1. Mineral Resources
  2. Online Spatial Data
  3. Alaska Resource Data File (ARDF)

Unnamed

Occurrence, Inactive

Map
KML
XML
GeoJSON

Commodities and mineralogy

Main commodities Th; U
Other commodities Ce; Rb

Geographic location

Quadrangle map, 1:250,000-scale MD
Quadrangle map, 1:63,360-scale D-1
Latitude 63.948
Longitude -153.222
Nearby scientific data Find additional scientific data near this location
Location and accuracy Occurrence is situated on a north-south oriented ridge 2 miles (3.2 km) south of Sischu Creek at an elevation of 1,350 feet (411 m) in Section 9, T. 18 S., R. 29 E., of the Kateel River Meridian. Location is accurate to within 500 feet (152 m).

Geologic setting

Geologic description

Miller and others (1980) report anomalous uranium and thorium levels in slightly porphyritic, fine-grained rhyolite. No ore minerals were identified. Two areas of strongly radioactive rhyolite, each about 4 miles long by 1 to 2 miles wide (6.4 km by 0.8 km) , are separated by 2 miles (3.2 km) of ridgeline. Age is inferred to be early Tertiary, based on isotopic ages of Sischu Volcanics (Moll and others, 1981).
Miller and others (1980) report values of 16.4 ppm uranium and 73.8 ppm thorium from grab samples. Clautice and others (1993) report lower uranium and thorium values than those reported by Moll and others (1981), but up to 900 ppm rubidium, and elevated cerium levels.
Geologic map unit (-153.224367196813, 63.9474336402607)
Mineral deposit model Volcanogenic uranium (Cox and Singer, 1986; model 25f).
Mineral deposit model number 25f
Age of mineralization Inferred to be early Tertiary, based on isotopic ages of Sischu Volcanics (Moll and others, 1981).

Production and reserves

Workings or exploration Miller and others (1980) report values of 16.4 ppm uranium and 73.8 ppm thorium from grab samples. Clautice and others (1993) report lower uranium and thorium values than those reported by Miller and others, (1980), but up to 900 ppm rubidium, and elevated cerium levels.
Indication of production None
Reserve estimates None.

Additional comments

See MD001-004.

References

MRDS Number A012441

References

Clautice, K.H., Bowman, N.D., Clough, J.G., Gilbert, W.G., Kline, J.T., Smith, T.E., and Blodgett, R.B., 1993, Land selection unit 8 (Kantishna River, Ruby, and Medfra quadrangles): References, lead isotope, geochemical and major oxide data: Alaska Division of Geological & Geophysical Surveys Public Data File 93-8, 46 p., 1 sheet, scale 1:250,000.
Miller, T.P., Moll, E.J., and Patton, W.W. Jr., 1980, Uranium and thorium rich volcanic rocks of the Sischu Creek area, Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-803, 9 p.
Moll, E.J., Silberman, M.L., and Patton, W.W. Jr., 1981, Chemistry, mineralogy, and K-Ar ages of igneous and metamorphic rocks of the Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811-C, 15 p., 2 sheets, scale 1:250,000.
Reporters Bundtzen, T.K. (Pacific Rim Geological Consulting)
Last report date 6/7/1998