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Isotopic evidence for early Proterozoic age of the Idono Complex, west-central Alaska

Journal of Geology

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, , , ,

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Abstract

The Idono Complex is a fault-bounded, ~300 km2 fragment of Early Proterozoic continental crust surrounded by overlap assemblages and younger terranes accreted in Mesozoic time. It is composed of granitic to dioritic orthogneiss, amphibolite, and metasedimentary rocks. Trace element compositions of the granitoids and amphibolite suggest rock formation in a subduction-related volcanic arc terrain. Nine zircon fractions from three samples of granitoid orthogneiss define a U-Pb discordia line intersecting concordia at 2062 ?? 7 Ma and 182 ?? 8 Ma. The upper and lower intercepts are interpreted, respectively, as approximations of the time of granitoid crystallization and major episodic Pb-loss. Rocks of the Idono Complex may provide important insights into both Early Proterozoic evolution along the craton margin, and subsequent displacements. -from Authors

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Isotopic evidence for early Proterozoic age of the Idono Complex, west-central Alaska
Series title:
Journal of Geology
Volume
99
Issue:
2
Year Published:
1991
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Geology
First page:
209
Last page:
223
Number of Pages:
15