Timing of Paleozoic Metamorphism and Magmatism in the Appalachians of Northern Massachusetts and Southern New Hampshire

新英格兰地区晚前寒武纪、奥陶系、志留纪和泥盆纪的变质层状和侵入岩记录了一段极其复杂的“阿卡迪亚”碰撞史。最近对马萨诸塞州中部布朗森山背斜和梅里马克向斜的放射性年龄测定结果揭示了两个不同的“阿卡迪亚”（早泥盆世和晚泥盆世）变质组，它们被一个普遍较高压力的晚宾夕法尼亚变质带隔开。该项目将跟踪该地区的这些特征，以确定它们的空间分布，并获得新英格兰阿巴拉契亚山脉时间演变的更精确图像，并提高对其在造山带更大框架内设置的理解。

The metamorphosed stratified and intrusive rocks of late Precambrian, Ordovician, Silurian and Devonian age in New England records an extremely complicated "Acadian" collisional history. Recent results of radiometric age dating in the Bronson Hill anticlinorium and Merrimack synclinorium of central Massachusetts has revealed two distinct age groups of "Acadian" (early and late Devonian) metamorphism separated by a generally higher pressure zone of late Pennsylvanian metamorphism. This project will follow these features i the region to determine their spatial distribution and to obtain a more precise picture of the temporal evolution of the New England appalachians, and to improve understanding of its setting within the larger framework of the orogen.