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A reconnaissance study of the U and Th contents of plutonic rocks of the southeastern Seward Peninsula, Alaska

January 1, 1975

Large granitic Cretaceous plutons are exposed along and adjacent to an arcuate belt of igneous and high-grade metamorphic rocks in the southeastern Seward Peninsula of Alaska. Reconnaissance studies of these plutons have shown that the Darby pluton has well above average amounts of U and Th (11.2 ppm and 58.7 ppm respectively), the Kachauik pluton ranges from average to above average U and Th (5.7 ppm and 22.5 ppm respectively), and the Bendeleben pluton contains average amounts of U and Th (3.4 ppm and 16.7 ppm respectively). The three plutons show compositional and textural differences indicative of different source materials which may have controlled the distribution of U and Th.

The high U and Th contents of the Darby pluton, similar to that of the Conway Granite of New Hampshire which has been mentioned as a possible low grade Th resource, suggests that this pluton may be a favorable area for economic concentrations of U and Th.

Publication Year 1975
Title A reconnaissance study of the U and Th contents of plutonic rocks of the southeastern Seward Peninsula, Alaska
DOI 10.3133/ofr75217
Authors Thomas P. Miller, Carl M. Bunker
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 75-217
Index ID ofr75217
Record Source USGS Publications Warehouse