1 Introduction. More than a million tons of fluorite and barite occur in the barite–fluorite mineral belt of southeast Sichuan (Zhang, 1988).Previous studies of the barite–fluorite deposits in this region were mainly focused on the H, O, S and Sr isotopes (Cao et al., 1987; Chen et al., 1987; Pan & Fan, 1994, 1996), fluid inclusions (Pan & Fan, 1994), and …