CAREER: Investigating the Causes and Consequences of Flat-Slab Subduction in Lithosphere Evolution

职业：研究岩石圈演化中平板俯冲的原因和后果

• 批准号: 1554554
• 负责人: Lijun Liu
• 金额: $ 49.74万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1554554&HistoricalAwards=false
• 关键词: CAREER; Investigating; Causes; Consequences; Flat

How plate tectonics have shaped the Earth's surface geology (such as mountain building, basin formation, landscape evolution, volcanic activities and earthquakes) remains a fundamental question in geosciences. Key to this question is the uncertain variation in the style and dynamics of subduction, a process when cold oceanic plates recycle into the Earth's warm interior. In this proposal, the PI plans to study the causes and consequences of flat-slab subduction (i.e., down-going plates travel sub-horizontally beneath the lithosphere before sinking into the mantle) that has found to be greatly affecting the evolution of continents. This problem has been traditionally difficult to understand due to the many complexities and unknowns involved. Fortunately, the recent progress in geophysical data acquisition and high performance computing make it possible to tackle this important geodynamic problem by building sophisticated physical models using various techniques of data assimilation. Using the PI's previous experience on constructing both forward and inverse data-oriented models (similar to how weather prediction works), the investigator will explore the subduction history in South America, North America and East Asia, where multiple flat-slab epochs have occurred, resulting in the unique geology surrounding the Pacific Ocean. Results from this project will help to better understand not only basic earth evolution but also formation of natural hazards and resources. This project also aims at enhancing communication and education of geodynamic research to both researchers and students. By designing an online interactive geodynamics forum, the PI hopes to promote geodynamic research to the broad Earth science community, and to help interested users to learn geodynamic modeling. The PI plans to develop this geodynamics group into a community hub for doing cross-disciplinary and collaborative research. With multiple research-based flipped-classroom activities, the PI alsoaims to build a modern education culture, with a key focus on nurturing high quality geoscientists for the new century. Finally, this proposal will support and train two PhD students and several undergraduates.It is widely accepted that subduction processes, especially flat-slab subduction, strongly influence the geological evolution of continents and mantle dynamics. However, both the causes and consequences of flat-slab subduction remain elusive. This is largely due to the difficulty to realistically simulate the complex behavior of subduction and its interaction with the overriding continents. In this proposal, the PI plan's to improve our understanding on the physical mechanisms and tectonic consequences of flat-slab subduction by combining advanced data-oriented physical models with geological and geophysical constraints. In practice, he will combine well-established subduction modeling tools (both forward and adjoint methods) with data constraints from multiple disciplines. This comprehensive modeling effort will be applied to three different geographic locations (South America, North America, and East Asia) where flat subduction occurred in the past or is still going on now, and where several different physical mechanisms for slab flattening (subduction of various buoyancy features, fast plate motions, and hydrodynamic suction from the thick overriding plate) could be evaluated. The multidisciplinary nature of this work will make the results highly relevant to many other research fields.

板块构造如何塑造地球表面地质（如造山、盆地形成、地貌演化、火山活动和地震）仍然是地球科学的一个基本问题。这个问题的关键是俯冲的类型和动力学的不确定变化，俯冲是寒冷的海洋板块再循环到地球温暖的内部的过程。在这项提案中，PI计划研究平板俯冲（即下降的板块在沉入地幔之前在岩石圈下方进行亚水平运动）的原因和后果，该俯冲被发现极大地影响了大陆的演化。由于涉及许多复杂性和未知因素，这个问题传统上很难理解。幸运的是，地球物理数据采集和高性能计算的最新进展使得通过使用各种数据同化技术构建复杂的物理模型来解决这一重要的地球动力学问题成为可能。利用 PI 之前构建正向和逆向数据模型的经验（类似于天气预报的工作原理），研究人员将探索南美洲、北美和东亚的俯冲历史，这些地区曾发生过多个平板时代，导致太平洋周围独特的地质。该项目的结果不仅有助于更好地了解地球的基本演化，而且有助于更好地了解自然灾害和资源的形成。 该项目还旨在加强对研究人员和学生的地球动力学研究的交流和教育。通过设计一个在线互动地球动力学论坛，PI希望向广大地球科学界推广地球动力学研究，并帮助感兴趣的用户学习地球动力学建模。 PI 计划将这个地球动力学小组发展成为进行跨学科和协作研究的社区中心。 PI还致力于通过开展多项研究型翻转课堂活动，构建现代教育文化，重点培养新世纪高素质地球科学家。最后，该提案将支持和培养两名博士生和几名本科生。 人们普遍认为，俯冲过程，特别是平板俯冲，强烈影响大陆的地质演化和地幔动力学。然而，平板俯冲的原因和后果仍然难以捉摸。这主要是由于难以真实地模拟俯冲的复杂行为及其与压倒大陆的相互作用。在该提案中，PI 计划通过将先进的面向数据的物理模型与地质和地球物理约束相结合，提高我们对平板俯冲的物理机制和构造后果的理解。在实践中，他将把完善的俯冲建模工具（正向方法和伴随方法）与来自多个学科的数据约束相结合。这项综合建模工作将应用于三个不同的地理位置（南美洲、北美和东亚），这些地点过去发生过或现在仍在发生平坦俯冲，并且存在几种不同的板片平坦化物理机制（各种俯冲作用）可以评估浮力特征、快速板运动以及来自厚覆盖板的流体动力吸力。这项工作的多学科性质将使结果与许多其他研究领域高度相关。

项目成果

Topography and Gravity Reveal Denser Cratonic Lithospheric Mantle Than Previously Thought

地形和重力揭示了克拉通岩石圈地幔比之前认为的更致密

• DOI: 10.1029/2021gl096844
• 发表时间: 2021-12-28
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Yaoyi Wang;Lijun Liu;Quan Zhou
• 通讯作者: Quan Zhou

East Asian lithospheric evolution dictated by multistage Mesozoic flat-slab subduction

• DOI: 10.1016/j.earscirev.2021.103621
• 发表时间: 2021-04-03
• 期刊: Earth-Science Reviews
• 影响因子: 12.1
• 作者: Lijun Liu;D. Peng;Liang Liu;Ling Chen;San;Yaoyi Wang;Zebin Cao;Ming Feng
• 通讯作者: Ming Feng

Modification of the Western Gondwana craton by plume–lithosphereinteraction

地幔柱与岩石圈相互作用对冈瓦纳克拉通西部的改造

• DOI: 10.1038/s41561-018-0064-1
• 发表时间: 2018-03
• 期刊: Nature Geoscience
• 影响因子: 18.3
• 作者: Hu, Jiashun;Liu, Lijun;Faccenda, Manuele;Zhou, Quan;Fischer, Karen M.;Marshak, Stephen;Lundstrom, Craig
• 通讯作者: Lundstrom, Craig

High-resolution lithosphere viscosity and dynamics revealed by magnetotelluric imaging

大地电磁成像揭示的高分辨率岩石圈粘度和动力学

• DOI: 10.1126/science.aaf6542
• 发表时间: 2016-09
• 期刊: Science
• 影响因子: 56.9
• 作者: Liu, Lijun;Hasterok, Derrick
• 通讯作者: Hasterok, Derrick

A Newly Discovered Late‐Cretaceous East Asian Flat Slab Explains Its Unique Lithospheric Structure and Tectonics

• DOI: 10.1029/2021jb022103
• 发表时间: 2021-09-28
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: D. Peng;Lijun Liu;Yaoyi Wang
• 通讯作者: Yaoyi Wang