Magmatic evolution and ore-forming fluids involved in the origin of the gold/base metals mineralization in the Baia Mare province, Romania
Résumé
We chose one silicic center (Danesti dacitic dome) to characterize the magmas associated with hydrothermal ore-formingsystems before fluid extraction from the melt and hydrothermal alteration, in the major gold/polymetallic Baia Mare province (Romania). Interpretation of melt inclusion data indicates that the dacites were derived from potassium-enriched, metaluminous magmas. We suggest that the aluminous character of the residual melt (trapped as melt inclusions) may play a role in the oreforming processes, as the chemistry of these melts controls the composition of evolving magmatic-hydrothermal fluid. The study of the geochemical features of silicate melt inclusions and the determination of their water contents using the recently developed Raman spectroscopy method, also reveals that the decompression was the dominant driving force for the crystallization at this silicic center.