RECONNAISSANCE STUDY OF THE URANIUM AND THORIUM CONTENTS OF PLUTONIC ROCKS OF THE SOUTHEASTERN SEWARD PENINSULA, ALASKA.

Reconnaissance studies of these plutons have shown that the Darby pluton has well above average amounts of uranium and thorium (11. 2 ppm and 58. 7 ppm, respectively), the Kachauik pluton contains average to above average uranium and thorium (5. 7 ppm and 22. 5 ppm, respectively), and the Bendeleben pluton contains average amounts of uranium and thorium (3. 4 ppm and 16. 7 ppm, respectively). The three plutons show compositional and textural differences indicative of different source materials that may have controlled the distribution of uranium and thorium. The high uranium and thorium contents of the Darby pluton, similar to those of the Conway Granite of New Hampshire which has been mentioned as a possible low-grade thorium resource, suggest that this pluton may be a favorable area for economic concentrations of uranium and thorium.