An intergrated physical and chemical model for silica transport and deposition in sub-seafloor magmatic-hydrothermal environments

地球是一个地质活跃的系统，在洋中脊扩张中心不断产生新的地壳。寒冷的海水流入海底，被加热，并与玄武岩相互作用，改变了岩石和海水的成分。因此，海洋扩张中心的热液活动对海洋化学产生了重大影响，并显著影响了海洋岩石圈的组成，这些岩石圈最终在俯冲带的地幔中循环。这些洋中脊热液系统通常与有价值的矿床的形成有关，这些矿床是铜、锌和银的重要来源。由于被喷到海底的热液流体的二氧化硅含量经常被用来指示热液系统底部（即岩浆房顶部）的温度和深度，因此本研究通过开发建模软件和计算机模拟来研究不混相对海底热液环境中二氧化硅运输和沉积的作用。工作包括将相关溶解水性物质的热力学数据纳入新开发的名为FISHES的传输代码，该代码包括沸腾（即相分离）和两相流的影响。结果应该是我们根据喷口流体化学推断海底条件和预测经济矿物产地的能力的显著提高。

The Earth is a geologically active system in which new crust is continuously being generated at mid-ocean ridge spreading centers. Cold seawater flows into the sub-seafloor, is heated, and interacts with the basalt, altering the composition of both the rocks and the seawater. As a result, hydrothermal activity at oceanic spreading centers exerts a major influence on ocean chemistry and significantly affects the composition of oceanic lithosphere that is eventually recycled back into the mantle at subduction zones. These same mid-ocean ridge hydrothermal systems are often associated with the formation of valuable mineral deposits that are important sources of copper, zinc and silver. Because the silica content of hydrothermal fluids being vented onto the seafloor is often used to indicate the temperature and depth of the base of the hydrothermal system, i.e., at the top of the magma chamber, this research examines the role of immiscibility on silica transport and deposition in the submarine hydrothermal environment through the development of modeling software and computer simulations. Work involves incorporating thermodynamic data for relevant dissolved aqueous species into a newly developed transport code called FISHES which includes the effects of boiling (i.e., phase separation) and two phase flow. The result should be a dramatic improvement of our ability to infer sub-seafloor conditions based on vent fluid chemistry and to predict where economic mineral occurrences.