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Collaborative Research: Constraints on the Lithospheric Structure and Accretionary History of New England: Integrating Seismic and Geologic data sets

合作研究：新英格兰岩石圈结构和增生历史的约束：整合地震和地质数据集

基本信息

批准号：
1736167
负责人：
Haiying Gao
金额：
$ 27.49万
依托单位：
University of Massachusetts Amherst
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2021-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736167&HistoricalAwards=false
关键词：
Collaborative Research Constraints Lithospheric Structure

项目摘要

The Wilson tectonic cycle is one of the most fundamental processes leading to growth and modification of continental crust on Earth. It involves the closing of ocean basins, collision of continents, rifting (separation) of continents, and formation of new ocean basins. Eastern North America provides a complete record of the eastward growth of the continent during the closing of the ancestral Atlantic ocean, "Iapetus", and the opening of the modern Atlantic ocean. The region has been used as a type section and model of plate tectonics for decades. Although the surface boundaries between former continental fragments are increasingly well known, a persistent question involves the timing and processes involved with the growth and stabilization of the deep crust and mantle parts of the continent. The overall goal of this project, and a long-term theme of the EarthScope project in general, is to integrate high-resolution geophysical and geological data in order to build a truly four-dimensional (space and time) model for the growth of continental crust in this classic region. The density and distribution of seismic stations are excellent, including the EarthScope Transportable Array and many long-running permanent seismic stations. New geological, geochemical, and geochronological data have led to revision of the tectonic history and a re-assessment of terrane boundaries and ancestry in the northern Appalachians. This proposal aims to understand the characteristics of continental lithosphere (the crust and mantle parts of the tectonic plates) in New York and New England, to identify the boundaries between distinct terranes both at the surface and especially at depth, and to address long-standing open questions about the tectonic history of the northern Appalachians. New models and hypotheses developed in this project will have wide implications for character of the North American continent, the nature of the deep crust and mantle, and our understanding of continental growth in general.This project seeks to associate the interior structure of the lithosphere of Eastern North America with its tectonic history, and to draw broad inferences for the nature of continental assembly. Specifically, this proposal will address the following scientific questions: (1) What is continental lithosphere? Can we identify distinct lithospheric blocks and intra-lithospheric boundaries? What are the origins of these structures? (2) What/where are the major terrane boundaries? To what extent can geological boundaries be extended to depth? When were the major terranes added to the North American continent? To address these questions, the project will develop a comprehensive seismic model of the crust and the mantle lithosphere in eastern North America. An advanced wave propagation simulation and inversion will provide a powerful way to constrain the three-dimensional seismic features of the crust and the mantle lithosphere. Teleseismic receiver function analysis will be used to identify and delineate sharp velocity/density discontinuities. Laterally variable and depth-dependent anisotropy will be resolved with receiver functions and shear-wave splitting studies, and used to highlight patterns of lithospheric deformation. Compilation and synthesis of existing geological data sets, and collection of new surface rock samples will complement the seismic component. A systematic integration of geological, geochronological and geochemical data sets will inform a re-assessment of the regional tectonic framework. The project will support the career development of an early-career female geoscientist and help the development of a new seismology group at UMass Amherst. Expansion of seismology research and teaching has outstanding potential to attract undergraduate and graduate students at the Five-College Geology Consortium. It will support training of undergraduate and graduate students at UMass and Rutgers. Findings from this project will be introduced to 8th-12th grade girls through the Girls Inc. Eureka! Program (a national organization), a strong STEM-based collaboration between Girls Inc. of Holyoke, MA and UMass. Surficial geologic compilations will be uploaded and made available to schools, colleges, and universities throughout New England for critiques, collaboration, and educational use.

威尔逊构造旋回是导致地球大陆地壳生长和变化的最基本的过程之一。它涉及海洋盆地的闭合、大陆的碰撞、大陆的裂谷（分离）和新海洋盆地的形成。北美东部提供了一个完整的记录，记录了在古老的大西洋“Iapetus”关闭和现代大西洋开放期间大陆的向东增长。几十年来，该地区一直被用作板块构造的典型剖面和模式。虽然前大陆碎片之间的表面边界已日益为人所知，但一个持久的问题涉及大陆深部地壳和地幔部分的生长和稳定所涉及的时间和过程。该项目的总体目标，以及EarthScope项目的长期主题，是整合高分辨率地球物理和地质数据，以便在这个经典区域建立一个真正的四维（空间和时间）大陆地壳生长模型。地震台站的密度和分布都很好，包括地球范围可移动阵列和许多长期运行的永久地震台站。新的地质、地球化学和地质年代学数据导致了对阿巴拉契亚北部构造历史的修正和对地界和起源的重新评估。该提案旨在了解纽约和新英格兰大陆岩石圈（构造板块的地壳和地幔部分）的特征，确定地表和深层不同地形之间的边界，并解决有关阿巴拉契亚北部构造历史的长期悬而未决的问题。在这个项目中发展的新模型和假设将对北美大陆的特征、地壳和地幔的深层性质以及我们对大陆生长的一般理解产生广泛的影响。该项目旨在将北美东部岩石圈的内部结构与其构造历史联系起来，并对大陆组合的性质进行广泛的推断。具体来说，本提案将解决以下科学问题：(1)什么是大陆岩石圈？我们能否识别出岩石圈块体和岩石圈内边界？这些结构的起源是什么？(2)主要的地界在哪里？地质边界在多大程度上可以向深处延伸？北美大陆的主要地形是什么时候形成的？为了解决这些问题，该项目将开发一个北美东部地壳和地幔岩石圈的综合地震模型。一种先进的波传播模拟和反演方法将为约束地壳和地幔岩石圈的三维地震特征提供有力的方法。远震接收函数分析将用于识别和描绘急剧的速度/密度不连续。横向可变和深度相关的各向异性将通过接收函数和剪切波分裂研究来解决，并用于突出岩石圈变形模式。现有地质数据集的汇编和综合以及新的地面岩石样本的收集将补充地震成分。对地质、年代学和地球化学数据集的系统整合将为重新评估区域构造格局提供信息。该项目将支持一位早期职业女性地球科学家的职业发展，并帮助在马萨诸塞大学阿默斯特分校建立一个新的地震学小组。扩大地震学的研究和教学对五学院地质联合会吸引本科生和研究生具有突出的潜力。它将支持麻省理工学院和罗格斯大学的本科生和研究生的培训。这个项目的研究结果将通过女孩公司介绍给8 -12年级的女孩。尤里卡!项目（一个全国性组织），是马萨诸塞州霍利奥克女孩公司和马萨诸塞大学之间基于stem的强大合作。地表地质汇编将被上传并提供给整个新英格兰的学校、学院和大学，以供批评、合作和教育使用。