Timberline

Prospects, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu
Ore minerals arsenopyrite; chalcopyrite; gold; pyrite; pyrrhotite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale A-1
Latitude 63.188
Longitude -147.401
Nearby scientific data Find additional scientific data near this location
Location and accuracy The site represents several prospects at an elevation of about 3,950 feet on the west slope of the ridge between Timberline Creek and Valdez Creek. The map site is in the N1/2 of sec. 17, T. 20 S., R. 2 E., of the Fairbanks Meridian. The location is accurate to within 1,000 feet. These prospects are shown as Sites 6 through 10 on Plate I of Smith, 1981.

Geologic setting

Geologic description

The country rock in the area of this site is spotted phyllite, cut by CHLORITIZED DIORITE of probable Cretaceous age. The deposit consists of five veins in shear zones in altered diorite. The largest vein, the Big Caribou, has been traced for 1,000 feet; it is up to 8 feet wide, and contains kidneys and lenses of quartz, arsenopyrite, pyrite, pyrrhotite, and chalcopyrite. Other veins include the Big Water Hole, Freda G., Valdez Creek 6, and Little Caribou. Veins comprise quartz bands up to 2 feet wide. Some of the sulfides also are disseminated in the diorite. The veins appear to be localized in a conjugate fracture system associated with east-trending fault zones. Samples of the veins contain up to 0.33 ounce of gold per ton (Smith, 1981).
Geologic map unit (-147.403259510866, 63.1875514973935)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986, model 22c)
Mineral deposit model number 22c
Age of mineralization Probably Cretaceous or younger.
Alteration of deposit The quartz veins are associated with chloritization of the adjacent diorite.

Production and reserves

Workings or exploration Surface exploration consists of trenches and pits along the traces of the veins. A short adit was driven which encountered the down-dip extension of the Big Caribou and Little Caribou vein systems. Samples of the veins contain up to 0.33 ounce of gold per ton (Smith, 1981).
Indication of production Yes; small
Production notes A small mill was installed in about 1934; it consisted of a jaw crusher, ball mill, classifier, and amalgamating plates. Production was very small.

Additional comments

This was one of the very few lode gold producers in the Valdez Creek drainage.

References