CAREER: Exhumation of a High-Grade Metamorphic Terrane, and Late-Stage Orogenic Collapse in the Southeastern New England Appalachians

阿巴拉契亚山脉是一个复合山脉带，由各种微大陆、海洋和大陆火山弧以及在阿巴拉契亚山脉造山事件中碰撞的（Meta）沉积域组成。在阿巴拉契亚山脉的地质调查通常强调各种化石的融合历史。该建议的重点是同碰撞后的更深的域的折返历史，以及后期崩溃的山带，以获得基本的见解后期到后山形成过程中的北方阿巴拉契亚山脉及以后。在阿巴拉契亚山脉东南部的新英格兰地区，通过一个强有力的综合研究和教育计划进行研究。东南部的新英格兰阿巴拉契亚山脉通常由三个山脉组成。从西到东分别是梅里马克、纳什巴和阿瓦隆。Nashoba断层以适度NW倾斜断层为界。初步现场数据表明，根据褶皱几何形状、变质特征以及纳什巴火山岩中约3.95亿年熔融物与结构上覆的梅里马克火山岩中约3.95亿年侵入物之间的明显关系，纳什巴火山岩中较深的区域可能向东挤压。此外，初步的实地观察表明，大多数间和内剪切带显示出后期低级正常运动的证据，推测与后期山体崩塌有关。本研究的目的是通过野外测绘、详细的结构分析和尖端的放射性测年技术相结合，调查高温和低温的折返和塌陷机制。将研究和野外工作融入本科生的经验是本项目的核心。鼓励来自波士顿地区各个地球科学部门的学生通过地质实地研究课程参与和合作，为他们提供与同行讨论研究并创建更强大社区的绝佳机会。本科生和MS学生的后续论文研究涉及波士顿学院，麻省理工学院和UMass Amherst的分析工作，加强了三个实验室之间以及学生和教师之间的关系。学生，特别是妇女和少数民族学生，被鼓励通过现有的课程，部门咨询活动和其他地球科学部门参与。来自代表性不足群体的学生通过波士顿学院AHANA（非洲裔美国人，西班牙裔，亚洲人和美洲原住民）学生办公室和McNair计划为低收入和第一代大学参与者的本科生和/或代表性不足群体的一部分。该项目的资金由美国国家科学基金会地球观测和教育与人力资源计划提供。

The Appalachians are a composite mountain belt consisting of various microcontinents, oceanic and continental volcanic arcs and (meta)sedimentary domains that collided during the Appalachian mountain building events. Geological investigations in the Appalachian commonly emphasize the amalgamation history of the various terranes. This proposal focuses on the syn- to post-collisional exhumation history of the deeper domains, as well as late-stage collapse of the mountain belt, to gain fundamental insights into late- to post-mountain formation processes in the northern Appalachians and beyond. Research is carried out in the southeastern New England section of the Appalachians through a strongly integrated research and educational plan.The southeastern New England Appalachians generally consist of three terranes. From west to east they are the Merrimack, Nashoba and Avalon terranes. The Nashoba terrane is bounded by moderately NW-dipping faults. Preliminary field data suggest that deeper domains within the Nashoba terrane may have extruded towards the east, based on fold geometries, metamorphic characteristics and the apparent relationship between approximately 395 million year melts in the Nashoba terrane and approximately 395 million year intrusions in the structurally overlying Merrimack terrane. Furthermore, preliminary field observations indicate that most inter- and intra-terrane shear zones show evidence for late low-grade normal movement, presumably related to late-stage mountain collapse. The purpose of this research is to investigate both the high-temperature and low-temperature exhumation and collapse mechanisms through a combination of field mapping, detailed structural analysis and cutting-edge radiometric dating techniques.Integration of research and field work into the undergraduate student experience is central to this project. Students from various geoscience departments in the Boston area are encouraged to participate and collaborate through a Geological Field Research course, giving them an excellent opportunity to discuss research with their peers and creating a stronger community. Subsequent thesis research by undergraduate and MS students involves analytical work at Boston College, MIT and UMass Amherst, strengthening the relationship between the three labs and between students and faculty. Students, especially women and minority students, are encouraged to participate through existing courses, departmental advising activities and other geoscience departments. Students from underrepresented groups are reached through the Boston College AHANA (African-American, Hispanic, Asian and Native American) student office and the McNair program for undergraduates who are low-income and first-generation college participants, and/or part of underrepresented groups. Funding for this project is provided by the NSF EAR Tectonics Program, with support from the NSF EAR EarthScope and Education and Human Resources Program.