Interpretation of a high-grade Precambrian terrane in northern Idaho

Geological Society of America Bulletin
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Abstract

A terrane of high-grade metamorphic rocks in northern Idaho and northeastern Washington is almost completely surrounded by low-grade rocks of the Precambrian Belt Supergroup. The high-grade terrane includes both Belt and pre-Belt rocks. Four events of folding and metamorphism occurred in the high-grade terrane. The first three events may have been associated with the Late Cretaceous emplacement of quartz monzonite of the Kaniksu batholith; the fourth may have been associated with a slightly later emplacement of granodiorite or with a Tertiary plutonic and volcanic episode. A much older event of plutonism in the high-grade terrane is recorded by zircon, which was dated by the Pb-U method at 1,500 m.y. from pre-Belt meta-igneous augen gneiss. Evidence of regional events intermediate in age between 1,500 and 100 m.y. has been found in the surrounding low-grade rocks but not in the high-grade terrane.

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Publication type Article
Publication Subtype Journal Article
Title Interpretation of a high-grade Precambrian terrane in northern Idaho
Series title Geological Society of America Bulletin
DOI 10.1130/0016-7606(1973)84<1999:IOAHPT>2.0.CO;2
Volume 84
Issue 6
Year Published 1973
Language English
Publisher Geological Society of America
Description 5 p.
First page 1999
Last page 2004
Country United States
State Idaho
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