An experimental study of phase equilibria in the systems H2O-CO2-CaCl2 and H2O-CO2-NaCl at high pressures and temperatures (500-800°C, 0.5-0.9 GPa); geological and geophysical applications

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doi: 10.1007/s00410-003-0507-5
Authors:Shmulovich, Kirill I.; Graham, Colin M.
Author Affiliations:Primary:
University of Edinburgh, School of Geo Sciences, Edinburgh, United Kingdom
Other:
Russian Academy of Sciences, Russian Federation
Volume Title:Contributions to Mineralogy and Petrology
Source:Contributions to Mineralogy and Petrology, 146(4), p.450-462. Publisher: Springer International, Heidelberg-New York, International. ISSN: 0010-7999
Publication Date:2004
Note:In English. 48 refs.; illus., incl. 4 tables
Summary:Phase equilibria in the ternary systems H2O-CO2-CaCl2 and H2O-CO2-NaCI have been determined from the study of synthetic fluid inclusions in quartz at 500 and 800 oC, 0.5 and 0.9 GPa. The crystallographic control on rates of quartz overgrowth on synthetic quartz crystals was exploited to prevent trapping of fluid inclusions prior to attainment of run conditions. In ternary systems, homogeneous fluids are H2O-rich and of extremely low salinity, but at medium to high concentrations of salts and non-polar gases fluids are unlikely to be homogeneous. The two-phase state of crustal fluids should be common. For low fluid-rock ratios the cation compositions of crustal fluids are buffered by major crustal minerals: feldspars and micas in pelites and granitic rocks, calcite (dolomite) in carbonates, and pyroxenes and amphiboles in metabasites. Fluids in pelitic and granitic rocks are Na-K rich, while for carbonate and metabasic rocks fluids are Ca-Mg-Fe rich. On lithological boundaries between silicate and carbonate rocks, or between pelites and metabasites, diffusive cation exchange of the salt components of the fluid will cause the surfaces of immiscibility to intersect, leading to unmixing in the fluid phase. Dispersion of acoustic energy at critical conditions of the fluid may amplify seismic reflections that result from different fluid densities on lithological boundaries. [G.L.B.]
Sections:Experimental mineralogy; Geochemistry
Subsections:General
Subjects:Body waves; Calcium chloride; Carbon dioxide; Chemical composition; COCORP; Crust; Elastic waves; Experimental studies; Fluid inclusions; Fluid phase; Framework silicates; Gaseous phase; Geochemistry; Geophysical methods; Geophysical surveys; High pressure; High temperature; Inclusions; Metabasite; Metaigneous rocks; Metamorphic rocks; P-T conditions; P-waves; Phase equilibria; Pressure; Quartz; Reflection methods; S-waves; Seismic methods; Seismic stratigraphy; Seismic waves; Seismology; Silica minerals; Silicates; Sodium chloride; Solubility; Surveys; Synthetic materials; Temperature; Water
Abstract Numbers:04M/1229
04M/917
Record ID:2004031404
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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