Investigating formation and modification of the continental lithosphere in eastern North America - integrating seismic and geologic data sets

研究北美东部大陆岩石圈的形成和改造 - 整合地震和地质数据集

基本信息

批准号：
1930014
负责人：
Haiying Gao
金额：
$ 50.36万
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：
2020
资助国家：
美国
起止时间：
2020-07-15 至 2025-06-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1930014&HistoricalAwards=false
关键词：
Investigating formation modification continental lithosphere

项目摘要

The Wilson cycle paradigm is central to many models for the growth and modification of continental lithosphere (the crust and mantle parts of the tectonic plates) on Earth. The cycle involves the closing of ocean basins, collision of continents, rifting of continents, and formation of new ocean basins. Eastern North America provides a complete record of the eastward growth of the continent from the breakup of supercontinent Rodinia through the assembly of supercontinent Pangea to the formation of the modern Atlantic Ocean. The region provides a superb opportunity to advance our understanding of continental growth and evolution through geologic time, and 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 deeper parts of the continental lithosphere. The overall goal of this project 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 and mantle lithosphere in this classic region. The density and distribution of seismic stations are excellent, including the EarthScope Transportable Array, the Eastern North American Margin Community Seismic Experiment, and many long-running permanent seismic stations. This proposal aims to investigate the characteristics of continental lithosphere in eastern North America, to identify boundaries of distinct tectonic units (microplates), and to address long-standing open questions about the tectonic history of this region. 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 and evolution in general. 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. More broadly, the outcome of this project will be integrated into a two-week Summer Seismology Education Workshop, targeting for the five-college undergraduate students. 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 the east coast for critiques, collaboration, and educational use.This project seeks to associate the interior structure of the eastern North American lithosphere with its tectonic history, and to draw broad inferences for the nature of continental assembly and modification. 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 the boundary structures? (2) What/where are the major crustal terrane boundaries and can these be interpreted in terms of collision (thickening) and extension/exhumation of the orogen? 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 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 continental 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 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 tectonic framework.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

威尔逊周期范式对于许多模型的核心是地球上大陆岩石圈（构造板块的地壳和地幔部分）的生长和修饰的核心。该循环涉及海盆的关闭，大陆碰撞，大陆的裂痕以及新海盆的形成。北美东部提供了从超大型罗迪尼亚（Rodinia）到超大型Pangea的组装到现代大西洋的形成，从而提供了整个大陆向东增长的完整记录。该地区提供了一个极好的机会，可以通过地质时代提高我们对大陆生长和进化的理解，并已被用作板块构造的类型部分和模型数十年。尽管以前大陆碎片之间的表面边界越来越众所周知，但持续的问题涉及与大陆岩石圈更深部分的生长和稳定有关的时间和过程。该项目的总体目标是整合高分辨率的地球物理和地质数据，以建立一个真正的四维（时空）模型，用于在这个经典地区的大陆地壳和地幔岩石圈的生长。地震站的密度和分布非常出色，包括可运输的Earthscope运输阵列，东部北美边缘社区地震实验以及许多长期运行的永久性地震台。该提案旨在调查北美东部大陆岩石圈的特征，以确定不同的构造单位（微板板）的边界，并解决有关该地区构造历史的长期开放问题。该项目中发展的新模型和假设将对北美大陆的特征，深层地壳和地幔的性质以及我们对大陆生长和总体演变的理解具有广泛的影响。该项目将支持早期女性地球科学家的职业发展，并帮助UMass Amherst的新地震学小组的发展。地震研究和教学的扩展具有吸引五大地质财团的本科和研究生的杰出潜力。它将支持UMass的本科和研究生的培训。更广泛地说，该项目的结果将纳入为期两周的夏季地震学教育研讨会，以针对五大学的本科生。该项目的发现将通过女子公司尤里卡（Eureka）介绍给8至12年级的女孩！计划（一个国家组织），这是霍利奥克，马萨诸塞州和马萨诸塞州女孩公司之间的强大合作。将向东海岸的学校，大学和大学上传表面的地质汇编，以进行批判，合作和教育用途。该项目旨在将东北美国岩石圈东部的室内结构与其构造历史联系起来，并诱使大陆汇集和修改的性质。具体来说，该提案将解决以下科学问题：（1）什么是大陆岩石圈？我们可以鉴定出不同的岩石圈块和斜圈内边界吗？边界结构的起源是什么？（2）主要的地壳地层边界在哪里/在哪里，可以用碰撞（增厚）和造山机的延伸/挖掘来解释这些边界？地质边界在多大程度上可以扩展到深度？北美大陆的主要地层何时增加？为了解决这些问题，该项目将开发出北美东部地壳和地幔岩石圈的全面地震模型。高级波传播模拟和反演将提供一种强大的方法来限制大陆岩石圈的三维地震特征。远距离接收器功能分析将用于识别和描述尖锐的速度/密度不连续性。侧面可变和深度依赖性各向异性将通过接收器函数解决，并用于突出岩石圈变形的模式。现有地质数据集的汇编和合成以及新的表面岩石样品的收集将补充地震成分。地质，地质学和地球化学数据集的系统整合将为构造框架的重新评估提供信息。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点和更广泛影响的审查标准通过评估来通过评估来支持的。