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，最终在俯冲带再循环回地幔。同样是这些洋中脊热液系统，往往与作为铜、锌和银重要来源的有价值矿床的形成有关。 由于排放到海底的热液流体的二氧化硅含量通常用来指示热液系统底部的温度和深度，在岩浆房的顶部，本研究通过开发模拟软件和计算机模拟，考察了海底热液环境中不可渗透性对二氧化硅迁移和沉积的作用。 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，该代码包括沸腾的影响（即，相分离）和两相流。 其结果应该是大大提高我们根据喷口流体化学性质推断海底以下状况和预测经济矿物产地的能力。