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Science 14 August 1964:
Vol. 145. no. 3633, pp. 705 - 707
DOI: 10.1126/science.145.3633.705
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Articles

Potassium-Argon and Lead-Alpha Ages of Plutonic Rocks, Bokan Mountain Area, Alaska

Marvin A. Lanphere 1, E. M. MacKevett Jr. 1, and T. W. Stern 2

1 U. S. Geological Survey, Menlo Park, California
2 U. S. Geological Survey, Washington, D.C.

Most of the granitic rocks in the Bokan Mountain area, southeastern Alaska, are early Paleozoic (probably Ordovician) judged by potassium-argon and lead-alpha age measurements. The Bokan Mountain Granite, the youngest intrusive unit in the area, belongs to a Mesozoic plutonic episode. These age measurements are the first direct evidence for the emplacement of early Paleozoic granitic intrusive rocks close to the Pacific margin of North America.

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Science. ISSN 0036-8075 (print), 1095-9203 (online)