Reconciling extrusion tectonics, rifting, and lithosphere-asthenosphere coupling models for the Central Highlands diffuse igneous province, Vietnam

板块构造的范式代表了地球上最基本的行星过程，是理解地球科学的核心，但关于构造板块的运动和应力如何在许多地区被调节的关键问题仍然存在。构造板块和地幔层之间的关系仍然存在争议，而这些关系对于充分理解是什么驱动地球板块运动是必要的。像印度支那这样的地方特别复杂，受到许多相互竞争的构造和地幔驱动力的影响，因此是更好地了解我们的星球如何作为一个动态的构造系统运行的重要实验室。本研究探讨了越南中部高地近代火山活动和断裂的起源。这项研究的目的是为了更好地了解印度支那的地质环境，特别是构造和地幔过程是如何驱动断层和火山活动的。这项工作对社会有益，因为它通过研究有关地球及其形成过程的基本科学问题，直接促进了科学进步。该研究通过为两位早期职业女性科学家提供支持，有助于扩大代表性不足的群体在科学、技术、工程和数学（STEM）领域的参与。该项目支持STEM教育和研究生和本科生的培训，从而为培养多样化、具有全球竞争力的劳动力做出贡献。该项目将有助于提高公众素养和公众参与STEM支持外展活动与内布拉斯加大学州立博物馆传播科学研究和教育当地社区，并通过一份书面报告，详细介绍有关近期火山喷发时间和新发现断层的潜在危害的任何新发现。该项目促进了美国几所大学之间的合作，以及美国和越南科学家之间的国际合作。具体而言，该项目旨在测试、开发和完善一个强大的、全面的区域模型，以解释印度支那断裂和火山活动的动态起源，从而通过构造地质学和火成岩地球化学的结合方法，增加对复杂制度下构造和地幔动力学的理解。该项目的基本原理是促进对板块边界和微板块动力学以及岩石圈-软流圈耦合效应的科学认识。本研究的中心假设认为，构造挤压和软流圈流动和上升流的耦合作用驱动了南印度支那微板块的旋转，包括走滑和正断层的传播，并产生了大量没有地幔柱参与的地壳岩浆活动。拟建研究的具体研究目标为：1)评估越南中部高原断层运动与火山活动之间的年龄关系；2)收集数据以确定中部高原的应力场，并评估其是否符合挤压或伸展主导的构造制度；3)通过确定随时间和地理分布而喷发的熔岩的地幔源起源（岩石圈与软流圈）来评估同一地区地幔上涌的证据。这些目标将通过断层方向和运动学的现场映射来实现；火山喷发的同位素定年；对比玄武岩和地幔捕虏体中主元素、微量元素和放射性成因同位素的测量结果。该研究预计将引发对火山作用与断裂之间关系的全面评估，构造应力驱动断裂的起源，以及随着时间的推移对当地岩浆来源的识别，从而导致印度支那构造模型的协调。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The paradigm of plate tectonics represents the most fundamental planetary process on Earth and is central to understanding geoscience, but key questions remain about how motion of and stresses in tectonic plates are accommodated in many regions. Relationships between tectonic plates and the underlying mantle layer also remain debated, and those relationships are necessary to fully understand what actually drives plate motion on Earth. Locations like Indochina are particularly complex, influenced by a number of competing tectonic and mantle driving forces, and are thus important laboratories for better understanding how our planet functions as a dynamic, tectonic system. This study investigates the origins of recent volcanic activity and faulting in the Central Highlands of Vietnam. The goal of this research is to better understand the geologic setting of Indochina, particularly what tectonic and mantle processes drive faulting and volcanic activity. This work benefits society because it directly promotes scientific progress by investigating fundamental scientific questions about the planet and processes that shape it. The study contributes to broadening participation of underrepresented groups in science, technology, engineering and mathematics (STEM) by providing support for two early career women scientists. The project supports STEM education and training of graduate and undergraduate students, thus contributing to the development of a diverse, globally competitive workforce. The project will contribute to increased public literacy and public engagement with STEM supporting outreach events with the University of Nebraska State Museum to disseminate scientific research and educate the local community, and through a written report detailing any new findings regarding potential hazards associated with recent volcanic eruption timing and newly discovered faults. The project facilitates collaboration between several U.S. universities, as well as international collaboration between U.S. and Vietnamese scientists. In detail, this project aims to test, develop, and refine a robust, comprehensive regional model that explains the dynamic origins of faulting and volcanism in Indochina, thereby increasing understanding of tectonics and mantle dynamics in complex regimes through the combined approaches of structural geology and igneous geochemistry. The project rationale is the advancement of scientific understanding of plate boundary and microplate dynamics and lithosphere-asthenosphere coupling effects. The central hypothesis for this project states that tectonic extrusion and coupled asthenospheric flow and upwelling have driven rotation of the Southern Indochina microplate, including propagation of strike-slip and normal faulting, and produced voluminous crustal magmatism without mantle plume involvement. The specific research goals for the proposed study are: 1) to evaluate age relationships between fault movement and volcanic activity in the Central Highlands of Vietnam, 2) to gather data to define the stress field of the Central Highlands and assess whether it is consistent with an extrusion- or extension-dominated tectonic regime, and 3) to assess the evidence for mantle upwelling in the same region by identifying mantle source origins (lithosphere vs. asthenosphere) for lavas erupted over time and with geographic distribution. These objectives will be achieved through field mapping of fault orientations and kinematics; isotope dating of volcanic eruptions; and comparative major element, trace element, and radiogenic isotope measurements in basalts and mantle xenoliths. The research is expected to trigger a thorough assessment of relationships between volcanism and faulting, the origin of the tectonic stress driving faulting, and identification of local magma sources over time, leading to a reconciled tectonic model for Indochina.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.