Peri-granitic hydrothermal circulations and mineralization

The objective of our research is to simulate numerically hydrothermal regimes and mineralization probability (R²AI) around plutons. The first results come from simulations of some natural cases: i) Fluid flow and mineralization patterns are strongly dependent of the emplacement depth of plutons. ii) The pluton floor zone is not favorable for mineral deposition; iii) The apexes strongly modified the fluid flow and mineralization patterns; iv) The cooling phase is not the main phase of convection. Zones of ore deposits may also occur before and during the hottest phase; v) Extensional detachments faults are able to delocalize and modify fluid flows. The second results concern Tighza ore deposits. The results are: i) the probable zone of mineralization appears at the beginning of magma emplacement within the permeable zone and extends to cover the area around pluton; ii) During the cooling phase, the probable zone was reduced and restricted in the permeable zone (W1) during 0.6 Myr of cooling; iii) Application of isotopic closure temperature concept with R²AI shows that the cooling ages between mineralization in W1 veins and the intrusion are not separated by more than 0.10 Myr.