PEYREBRUNE (ZN, F) LODE-DEPOSIT (SW MASSI F-CENTRAL, FRANCE) - GEOCHEMICAL CHARACTERIZATION OF FLUIDS DURING THE MESOZOIC AT THE EASTERN BORDER OF THE AQUITAINE BASIN

Fluid inclusion and stable isotope data on the Palaeozoic basement-hos ted Peyrebrune (Zn, F) lode-deposit (Albigeois region), indicate that mineralization originated from circulation of basinal-derived brines d uring distinct successive Mesozoic extensional events. These new data, set in a regional context, suggest the occurrence of two distinct eva porite-bearing sedimentary basins, now concealed by the Tertiary cover : to the south, an organic matter-rich basin leading to economic Zn-su lfide deposition, and to the north an organic matter-free basin, leadi ng to a small Cu-sulfide deposition. During the fluorite episode, the two basins differentiate by the development of the E-W fracturation: m inor in the southern basin, major in the northern one.