are probably similar to others that are widespread in the southern Valdez quadrangle. Data summarized by Goldfarb and others (1997) show that gold-bearing quartz veins in the Valdez Group commonly contain pyrite, arsenopyrite, carbonate minerals, chlorite, and white mica and formed from water-rich fluids with 5 to 15 mole percent CO2 and significant amounts of CH4, N2, and H2S. The vein-forming fluid salinities were less than 8 percent, vein formation temperatures ranged from 225 to 375 degrees centigrade, and emplacement depths varied from 3 to 10 kilometers. The vein-forming fluids were produced by metamorphic devolatilization reactions. Radiometric dating indicates that the veins formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171) when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Geologic map unit (-145.298874717152, 61.3332036111455)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Radiometric dating indicates that the gold-bearing quartz veins in the Valdez Group formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171) when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Alteration of deposit Country rocks to gold-bearing quartz veins in Valdez Group metaflysch can be variably silicified, carbonitized, and sericitized (Goldfarb and others, 1997).

Production and reserves

Workings or exploration Small-scale surface prospecting has probably occurred at this locality.
Indication of production Undetermined

References

MRDS Number A011523

References

Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190.
Hudson, T.L., 1994, Crustal melting events in Alaska, in Plafker, G., and Berg, H. C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol. G-1, p. 657-670.
Reporters Travis L. Hudson
Last report date 12/14/2001