Geochronologic and Related Studies, Southern and Central New England

新英格兰阿巴拉契亚山脉南部和中部的古生代变质和变形复杂而多变，试图分离和准确测定构造幕的时间一直很困难。最近对几种常见矿物中阳离子扩散速率的测定，使矿物测年方法能够解决这一构造复杂地区长期缓慢冷却和离散的后期构造事件之间的关系。这项研究将获得高级变质片麻岩和角闪岩中共存矿物的Rb-Sr和Sm-Nd同位素数据，以确定高温变质后最后一次重结晶或开始冷却的时间。使用内部和外部比较和质量平衡考虑的详细分析将允许对该技术进行严格的评估，这是相当普遍的，并可能适用于许多其他造山带地体。这一研究结果将有助于划分中古生代和晚古生代的构造活动特征，对阿巴拉契亚山脉北部构造发展的重大高潮事件有更清晰的认识，并为热模式的构造提供更好的信息库。

Paleozoic metamorphism and deformation in the southern and central New England Appalachians was complex and polyphaze, and attempts to separate and accurately date tectonic episodes has been difficult. Recent determinations of diffision rates of cations in several common minerals allow a mineral dating method to resolve between protracted slow cooling and discrete later tectonic events in this structurally complex region. The study will obtain Rb-Sr and Sm-Nd isotopic data on coexisting minerals in high grade metaigneous gneisses and amphibolites in order to determine the time of last recrystallization or initiation of cooling following high temperature metamorphism. Detailed analyses employing internal and external comparisons and mass balance considerations will permit stringent evaluation of the technique, which is quite general and potentially applicable to many other orogenic terranes. The results of this study will allow features of middle Paleozoic and late Paleozoic orgination to be separated, yielding a clearer understanding of major culminating events in the tectonic development of the northern Appalachians and a improved information base for the constructure of thermal models.