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

现代板块构造理论与新英格兰东部大部分地区由造山过程中吸积到北美的异地地体组成的观点是一致的，但目前的数据不允许区分关于哪个造山事件伴随哪个增生事件的几个假说。该项目将试图确定康涅狄格州东部横断面上地体边界处变质作用的时间和断层活动的时间。角闪石、白云母、黑云母和长石的Ar-Ar年龄谱将在Avalon、Putman-Nashoba和Merrimac地体以及具有重要构造意义的Char湖、Tatnik和Clinton-Newbury边界收集的岩石中进行测量。这些数据将被用来确定地体的毗邻位置是发生在变质前还是变质后，以及断层上的位移程度，从而为古生代活动期间的构造事件的时间提供相当大的约束。

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.