Gold-bearing quartz veins of the Bělčice ore district, Bohemian Massif: evidence for incursion of metamorphic fluids into a granodiorite body and for isothermal mixing between two types of metamorphic fluids

Abstract

Quartz gangue at the Bělčice ore district precipitated from low-salinity (3-7 wt.% eq. NaCl) aqueous-carbonic fluids with significant admixture of CH4 (up to 15 mol. %) at 350-400 °C and 200-400 MPa.

Isotope composition of quartz and calcite gangue indicates progressively heavier oxygen of mineralizing fluids (from 9-10 ‰ to 10-14 ‰ SMOW),what suggests mixing between two types of metamorphic fluids.

Keywords

• orogenic gold
• fluid inclusions
• stable isotopes
• chlorite thermometry
• Moldanubian Zone
• Bohemian Massif
• Blatná granodiorite