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

Open-File Report 75-217
By:  and 

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Abstract

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.

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title A reconnaissance study of the U and Th contents of plutonic rocks of the southeastern Seward Peninsula, Alaska
Series title Open-File Report
Series number 75-217
DOI 10.3133/ofr75217
Year Published 1975
Language English
Publisher U.S. Geological Survey
Description 24 p.
Country United States
State Alaska
Other Geospatial southeastern Seward Peninsula
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