Salt effects on stable isotope partitioning and their geochemical implications for geothermal brines

摘要

It has long been recognized that dissolved salts in water can change oxygen and hydrogen isotope partitioning between water and other phases (i.e., vapor, minerals) due to the hydration of ions upon the dissolution of salts in water. However, their effects have not been well determined at elevated temperatures. We are currently conducting a series of hydrothermal experiments of the system brine-vapor or minerals to 350(degrees)C, in order to determine precisely the effects of dissolved salts abundant in brines on isotope partitioning at temperatures encountered in geothermal systems. The so-called ''isotope salt effect'' has important implications for the interpretation and modeling of isotopic data of brines and rocks obtained from geothermal fields. We will show how to use our new results of isotopic partitioning to help better evaluate energy resources of many geothermal fields.