Unnamed (Tatonduk River)

Occurrence, Probably inactive

Commodities and mineralogy

Main commodities Fe
Ore minerals hematite

Geographic location

Quadrangle map, 1:250,000-scale CY
Quadrangle map, 1:63,360-scale A-1
Latitude 65.036
Longitude -141.099
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence consists of scattered redbed outcrops for nearly 2 miles along the lower Tatonduk River and extends into the high country on both sides of the river. The outcrop area encompasses most of the northwest quarter of T. 2 N., R. 33 E., of the Fairbanks Meridian, and the southwest quarter of T. 3 N., R. 33 E., of the Fairbanks Meridian. The coordinates are for the approximate center of the outcrop area, in section 6, T. 2 N., R. 33 E., of the Fairbanks Meridian. The occurrence is location 2 of Cobb (1972; MF-0390). The location is accurate.

Geologic setting

Geologic description

This occurrence is a redbed unit of the Precambrian Tindir Group (Kimball, 1969). The Tindir Group is about 2,200 to 2,600 feet thick and in addition to the redbed unit includes argillite, shale, slate, conglomerate, extrusive volcanic rocks, and dolomitic rocks. The beds are in a monoclinal sequence that dips irregularly as much as 30 degrees west and is cut by at least one low-angle thrust fault (Mertie, 1933). Much of the cement in the redbed unit is hematite, and some beds are nearly entirely hematite (Mertie, 1933). The material is not suitable for magnetic or simple gravity separation (Kimball, 1969).
The outcrop area of the redbed unit is more than 6 square miles, and nearly 800 feet of stratigraphic thickness was sampled in 1969 (Kimball, 1969). Sample chips assayed 4.73 to 24.7 percent soluble iron. A 133-foot-thick section assayed 10 to 20 percent soluble iron, and a 200-foot-thick section assayed 21.85 percent soluble iron. These were the highest assays for the thickest sections of material.
Geologic map unit (-141.10134268159, 65.035728464488)
Mineral deposit model Superior Fe (Cox and Singer, 1986; model 34a).
Mineral deposit model number 34a
Age of mineralization Precambrian.

Production and reserves

Workings or exploration The Tatonduk River prospect has been known since at least 1933 and was assayed and sampled in 1969 (Kimball, 1969).
Indication of production None

Additional comments

This site is within the Yukon-Charley Rivers National Preserve.