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Potassium-argon ages of basement rocks from Saint George Island, Alaska

July 1, 1978

Potassium-argon ages from basement granitic rocks that intrude serpentinized peridotite on St. George Island, Alaska, range from 50 to 57 million years, with an initial argon isochron age. interpreted as a minimum figure, of 52 ± 2 m.y. The age of the granitic rocks and their association with serpentinized peridotite near the continental margin, which apparently marks the site of a Mesozoic subduction zone, suggest that the position of the subduction zone shifted southward to the Aleutian Trench in early Tertiary time.

Citation Information

Publication Year 1978
Title Potassium-argon ages of basement rocks from Saint George Island, Alaska
Authors D. M. Hopkins, M. L. Silberman
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Research of the U.S. Geological Survey
Index ID 70232571
Record Source USGS Publications Warehouse