Determination of PVTx properties of dense H2O+NaCl solutions to 5 GPa, 600 °C, and 50 wt% NaCl

• Applicant: Dr. Sergio Speziale
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2008 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 72046952

Knowledge of the PVTx properties of fluid systems, which approximate the behavior of natu-ral fluids, is crucial in experimental geochemistry and petrology. The primary goal of the project proposed here is to determine molar volumes of dense H2O+NaCl solutions to 5 GPa, 600°C, and 50 wt% NaCl with the maximum currently attainable precision using Brillouin spectroscopy and a modified hydrothermal diamond-anvil cell. The acquired data will extend the database by an order of magnitude in pressure and will serve as the basis to derive an empirical equation of state applicable to high fluid densities for this fundamentally important water-electrolyte system. Furthermore, we intend to determine the PT location of the liq-uidus, which is poorly known in the H2O+NaCl system at pressures above 400 MPa. Another important goal is the calibration of quartz as Raman spectroscopic pressure sensor at pres-sures above 2 GPa, which will enhance the possibilities of quantitative experimental studies at simultaneously high pressures and temperatures using hydrothermal diamond-anvil cells. Finally, Brillouin scattering measurements will allow the determination of the refractive index of H2O+NaCl solutions, in addition to the sound velocity.

• DFG Programme: Research Grants
• Participating Person: Dr. Christian Schmidt