Fluid inclusions and chlorite geothermometry in Fe-Cu-Zn volcanic-hosted massive sulfide deposits of the Northern Apennine ophiolites (Italy):: preliminary results

Fluid inclusions in quartz and calcite and the mineral chemistry of chlorite in the gangue of (Fe-Cu-Zn) sulfide deposits of the Northern Apennine ophiolites (Italy) have been investigated. Quartz and calcite contain fluid inclusions in the system H2O-NaCl-CaCl2, with low salinity and homogenization temperatures clustering in three different ranges: <100degreesC, 120degrees-170degreesC and 240degrees-360degreesC. Preliminary data indicate that the highest temperatures are found preferentially in stratiform, massive ores, whereas results obtained for stockwork veins mostly reflect temperatures <170degreesC. Temperatures obtained from chlorite in stockwork veins are remarkably higher (176degrees-351degreesC). The nature of the fluid inclusions encountered so far, seem do not indicate any contribution of a magmatic source, but suggests that there was some influence by meteoric waters.