Experimental and Modeling Studies of the PVTX and Phase Equilibrium Properties of Crustal Fluids

地球上的天然流体影响许多过程，包括有价值的金属矿石的形成，石油的生成和积累，火山爆发的爆炸性，并可能引发大地震。这些流体的成分根据它们发生的环境而变化很大。分析地球深处天然流体的能力的最新进展表明，含有大量铁的盐在许多环境中的流体中很常见。为了充分认识和理解含铁流体在各种地质过程中所起的重要作用，有必要很好地了解这些流体在代表这些流体所处的不同地质环境的温度、压力和组成范围内的物理和化学性质。这些信息反过来又有助于地质学家更好地探索现代社会所需的宝贵金属和能源资源，并有助于火山学家和地震学家更好地评估与火山爆发和地震有关的风险。H2O-NaCl-CaCl 2-FeCl 2和H2O-NaCl-KCl-FeCl 2系统中流体在适合地壳岩浆水热系统的压力和温度条件范围内的体积和热力学性质，并建立数值模型来解释从天然流体包裹体中获得的显微测温数据。该项目代表了提高我们理解代表自然发生流体的越来越复杂的流体的能力的合乎逻辑的下一步。具体地说，这项工作将确定双流体相场的位置（即，不溶性的限制）作为压力、温度和流体组成（PTX）以及两相（液体+蒸气）场中共存相的组成的函数。临界点的位置和P-T点的轨迹沿着临界等容线，在单相流体领域的等容线，以及低温相平衡解释流体成分的基础上，流体包裹体显微测温也将被确定。这些新的数据将显着推进目前的理解地壳岩浆热液系统，并提供基本的实验数据，可用于估计复杂的含水流体在高温高压下的热力学性质。

Natural fluids that occur in the Earth affect many processes, including the formation of valuable ores of metals, the generation and accumulation of petroleum, the explosivity of volcanic eruptions, and can trigger large earthquakes. The compositions of these fluids vary widely depending on the environment in which they occur. Recent advances in the ability to analyze natural fluids from deep in the earth have shown that salts containing significant amounts of iron are common in fluids from many environments. In order to fully appreciate and understand the important role that iron-bearing fluids play in various geological processes, it is necessary to have a good understanding of the physical and chemical properties of the fluids over the range of temperatures, pressures and compositions representative of the different geological environments in which these fluids occur. This information, in turn, helps geologists to better explore for valuable metallic and energy resources required by modern society, and helps volcanologists and seismologists to better assess risks associated with volcanic eruptions and earthquakes.This project represents an experimental study to determine the phase equilibrium, volumetric and thermodynamic properties of fluids in the systems H2O-NaCl-CaCl2-FeCl2 and H2O-NaCl-KCl-FeCl2 over a range of pressure and temperature conditions appropriate to crustal magmatichydrothermal systems, and to develop numerical models to interpret microthermometric data obtained from natural fluid inclusions. This project represents a logical next step in improving our ability to understand increasingly more complex fluids that are representative of naturally occurring fluids. Specifically, this work will determine the location of the two-fluid phase field (i.e., limits of immiscibility) as a function of pressure, temperature and fluid composition (PTX), as well as the compositions of coexisting phases in the two-phase (liquid + vapor) field. The location of the critical point and the locus of P-T points along the critical isochore, isochores in the one-phase fluid fields, and low temperature phase equilibria required to interpret fluid compositions based on fluid inclusion microthermometry will also be determined. These new data will significantly advance current understanding of crustal magmatic hydrothermal systems and provide basic experimental data that may be used to estimate thermodynamic properties of complex aqueous fluids at elevated temperatures and pressures.