Thermochronology Applied to the Metamorphic and Tectonic History of the Merrimack, Nashoba, and Hope Valley Zones, Southeastern New England

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Modern plate tectonic theory is compatible with the idea that much of eastern New England consists of allochthonous terranes that were accreted to North America during orogenesis, however, present data do not allow discrimination between several hypotheses concerning which orogenic event accompanied which accretion event. This project will attempt to bracket the timing of metamorphism and the timing of fault activity at terrane boundaries across a transect in eastern Connecticut. Argon-argon age spectra from hornblende, muscovite, biotite and feldspar will be measured in rocks collected from the Avalon, Putman-Nashoba and Merrimac terranes and from the tectonically important Lake Char, Tatnik and Clinton-Newbury boundaries. These data will be used to determine if terrane juxta position occurred pre-or post-metamorphism and the degree of displacement on faults and thereby provide considerable constraints on the timing of tectonic events during Paleozoic activity.