Basic characteristics of fluids from quartz vein at Budeč (Moldanubicum)

Fluid inclusions and oxygen isotope composition have been studied in quartz sampled from a ~30 cm thick NE-SW trending anchimonomineral quartz vein hosted by Moldanubian gneisses at Budeč. Fluid inclusions contain, in addition to aqueous fluid and vapour bubble, also three types of heterogeneously trapped solids (possibly carbonate and unknown isometric and accicular phases). The vapour-containing fluid inclusions homogenized between 95 and 215 °C. Cryometric data are rather exotic: Tf = -14 to -49 °C, Te = -8 to -38 °C, Tm of an unknown phase = -0.3 to -6.4 °C, Tm ice = 0.0 to -5.2 °C. The δ18O of quartz is 0.0 ‰ SMOW, corresponding to fluid δ18O between -11 and -22 ‰ SMOW calculated for the total range of Th values. It may be concluded that the quartz originated from a rather specific fluid system. The salt content of fluids (including chlorides, and possibly also sulphates and/or bicarbonates) may have been possibly acquired due to various low-temperature dissolution, hydrolytic and/or oxidation reactions of meteoric water and silicate rocks.Fluid inclusions and oxygen isotope composition have been studied in quartz sampled from a ~30 cm thick NE-SW trending anchimonomineral quartz vein hosted by Moldanubian gneisses at Budeč. Fluid inclusions contain, in addition to aqueous fluid and vapour bubble, also three types of heterogeneously trapped solids (possibly carbonate and unknown isometric and accicular phases). The vapour-containing fluid inclusions homogenized between 95 and 215 °C. Cryometric data are rather exotic: Tf = -14 to -49 °C, Te = -8 to -38 °C, Tm of an unknown phase = -0.3 to -6.4 °C, Tm ice = 0.0 to -5.2 °C. The δ18O of quartz is 0.0 ‰ SMOW, corresponding to fluid δ18O between -11 and -22 ‰ SMOW calculated for the total range of Th values. It may be concluded that the quartz originated from a rather specific fluid system. The salt content of fluids (including chlorides, and possibly also sulphates and/or bicarbonates) may have been possibly acquired due to various low-temperature dissolution, hydrolytic and/or oxidation reactions of meteoric water and silicate rocks