COLLABORATIVE RESEARCH: Thermal Evolution of the Maryland Pennsylvania Piedmont: Application of U-Pb Geochronology to Collisional Tectonics

合作研究：马里兰州宾夕法尼亚州皮埃蒙特的热演化：U-Pb 地质年代学在碰撞构造中的应用

• 批准号: 9304708
• 负责人: Maria Crawford
• 金额: $ 8.84万
• 依托单位: Bryn Mawr College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9304708&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Thermal; Evolution; Maryland

The thermal evolution of crust margins involved in collisional processes is an important issue in tectonics, as the thermal and physical modification of the crust through thrust stacking and associated magmatism play an important role in the growth of continents. This project will focus on the piedmont of Maryland, Delaware and Pennsylvania where a continental margin arc developed and subsequently collided with the margin with attendant overthickening by thrust stacking and low pressure, high temperature metamorphism. The work will develop the tectonic chronology of the collisional orogen through high precision U-Pb ages of zircons and monazite from rocks that record the overthickening event and associated magmatism. The duration of the entire orogenic cycle from arc stage through thrust stacking to partial melting can be uniquely determined in the study area, and should provide a benchmark assessment of rates of metamorphic-igneous-tectonic processes in a collisional environment.

碰撞过程中涉及的地壳边缘的热演化是构造学中的一个重要问题，因为通过逆冲堆积和相关岩浆作用对地壳的热和物理改变在大陆的生长中发挥着重要作用。 该项目将重点关注马里兰州、特拉华州和宾夕法尼亚州的山麓，这些地区形成了大陆边缘弧，随后与边缘碰撞，并伴随着逆冲堆积和低压高温变质作用导致的过度增厚。 这项工作将通过记录过度增厚事件和相关岩浆作用的岩石中的锆石和独居石的高精度 U-Pb 年龄来开发碰撞造山带的构造年代学。 从弧阶段到逆冲堆积再到部分熔融的整个造山旋回的持续时间可以在研究区唯一确定，并且应该为碰撞环境中变质火成构造过程的速率提供基准评估。