Kinetics of Melt-Rock Reaction in the Mantle

熔岩反应是与地幔中熔体迁移有关的一个基本且普遍存在的过程。它负责或部分负责大洋中脊下高孔熔体通道的发育，蛇绿岩中纯橄榄岩-方辉橄榄岩-二辉橄榄岩序列的发育，岛弧观察到的岩浆多样性，以及可能在不同地质时代陆壳的生长。在这个项目中，PI将使用动力学和热力学原理、传质模型和实验室实验来更好地了解与地幔中熔体迁移相关的熔岩反应动力学。该项目将集中于三个密切相关的主题：(1)地幔熔岩反应动力学的实验研究，(2)地幔熔岩反应过程中颗粒生长和粒度分布的实验和数值研究，以及(3)通过计算机模拟多孔岩中的熔岩反应以及对三一蛇绿岩和约瑟芬蛇绿岩样品的微观分析在地质野外观测中的应用。该项目的实验室部分涉及反应溶解实验，将用于限制熔岩反应的速度和机理。颗粒生长研究将被用来限制经历反应溶解的部分地幔的渗透性。将使用实验室校准的反应速率和粒度数据进行反应流模拟，以评估地幔中熔岩-岩石反应的岩石学和地球化学后果，并探索蛇绿岩中纯橄榄岩-方辉橄榄岩-二辉橄榄岩序列的浓度梯度的意义。这项研究的结果也将为不同的地质学家群体提供有价值的信息，促进地球科学的跨学科整合。拟议的项目将为本科生提供实践经验，为高级论文提供研究机会，为研究生提供实验和计算经验。

Melt-rock reaction is a fundamental and ubiquitous process that is associated with melt migration in the Earth mantle. It is responsible or partially responsible for the development of high porosity melt channels under the mid-ocean ridge, the development of dunite-harzburgite-lherzolite sequences in ophiolites, the diversity of magmas observed in island arc, and possibly the growth of continental crust through geological times. In this project, the PI will use kinetic and thermodynamic principles, mass transfer models, and laboratory experiments to better understand the kinetics of melt-rock reaction associated with melt migration in the mantle. The project will focus on three closely related themes: (1) experimental studies of the kinetics of melt-rock reaction in the mantle, (2) experimental and numerical studies of grain growth and grain size distribution during melt-rock reaction in the mantle, and (3) applications to geological field observations through computer simulations of melt-rock reaction in porous rocks and microanalysis of samples from Trinity and Josephine ophiolites. The laboratory part of the project involves reactive dissolution experiments and will be used to constrain the rate and mechanism of melt-rock reaction. Grain growth study will be used to constrain the permeability of part of the mantle that undergoes reactive dissolution. Reactive flow modeling using laboratory calibrated reaction rates and grain size data will be used to evaluate the petrologic and geochemical consequences of melt-rock reaction in the mantle and to explore the significance of concentration gradients across the dunite-harzburgite-lherzolite sequences in ophiolites. Results from this study will also provide valuable information for a diverse group of geologists, promoting cross-discipline integration in Earth Sciences. The proposed project will provide hands on experience for undergraduates, research opportunities for senior thesis, experimental and computational experience for graduate students.