Abstract: A suite of 50 rock specimens, collected by the 1947 Washburn Mount McKinley Expedition, was scanned radiometrically. The maximum radioactivity observed in any one of the specimens was about twice background. Radiometric analyses of the most radioactive samples show that a sample of vein quartz coated with manganese oxide contains 0.009 percent equivalent uranium and that the maximum equivalent uranium content of granitic rock types is .004 percent. The radioactivity of the manganese-stained quartz is probably due to traces of uranium in the manganese mineral, whereas that of the granitic rocks is due to radioactive accessory minerals.

The following report discusses radioactive results found in 4 samples of gneissic granite of 13 samples collected from the Mount Michelson area of northeastern Alaska. A mineralogic study of all heavy-mineral fractions having more than 0.01 percent equivalent uranium indicates that the radioactive material apparently is confined to biotite, which in one sample contains 1.19 percent uranium.

Report discussing a study in which a suite of 50 rock specimens collected by the 1947 Washburn Mount McKinley Expedition was scanned radiometrically.

The following report presents results of radiometric and mineralogic studies made on 13 samples taken from the Mount Michelson area, Alaska.

A report regarding a reconnaissance performed Along the Upper Porcupine River, Northeastern Alaska for radioactive deposits.