Eclogitization of continental lithosphere from subduction zone devolatilization

俯冲带脱挥发分对大陆岩石圈的榴辉岩化作用

• 批准号: 2323318
• 负责人: Shi Sim
• 金额: $ 38.23万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-11-01 至 2025-10-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2323318&HistoricalAwards=false
• 关键词: Eclogitization; continental; lithosphere; subduction; zone

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.

俯冲带是一个区域，一个构造板块滑动和下沉在另一个区域，由于它们与山地建筑以及诸如地震和火山喷发等自然危害的关联，它们一直是地球科学领域的主要研究重点。提高对将这些岩石沉入地球内部的过程的理解（称为建立）对俯冲区和大陆地壳研究具有宝贵的见解。建立过程需要岩石的密度比周围的岩石更高。该项目将探索控制岩石下层岩石中岩石在矿物转化导致更大密度的过程以及该过程需要俯冲带中常见的流体介导的反应的程度。这项建模研究的结果将与挪威发现的岩石进行比较，这些岩石被认为在进行了这一致密过程后恢复了表面。该研究项目由早期职业调查员领导，他们将通过率领这项研究并为博士后科学进行心理，从而获得宝贵的经验。为了确保透明度并鼓励在该项目之外的合作，所有项目的数据和结果都将公开访问，他们的发现将在国内和国际上向各种受众群体展示。该项目将有助于培训本科研究人员，K-12科学老师和来自潜水员背景的高中生。这将通过在佐治亚理工学院为本科生（REU）计划的夏季研究经验中提供动手研究经验，并与将科学，数学和计算机（CEISMC）的教育中心合作介绍了亚特兰大都会区的K-12学生的编码和地球科学概念。佐治亚州的教师奖学金（礼物）计划将提供资金来支持K-12老师和高中生，使他们能够开发适合成绩的教学材料和科学项目。这些教育资源将在当地科学展览会上展示，目的是激发年轻人的思想并提高对地球科学和编码的早期兴趣。该项目旨在解决有关地面表面下山地建筑过程背后的机制的著名知识差距，称为造山学。该项目的主要重点是理解反应性液体的作用和对壳炎在深层地壳中的热力学。为了实现这一目标，该项目旨在开发高级模型，以将Eclogogitis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与脱落过程之间的相互作用，并确定与变质和岩石圈下沉相关的时间尺度。该项目将由两项互连的数值建模研究组成。首先，将开发出二动热动力学模型，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和岩石变形的模拟结合在一起。为了验证和从模型中获得见解，研究人员将将模型输出与晶尺度的模型输出与在挪威有据可查的以精灵中观察到的区域尺度结构进行比较。该分析将使他们能够检验以下假设：岩石圈建立是一种全球现象和造成造成的结果。此外，这些模型将提供有关在热力学上有利的特定条件的有价值的信息，以及在下层外壳中大量积累的eclogite所需的时间表。研究人员将探索各种初始岩石组成的过程，代表地球连续地壳中发现的各种多样性。最终，该项目旨在增强我们对山地形成过程中复杂的变质过程和代质过程的整体理解。该项目得到了地球物理学和质学和地球化学计划的支持。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响标准，认为通过评估被认为是宝贵的支持。