Experimental Determination of Phase Equilibria and Thermodynamic Properties of the System H2O-CO2-NaCl

Anovitz和Labotkaevin-0106990地壳中的含水流体参与了几乎所有的地质过程，包括部分熔融、热量和溶质迁移、寄主岩石的反应和蚀变、裂缝中不溶性矿物的沉积以及岩石变形。流体参与这些过程的程度取决于其化学和运输性质。H_2 O-CO_2-NaCl体系与真实的地壳流体非常接近。了解该系统的p-V-T-x特性是至关重要的，并且显然需要在高温和高压下实验确定热物理特性，以便能够了解地壳地质过程中的流体-岩石相互作用。我们与J. Blencoe合作，提出在100至300 MPa的压力和500至800 ℃的温度下，通过实验确定H2O-CO2-NaCl体系的相关系和热力学性质。这些条件位于H2O-CO2二元临界曲线之上，跨越H2O-NaCl二元临界曲线，适用于许多地壳流体-岩石过程。我们将确定的岩盐饱和表面和活动的H2O的表面上使用的内部加热的压力容器，配备了氢服务。有了这些数据，我们将能够确定三元体系的相平衡和活性-组成关系。 研究结果将补充使用合成流体包裹体的系统的研究，并将提供必要的基本输入，以构建数学模型的热力学的H2O-CO2-NaCl系统在适当的条件下的地壳地热，变质和变形系统。

Anovitz and LabotkaEAR-0106990Aqueous fluids in the Earth's crust participate in nearly all geologic processes, including partial melting, heat and solute transport, reaction and alteration of host country rock, deposition of insoluble minerals in fractures, and rock deformation. The extent to which fluid participates in these processes depends on its chemical and transport properties. The H2O-CO2-NaCl system is a close approximation to real crustal fluids. An understanding of the p-V-T-x properties of this system is critical, and an experimental determination of the thermophysical properties at high temperatures and pressures is clearly required to be able to understand the fluid-rock interaction in crustal geologic processes. We, in collaboration with J. Blencoe, propose to determine experimentally the phase relations and thermodynamic properties of the H2O-CO2-NaCl system at pressures ranging from 100 to 300 MPa and temperatures from 500 to 800 degrees C. These conditions lie above the critical curve of the H2O-CO2 binary, span the critical curve in the H2O-NaCl binary, and are appropriate for many crustal fluid-rock processes. We will determine the halite saturation surface and the activities of H2O on the surface with the use of an internally heated pressure vessel equipped with hydrogen service. With these data, we will be able to determine the phase equilibria and the activity-composition relations for the ternary system. The results will be complementary to studies of the system that use synthetic fluid inclusions and will provide the basic input necessary to construct mathematical models of the thermodynamics of the H2O-CO2-NaCl system at conditions appropriate for crustal geothermal, metamorphic, and deformation systems.