Insights into formation of tin ore deposits: Influence of fO2 on tin speciation in H2O-HCl fluids and effect of alkali carbonate solutions o

The aim of the proposed experiments is to provide new insights into cassiterite solubility and tin speciation in various hydrous supercritical fluids at pressures and temperatures relevant for formation of hydrothermal tin ore deposits using a hydrothermal autoclave and X-ray absorption spectroscopy. For a more comprehensive understanding of tin complexation and speciation in supercritical fluids and conclusions on cassiterite-precipitating reactions two different hypotheses will be tested. On the one hand, the experimental approach enables to determine cassiterite solubility in H2O-HCl solutions and simultaneously establish the Sn(II)/Sn(IV) ratio in the fluid as function of oxygen fugacity at high temperatures and high pressures. And on the other hand, we will study cassiterite solubility in in alkali carbonate fluids.