Role of Proterozoic and Paleozoic Volcanic Rocks in the Geologic Evolution of the Southeastern New England Avalon Zone

在阿巴拉契亚造山带内，新英格兰东南部在阿巴拉契亚造山模型中起着关键作用，因为它包含了最后一个增生的地体，似乎拥有最完整的阿勒哈尼亚造山记录。这段历史的一部分涉及火成岩活动，包括晚元古代的弧增生，随后是贯穿古生代大部分时间的幕式伸展的富含石英的碱性岩浆活动，最后是二叠纪短暂的过铝花岗岩侵位。本研究对阿瓦隆地体的两套火山岩进行了广泛的锆石年代学研究。对这些岩石的研究可以阐明新英格兰阿勒卡尼亚造山期碰撞前和早期增生阶段发生的地壳、构造和岩浆过程。

Within the Appalachian orogenic belt, southeastern New England plays a key role in models for Appalachian orogenesis, because it contains one of the last accreted terranes and appears to have the most complete record of the Alleghanian Orogeny. Part of this history involves igneous activity, including late Proterozoic arc accretion, followed by episodic extensional quartz-rich alkalic magmatism throughout much of the Paleozoic succeeded finally by a brief period of peraluminous granite emplacement in the Permian. This study involves extensive zircon geochronology on two suites of volcanic rocks from the Avalon terrane. The study of these rocks may clarify crustal, tectonic and magmatic processes that occurred during the pre-collisional and early accretion stages of the Alleghanian orogenic episode of New England.