Fluid types in rock crystals from quartz vein close to Hutě near Bechyně

Pure quartz crystals occurred in the vein penetrating intensely altered biotite migmatites in proximity of the eclogite body located NE from Hutě near Bechyně. Optical microthermometry has been applied on fluid inclusions (FI) in quartz. Two-phase primary inclusions contain aqueous solution, vapour phase and rarely unidentified solid phase as well (type L+V±S). Medium tempered fluids (Th = 251/270 °C) contain a little amount of CO2 and eutectic temperatures (Te = -9,5/-4,3 °C) suggests presence of sulphates and/or (hydrogen)carbonates. The overall composition of trapped fluid is H2O-MgSO4 ± Na2SO4 ± K2SO4 ± KCl ± CO2. Such not common composition of aqueous phase might be a result of interaction of fluids and ultrabasic rocks containing sulphides.Pure quartz crystals occurred in the vein penetrating intensely altered biotite migmatites in proximity of the eclogite body located NE from Hutě near Bechyně. Optical microthermometry has been applied on fluid inclusions (FI) in quartz. Two-phase primary inclusions contain aqueous solution, vapour phase and rarely unidentified solid phase as well (type L+V±S). Medium tempered fluids (Th = 251/270 °C) contain a little amount of CO2 and eutectic temperatures (Te = -9,5/-4,3 °C) suggests presence of sulphates and/or (hydrogen)carbonates. The overall composition of trapped fluid is H2O-MgSO4 ± Na2SO4 ± K2SO4 ± KCl ± CO2. Such not common composition of aqueous phase might be a result of interaction of fluids and ultrabasic rocks containing sulphides