Eclogitization of continental lithosphere from subduction zone devolatilization

俯冲带是一个构造板块在另一个构造板块之下滑动和下沉的区域，由于它们与造山运动和地震和火山爆发等自然灾害有关，它们一直是地球科学领域研究的主要焦点。提高对这些岩石下沉到地球内部的过程的理解，即所谓的下沉，对俯冲带和大陆地壳研究具有宝贵的见解。下沉过程要求岩石的密度大于周围环境。本项目将探讨控制下陆壳岩石因矿物转化而密度增大的过程，以及这一过程在多大程度上需要俯冲带常见的流体介导反应。这项建模研究的结果将与挪威发现的岩石进行比较，这些岩石被认为在经历了这种致密化过程后返回到表面。该研究项目由一位早期职业调查员领导，他将通过带头这项研究和指导博士后学者来获得宝贵的经验。为了确保透明度并鼓励项目以外的合作，项目的所有数据和结果都将公开，其研究结果将在国家和国际会议上向各种受众介绍。该项目将有助于本科研究人员，K-12科学教师和来自不同背景的高中生的培训。这将通过在格鲁吉亚理工学院的本科生暑期研究经验（REU）计划中提供实践研究经验，并与教育中心合作，将科学，数学和计算（CEISMC）引入编码和地球科学概念，以亚特兰大大都会地区的K-12学生。格鲁吉亚实习教师奖学金（GIFT）计划将提供资金，以支持K-12教师和高中学生，使他们能够开发适合年级的教材和科学项目。这些教育资源将在当地的科学博览会上展示，目的是激发年轻人的思想，培养他们对地球科学和编码的早期兴趣。该项目旨在解决一个值得注意的知识差距，即地球表面之下的造山过程（称为造山作用）背后的机制。该项目的主要重点是了解地壳深部反应流体的作用和榴辉岩化的热力学。为了实现这一目标，该项目旨在开发先进的模型，将榴辉岩化的热力学与流体流动的模拟相结合。这些模型将使研究人员能够研究流体和榴辉岩化过程之间的相互作用，并确定与变质作用和岩石圈下沉有关的时间尺度。该项目将包括两个相互关联的数值模拟研究。首先，将开发非平衡热力学模型以捕获关键矿物相和反应的行为。然后，这些模型将与流体流动和岩石变形的模拟相结合。为了验证并从模型中获得见解，研究人员将比较模型输出与挪威记录良好的榴辉岩中观察到的颗粒尺度到区域尺度的结构。这一分析将使他们能够检验岩石圈沉降是一种全球现象和造山作用的结果这一假设。此外，该模型将提供有价值的信息，榴辉岩化的具体条件下，成为有利的地质条件和时间尺度所需的大量积累的榴辉岩在下地壳。研究人员将在各种各样的初始岩石成分中探索这些过程，这些岩石成分代表了地球大陆地壳中发现的各种各样。最终，该项目旨在提高我们对山脉形成过程中发生的复杂变质和交代过程的整体理解。 该项目得到了地球物理学和岩石学及地球化学项目的支持。该奖项反映了NSF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。

Subduction zones are regions where one tectonic plate slides and sinks beneath another, and they have been a major focus of research in the field of Earth Science due to their association with mountain-building and with natural hazards like earthquakes and volcanic eruptions. Improving the understanding of processes involving the sinking of these rocks into the Earth's interior, known as foundering, holds valuable insights for subduction zones and continental crust research. The foundering process requires the rocks are of greater density than their surroundings. This project will explore the processes controlling the transformation of rocks in the lower continental crust to greater density resulting from mineral transformations and the degree to which the process requires fluid-mediated reactions common in subduction zones. The results of this modeling study will be compared to rocks found in Norway that are thought to have returned to the surface after undergoing this densification process. The research project is led by an early career investigator, who will gain valuable experience by spearheading this study and mentoring a postdoctoral scholar. To ensure transparency and encourage collaboration beyond this project, all the project's data and results will be made publicly accessible, and their findings will be presented at conferences both nationally and internationally to a variety of audiences. This project will contribute to the training of undergraduate researchers, K-12 science teachers, and high school students from diverse backgrounds. This will be accomplished through providing hands-on research experience in Georgia Tech’s Summer Research Experiences for Undergraduates (REU) program, and collaboration with the Center for Education integrating Science, Mathematics, and Computing (CEISMC) to introduce coding and Earth Science concepts to K-12 students in the Atlanta Metro area. The Georgia Intern Fellowships for Teachers (GIFT) program will provide funding to support a K-12 teacher and high school students, enabling them to develop grade-appropriate teaching materials and science projects. These educational resources will be showcased at local science fairs, with the goal to inspire young minds and foster an early interest in Earth Science and coding. This project seeks to address a notable knowledge gap concerning the mechanisms behind mountain-building processes beneath the Earth's surface, known as orogenesis. The primary focus of this project is on understanding the role of reactive fluids and the thermodynamics of eclogitization in the deep crust. To accomplish this, the project aims to develop advanced models that integrate the thermodynamics of eclogitization with simulations of fluid flow. These models will enable researchers to investigate the interactions between fluids and the eclogitization process and determine the timescales associated with metamorphism and the sinking of the lithosphere. The project will consist of two interconnected numerical modeling studies. First, models of disequilibrium thermodynamics will be developed to capture the behavior of key mineral phases and reactions. These models will then be coupled with simulations of fluid flow and rock deformation. To validate and gain insights from the models, the researchers will compare the model outputs with the grain-scale to regional-scale structures observed in well-documented eclogites from Norway. This analysis will allow them to test the hypothesis that lithospheric foundering is a global phenomenon and a consequence of orogenesis. Moreover, the models will provide valuable information about the specific conditions under which eclogitization becomes thermodynamically favorable and the timescales required for significant accumulations of eclogite in the lower crust. The researchers will explore these processes across a diverse range of initial rock compositions, representing the wide variety found in the Earth's continental crust. Ultimately, the project aims to enhance our overall understanding of the complex metamorphic and metasomatic processes that occurs during mountain formation. This project was supported by both the Geophysics and the Petrology and Geochemistry programs.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.