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.

板块构造的一个基本思想是，大多数“动作”（地震，火山，断层）发生在板界，而构造板的内部是稳定且不形成的。尽管这对于连续的内部（例如北美）的内部大多是正确的，但地质证据表明，在适当的情况下，以前稳定的连续构造板可以变形，动员和可能的裂谷分开 - 与参与板间隔地震和火山活动。该项目将研究可能导致这种不稳定的关键过程：浮力，热，熔融岩石（岩浆）渗入连续构造板的底部。该项目将探索岩浆在浸润时如何与连续地幔岩石相互作用，以及这种融化岩石相互作用如何深刻改变构造板。该奖项将为一位面临研究障碍的女性中级科学家提供研究和职业增强，使她能够重返尖端研究。此外，该项目将在批判性思维，数据分析，数值建模和机器学习中培训两名女性研究生（其中一名有记录的残疾），为他们做好准备为多样性，全球竞争性的STEM劳动力做出贡献。总体而言，该项目将增强妇女，残疾人和代表性不足的STEM的参与。该项目将结合数据分析，数值建模和机器学习，以对岩浆浸润过程中热和化学二动物在岩浆浸润过程中的后果的影响发展为大陆地幔岩石圈。该团队将探索北美西南部新生代火山岩地球化学的最新见解，以确定岩浆浸润如何在岩石层的物理和化学状态进行逐步转化：从早期（60 MA）俯冲的变形和岩浆到当前（20 MA）状态（MA）状态元素和岩石仪式和岩石仪式和岩石仪式和岩石仪，并相关的岩浆和岩浆。这项研究将测试以下观点：北美西南部物理和化学状态的新生代过渡反映在火山岩中的区域一致的复合过渡中，特别是TA/TH值。将这种过渡作为起点，将开发一种统计方法，以发现火山岩组成中的其他模式，以识别不同样式的岩浆岩石层相互作用。与监督的学习类似，该团队将“训练”其在北美的典型火山岩化学和同位素模式上的统计方法，然后将这些方法应用于藏族高原，这是藏族高原，这是绝对可生存的连续火山主义和岩石圈的绝对持续连续火山和底层降解的另一个区域。地球化学解释将为浸润岩浆和周围岩石圈地幔之间的热和化学二裂的数值模型提供信息。这种综合方法将对岩浆岩石圈相互作用及其在修饰和潜在降解先前稳定的连续岩石圈中的作用产生以过程为导向的理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识分子优点和更广泛的审查标准评估来诚实地获得支持。

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