HR: 0800h
AN: V31C-0623    [Abstracts]
TI: High pressure solubility behaviour of KCASH minerals in hydrous solutions
AU: * Burchard, M
EM: michael.burchard@rub.de
AF: Ruhr-University of Bochum, Universitaetsstr. 150, Bochum, 44780 Germany
AU: Fockenberg, T
EM: thomas.fockenberg@rub.de
AF: Ruhr-University of Bochum, Universitaetsstr. 150, Bochum, 44780 Germany
AU: Zakhartchouk, V
EM: vitali@mineralogie.rub.de
AF: Ruhr-University of Bochum, Universitaetsstr. 150, Bochum, 44780 Germany
AU: Maresch, W V
EM: walter.maresch@rub.de
AF: Ruhr-University of Bochum, Universitaetsstr. 150, Bochum, 44780 Germany
AB: Only few experimental studies have dealt on the dissolution of minerals within complex chemical systems. These studies have been performed mainly at pressures below 0.5 GPa. An experimental campaign to determine the solubility of selected phases (natural minerals of gem quality: corundum, quartz, wollastonite, sanidine, grossular, zoisite) in pure H2O and in KOH solutions at pressures between 1.0 and 5.0 GPa was initiated. For each experiment, pure water or KOH solutions of different concentrations (~100mg) plus a fragment of the crystal (10-60mg) were enclosed in a specially designed large volume gold capsule. The experiments were carried out in a standard pressure- and temperature-controlled piston-cylinder apparatus. The weight of the fluid and crystals were carefully monitored before and after each experiment to determine the solubility of the phases by weight loss. The surface of the remaining crystals and the quenched material were checked by SEM for newly-formed crystals. Each time when theses crystals occur the results were corrected based on image processing results. Final results and the observed paragenesis were used to extract data for a simple component model to simulate KCASH fluids at pressures up to 5.0 GPa. The experiments and related thermodynamic calculations show high interaction of silicon and aluminium in the hydrous solutions, increasing the solubility of both elements. In the presence of potassium even higher interaction parameters were calculated for calcium, aluminium and silicon. The presence of potassium in the solution increases the solubility of other elements by up to 50 times. Preliminary experiments show a similar effect for sodium.
DE: 3611 Thermodynamics (0766, 1011, 8411)
DE: 3630 Experimental mineralogy and petrology
DE: 3640 Igneous petrology
DE: 3654 Ultra-high pressure metamorphism
DE: 3660 Metamorphic petrology
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005