MCA: Destroying continental plates - unraveling the role of magmatism

MCA：摧毁大陆板块——揭示岩浆作用的作用

• 批准号: 2120812
• 负责人: Mousumi Roy
• 金额: $ 32.42万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2120812&HistoricalAwards=false
• 关键词: MCA; Destroying; continental; plates; unraveling

A fundamental idea of plate tectonics is that most of the ‘action’ (earthquakes, volcanoes, faulting) happens at plate boundaries and that the interiors of tectonic plates are stable and undeforming. While this is mostly true for the interiors of continents (such as North America), geologic evidence shows that under the right circumstances previously stable continental tectonic plates can deform, mobilize and possibly rift apart—with accompanying plate-interior earthquake and volcanic activity. This project will investigate one of the key processes that may lead to this destabilization: the infiltration of buoyant, hot, molten rock (magma) into the base of a continental tectonic plate. This project will explore how magma interacts with the continental mantle rocks as it infiltrates and how such melt-rock interaction may profoundly alter tectonic plates. This award will provide research and career enhancement to a female mid-career scientist who has faced barriers to research, allowing her to return to cutting-edge research. Additionally, the project will train two female graduate students (one of whom has a documented disability) in critical thinking, data analysis, numerical modeling, and machine learning, preparing them to contribute to a diverse, globally competitive STEM workforce. Overall, the project will enhance the participation of women, persons with disabilities, and underrepresented minorities in STEM. This project will combine data analysis, numerical modeling, and machine learning to develop a process-oriented understanding of the consequences of thermal and chemical disequilibrium during magma-infiltration into the continental mantle lithosphere. The team will exploit recent insights from the geochemistry of Cenozoic volcanic rocks in southwestern North America to determine how magma-infiltration aided in a progressive transformation of the physical and chemical state of the lithosphere: from earlier (60 Ma) subduction-related deformation and magmatism to the current (post 20 Ma) state of extension/transtension and associated magmatism. The research will test the idea that the Cenozoic transition in the physical and chemical state of southwestern North America is reflected in a regionally-consistent compositional transition in volcanic rocks, specifically in Ta/Th values. Using this transition as a starting point, a statistical methodology will be developed for uncovering other patterns in volcanic rock compositions in order to identify different styles of magma-lithosphere interaction. In analogy with supervised learning, the team will “train” its statistical methods on canonical volcanic rock chemical and isotopic patterns in North America, and then will apply these methods to “test” data from the Tibetan Plateau, another region of abundant Cenozoic continental volcanism and lithosphere degradation. The geochemical interpretations will inform numerical models of thermal and chemical disequilibrium between infiltrating magma and the surrounding lithospheric mantle. This integrative approach will yield a process-oriented understanding of magma-lithosphere interaction and its role in modifying and potentially degrading previously stable continental lithosphere.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.

板块构造学的一个基本观点是，大多数“活动”（地震、火山、断层）发生在板块边界，构造板块的内部是稳定和未变形的。 虽然这对于大陆内部（如北美）来说大多是正确的，但地质证据表明，在适当的情况下，以前稳定的大陆构造板块可以变形，移动，并可能分裂-伴随着板块内部的地震和火山活动。该项目将研究可能导致这种不稳定的关键过程之一：浮力、热、熔融岩石（岩浆）渗透到大陆构造板块的底部。 这个项目将探索岩浆如何与大陆地幔岩石相互作用，因为它渗透，以及这种熔体岩石相互作用如何可能深刻地改变构造板块。该奖项将为面临研究障碍的女性职业中期科学家提供研究和职业提升，使她能够重返前沿研究。此外，该项目还将培训两名女研究生（其中一名有记录的残疾）批判性思维，数据分析，数值建模和机器学习，使她们为多元化，具有全球竞争力的STEM劳动力做出贡献。总体而言，该项目将提高妇女、残疾人和代表性不足的少数群体在STEM中的参与。该项目将结合联合收割机数据分析、数值模拟和机器学习，以发展对岩浆渗入大陆地幔岩石圈期间热化学不平衡后果的过程导向理解。该团队将利用最近对北美西南部新生代火山岩地球化学的认识，以确定岩浆渗透如何帮助岩石圈物理和化学状态的逐步转变：从早期（60 Ma）俯冲相关的变形和岩浆活动到当前（20 Ma后）的伸展/平移状态和相关的岩浆活动。该研究将测试的想法，新生代的物理和化学状态的北美西南部的转变反映在一个区域一致的火山岩成分的转变，特别是在Ta/Th值。将以这一转变为起点，发展一种统计方法，以揭示火山岩成分的其他模式，从而查明不同类型的岩浆-岩石圈相互作用。 与监督学习类似，该团队将在北美典型的火山岩化学和同位素模式上“训练”其统计方法，然后将这些方法应用于“测试”青藏高原的数据，青藏高原是另一个丰富的新生代大陆火山活动和岩石圈退化的地区。地球化学解释将为渗透岩浆和周围岩石圈地幔之间的热平衡和化学不平衡的数值模型提供信息。这种综合方法将产生一个过程为导向的理解岩浆岩石圈的相互作用及其作用，在修改和潜在的退化以前稳定的大陆lithosepher.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

项目成果

Assessing the role of thermal disequilibrium in the evolution of the lithosphere–asthenosphere boundary: an idealized model of heat exchange during channelized melt transport

评估热不平衡在岩石圈-软流圈边界演化中的作用：通道化熔体传输过程中热交换的理想化模型

• DOI: 10.5194/se-13-1415-2022
• 发表时间: 2022
• 期刊: Solid Earth
• 影响因子: 3.4
• 作者: Roy, Mousumi