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Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in Southwestern Alaska and the Alaska Peninsula

Professional Paper 1497-B

Prepared in cooperation with the Alaska Department of Natural Resources, Division of Geological and Geophysical Surveys
By:
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Abstract

The oldest dated metamorphic sequence in Alaska, the fault-bounded Kilbuck Terrane, consists of continental rocks that were metamorphosed under amphibolite-facies conditions during early Proterozoic (1.77 Ga) time. Proterozoic or early Paleozoic metamorphic ages are also possible for greenschist- and amphibolite-facies continental rocks in interior Alaska (Ruby and Nixon Fork terranes). Medium-grade metamorphism on the Alaska Peninsula accompanied intrusion of a Jurassic arc. North of Bristol Bay, low-grade, locally high-pressure Mesozoic metamorphism is attributed to the progressive underthrusting of a subduction complex beneath an oceanic arc followed by underthrusting of the Kilbuck Terrane beneath the subduction complex.

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Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in Southwestern Alaska and the Alaska Peninsula
Series title:
Professional Paper
Series number:
1497
Chapter:
B
Year Published:
1996
Language:
English
Publisher:
U.S. Government Printing Office
Description:
Report: iii, p. B1-B30; 2 Plates: 40 x 54 inches and 40 x 53.5 inches
Larger Work Title:
Regionally metamorphosed rocks of Alaska
Country:
United States
State:
Alaska