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

知识价值：通过反应输运模型计算，提出的研究目标有助于我们对Juan de Fuca Ridge已勘探的部分补给带的结构和演化的理解。研究内容包括：(1)建立热液循环数值模型，模拟各种几何形状（空间范围、补给距离）、物理性质（孔隙度、渗透率和断层分布）和补给方式（沿轴、跨轴）；(2)使用改进的硬石膏降水地球化学模型，包括低温矿物降水的作用、流体补给过程中的竞争性化学反应、动力学效应和微生物活动（硫酸盐还原），以及随后的沉积物/玄武岩-海水反应作为温度的函数（不同的岩石组成和不同的水岩比等过程也将被探索）；(3)将地球化学模型与热液模型结合，得到二维反应输运模型，进一步探讨硬石膏沉淀、玄武岩-海水反应及其孔隙度变化控制热液补给的理论本质。重点研究与高温热液喷吐有关的深层循环系统，探索硬石膏降水与补给带水文演化之间的反馈关系。方法包括使用有限元数值计算机建模技术，根据现场数据（温度、热输出、温度和温度），模拟在不同条件下Endeavor段遇到的热液系统中的热量和流体输运。地质构造)和其他已发表的材料，并使用地球化学建模软件，通过包括低温和高温矿物沉淀/溶解的影响以及微生物代谢的动力学效应，提高我们对表征热液系统的复杂地球化学过程的理解。更广泛的影响：该研究是马里兰州，佐治亚州和马萨诸塞州的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。这项工作支持三名教员的研究，其中一名是女性，并涉及博士后交叉培训。它还通过与塔斯马尼亚大学分担博士后的费用来利用资金。在这个项目中开发的模型很容易转移到其他研究领域，如风化和土壤发育、沉积物成岩作用、石油运移、矿床成因、放射性废物处理、碳封存、地球环境工程中的反应屏障、温泉的地球微生物学和极端环境下的生命。

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.