Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Mo; Pb; Zn
Other commodities Ba
Ore minerals barite; chalcopyrite; galena; pyrite; pyrrhotite; sphalerite

Geographic location

Quadrangle map, 1:250,000-scale TY
Quadrangle map, 1:63,360-scale C-5
Latitude 61.7083
Longitude -151.7876
Nearby scientific data Find additional scientific data near this location
Location and accuracy T-Bird is located about 3.5 miles southeast of Hayes River Pass; about 0.2 mile east of the center of section 27, T. 19 N., R. 14 W., of the Seward Meridian. The location is accurate to within 100 feet of the center of the occurrence (Ellis, 1994).

Geologic setting

Geologic description

T-bird is an occurrence in the Beluga Project Area. This area is made of Cretaceous sedimentary units that have been intruded by 62 Ma felsic hypabyssal rocks and exhibits porphyry style alteration and lead-zinc-silver mineralization. Numerous color anomalies were noted in the lower parts of the stream valleys within the felsic package and massive sulfide float boulders were also discovered (Ellis, 1994). The Cook Inlet region geologic map (Wilson and others, 2012) shows that this occurrence occurs in an area of intermediate composition Cretaceous volcanic and sedimentary rocks overlain by Tertiary or Cretaceous age felsic tuff.
The T-bird occurrence is characterized by a fault-controlled massive sulfide vein consisting of massive pyrite-pyrrhotite + chalcopyrite, galena and sphalerite in a silica-rich matrix. This vein is 1-2 feet thick and can be traced about 50 feet. It trends north, is near vertical and is hosted by rhyolite. High-grade base metal samples carried up to 4 ounces of silver per ton and up to 0.68 percent molybdenum. Drainages below and to the north of T-bird contained from 20 to 73 parts per million (ppm) molybdenum and 50 to 356 ppm copper. Copper and molybdenum anomalies have been identified in stream sediment samples (Ellis, 1994).
Geologic map unit (, )
Mineral deposit model Kuroko massive sulfide (Cox and Singer, 1986; model 28a).
Mineral deposit model number 28a
Age of mineralization Analysis from a fine-grained porphyry returned an age of 62 million years using argon-argon dating analyzed by the University of British Columbia petrology lab (Ellis, 1994).
Alteration of deposit Silicification (Ellis, 1994).

Production and reserves

Workings or exploration
In 1993, a reconnaissance effort was carried out by American Copper and Nickel Company's 'Alaska Task Force' to identify targets for future work (Ellis, 1994).
Exploration by American Copper and Nickel Company in 1994 focused on mapping, sampling and prospecting. Seven rock samples and five stream samples from T-bird were collected and analyzed. Average results were 25 parts per billion (ppb) gold, 134 parts per million (ppm) silver, 1.6 percent copper, 10.3 percent lead, and 0.7 percent molybdenum (Ellis, 1994).
Indication of production None



Reporters V.C. Zinno (Alaska Earth Sciences, Inc.)
Last report date 3/15/2016