CAREER: Microphysical evolution of highly sheared polymineralic rocks

板块构造理论是大多数地球科学的基础，为解释地震和火山、造山和全球气候等各种现象提供了背景。尽管它具有广泛的科学和社会重要性，但关于板块构造的基本物理机制仍有一些根本问题没有得到解答。地球上的构造表现形式与其他地体的基本区别是地球物理和行星科学中的一个重大悬而未决的问题。这项研究应用了新颖的实验方法来研究岩石在行星内部的压力和温度下是如何变形的，以帮助理解地球板块构造的起源。为了实现这些研究目标，将对地壳和地幔成分的岩石进行大应变扭转变形实验。这些实验将在PI新建的大体积扭转仪(LVT)中进行，该仪器已针对高达6 Gpa的压力和高达1300℃的温度进行了优化，用于实验研究。这些研究的重点将是多矿物岩石中不同矿物相之间的微物理相互作用。其目的是更好地了解大剪切应变如何改变现实岩石的流变性，并确定这些数据偏离对单矿物材料进行的小应变实验的条件。微观构造数据将被纳入数值模型，以模拟流变学的变化如何影响构造板块的动态演化。该项目还包括本科生岩石力学教学和研究的综合计划。很少有本科课程包含岩石力学，需要更多的曝光率来扩大这一关键领域的研究能力。PI将开发一种研究级的工作台岩石变形仪器，该仪器将被纳入几所在地球科学方面拥有强大课程的本科大学的课程。通过课程和基础设施开发，这一努力旨在扩大考虑进一步研究岩石变形实验的本科生数量。

The theory of plate tectonics is the basis for most Earth science, providing context for interpreting such diverse phenomena as earthquakes and volcanoes, mountain building, and global climate. In spite of its broad scientific and societal importance, there are still fundamental unanswered questions about the underlying physical mechanisms of plate tectonics. The basic differences between the manifestation of tectonics on Earth and other terrestrial bodies are a major outstanding question in geophysics and planetary science. This research applies novel experimental approaches to study how rocks deform at the pressures and temperatures of planetary interiors to help understand the origins of plate tectonics on Earth. To fulfill these research objectives, large strain torsional deformation experiments will be conducted on rocks of crustal and mantle composition. These experiments will be performed in the PI's newly built Large Volume Torsion apparatus (LVT), which has been optimized for experimental investigations at pressures of up to 6 GPa and temperatures of up to 1300 C. The focus of these investigations will be on the microphysical interaction between various mineral phases, in polymineralic rocks. The goal is to better understand how large shear strains modify the rheological properties of realistic rocks, and identify the conditions where these data deviate from experiments conducted to small strains on monomineralic material. Microstructural data will be incorporated into numerical models to simulate how variations in rheology influence the dynamical evolution of tectonic plates. This project also includes an integrated plan for teaching and research in rock mechanics at the undergraduate level. Few undergraduate curricula incorporate rock mechanics, and more exposure is needed to broaden research capabilities in this critical area. The PI will be developing a research-grade bench-top rock deformation apparatus that will be incorporated into the curricula of several undergraduate colleges with strong programs in Earth Science. Through curriculum and infrastructure development, this effort seeks to expand the number of undergraduate students who consider further research in experimental rock deformation.