Collaborative Research: Submarine Fluid Recharge - The Role of Anhydrite and Reactive Transport Modeling of the Endeavour Segment, Juan de Fuca Ridge

智力优势：拟议的研究目标推进我们的理解的补给区的结构和演变的胡安德富卡海岭的一个很好的探索部分，通过反应运输模型计算。 研究涉及：（1）开发模拟各种几何形状的热液循环的数值计算机模型（空间范围、补给距山脊的距离）、物理性质（孔隙度、渗透率和断层分布）和补给类型（沿着轴、横轴）;（2）使用改进的硬石膏沉淀地球化学模型，包括低温矿物沉淀的作用，竞争化学反应，动力学效应和微生物活性（硫酸盐还原）在流体补给和随后的沉积物/玄武岩-海水反应期间作为温度的函数（还将探索不同岩石成分和不同水岩比等过程），以及（3）将地球化学模型结合到热液模型中以获得2-三维反应输运模型，以进一步研究由硬石膏沉淀、玄武岩-海水反应和随后的孔隙度变化控制的热液补给的理论本质。 这项工作的重点是与高温热液喷发有关的深循环系统，并将探讨硬石膏沉淀与补给区水文演变之间的反馈。 方法包括使用有限元数值计算机建模技术，根据现场数据，在不同条件下模拟奋进段遇到的热液系统中的热量和流体输送（温度，热输出，地质结构）和其他出版的材料，并使用地球化学建模软件，以提高我们对复杂的地球化学过程的理解，通过包括低-和高温矿物沉淀/溶解，以及微生物代谢的动力学效应。更广泛的影响：该研究是马里兰州、格鲁吉亚和马萨诸塞州机构之间的多学科机构间合作，以及与塔斯马尼亚大学的国际合作。 这项工作支持了三个教师的研究，其中一个是女性，并涉及博士后的交叉培训。 它还通过与塔斯马尼亚大学分享博士后的费用来利用资金。 在这个程序中开发的模型很容易移植到其他领域的研究，如风化和土壤发育，沉积物成岩作用，石油迁移，矿石存款成因，放射性废物处理，碳封存，反应障碍的地质环境工程，温泉的地质微生物学，和极端环境中的生命。

Intellectual Merit: The proposed research targets advancing our understanding of the structure and evolution of the recharge zone on a well-explored section of the Juan de Fuca Ridge through reactive transport modeling calculations. The research involves: (1) development of numerical computer models of hydrothermal circulation that simulate a variety of geometries (spatial extent, distance of recharge from the ridge), physical properties (porosity, permeability and fault distribution) and recharge styles (along axis, cross-axis); (2) use of improved geochemical models of anhydrite precipitation including the role of low-temperature mineral precipitation, competing chemical reactions, kinetic effects and microbial activity (sulfate reduction) during fluid recharge and subsequent sediment/basalt-seawater reactions as a function of temperature (processes such as different rock composition and varying water rock ratios will also be explored), and (3) incorporation of the geochemical model into the hydrothermal model to obtain a 2-D reactive transport model to further investigate the theoretical nature of hydrothermal recharge controlled by anhydrite precipitation, basalt-seawater reactions and subsequent porosity changes. The work focuses on the deep circulation system related to high-temperature hydrothermal venting and will explore the feedback between anhydrite precipitation and the hydrologic evolution of a recharge zone. Methods include use of finite-element numerical computer modeling techniques to simulate heat and fluid transport in the hydrothermal systems encountered at the Endeavor Segment under varying conditions based on field data (temperature, heat output, geologic structure) and other published material and use of geochemical modeling software to improve our understanding of the complex geochemical processes that characterize the hydrothermal system by including effects of low- and high-temperature mineral precipitation/ dissolution, and kinetic effects with microbial metabolism. Broader Impacts: The research is a multidisciplinary inter-institutional collaboration between institutions in the states of Maryland, Georgia, and Massachusetts as well as international collaboration with the University of Tasmania. The work supports the research of three faculty, one of whom is female, and involves cross training of a postdoc. It also leverages funds by sharing the cost of a postdoc with the University of Tasmania. The models developed in this program are readily transportable to other areas of research such as weathering and soil development, sediment diagenesis, petroleum migration, ore deposit genesis, radioactive-waste disposal, carbon sequestration, reactive barriers in geoenvironmental engineering, geomicrobiology of hot springs, and life in extreme environments.