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

海底岩浆-热液环境中二氧化硅迁移和沉积的综合物理和化学模型

• 批准号: 0928472
• 负责人: Robert Bodnar
• 金额: $ 21.57万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0928472&HistoricalAwards=false
• 关键词: intergrated; physical; chemical; model; silica

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.

地球是一个地质活跃的系统，新的地壳在洋中脊扩张中心不断生成。冷海水流入海底，被加热，并与玄武岩相互作用，改变岩石和海水的成分。 因此，海洋扩张中心的热液活动对海洋化学产生重大影响，并显着影响海洋岩石圈的组成，最终再循环回俯冲带的地幔。这些相同的洋中脊热液系统通常与有价值的矿藏的形成有关，这些矿藏是铜、锌和银的重要来源。 由于排放到海底的热液中的二氧化硅含量通常用于指示热液系统底部（即岩浆室顶部）的温度和深度，因此本研究探讨了不混溶性对二氧化硅传输和通过开发建模软件和计算机模拟，在海底热液环境中进行沉积。 工作涉及将相关溶解水物质的热力学数据纳入新开发的称为 FISHES 的传输代码中，其中包括沸腾（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产出现地点的能力得到显着提高。