High-pressure and high-temperature titanium solution mechanisms in silicate-saturated aqueous fluids and hydrous silicate melts

In the system Na2O-Al2O3-SiO2-H2O-TiO2, the behavior of Ti-containing structural complexes has been determined in H2O-saturated silicate melts and in coexisting silicate-saturated aqueous fluids as well as in silicate-rich supercritical fluids to 900 degrees C and 2225 MPa. Titanium speciation in aqueous fluids in the system TiO2-H2O was also characterized. All measurements were carried out in situ at the desired temperature and pressure using confocal microRaman and microFTIR spectroscopy. The experiments were carried out in an Ir-gasketed hydrothermal diamond-anvil cell (HDAC) with K-type thermocouples for temperature measurement and the Raman shift of C-13 synthetic diamond to monitor pressure.