The non-sulfide ore Formation conditions of Ravar-Bafgha rea, findings of carbon and oxygen stable isotopes

The carbonate-hosted zinc-lead deposits of Ravar-Bafgh area mainly contain non-sulfide ore. In this article, we have studied the variations of carbon and oxygen isotopic ratios from separated non-sulfide minerals. The range of δ۱۳CPDB in the smithsonite varies from -۱.۴۵۶ to -۷.۲۴۸‰ and shows a good congruency with meteoric CO۲. In the hemimorphite, ۱۳CPDB values vary from -۱۷.۸۷۱ to -۲۳.۵۵۴‰ and show high enrichment of light carbon isotope. Vein-type aragonite associated with non-sulfide ore is formed under the same conditions as the smithsonite, but the calcite mineral associated with sulfide ore is formed under the same conditions as the limestone. The range of ۱۸OSMOW and ۱۸OPDB isotopic ratios is studied in the mentioned minerals. In the smithsonite, the δ۱۸OSMOW values vary from +۲۱.۸۲۱ to +۲۶.۴۴۵‰, the values of δ۱۸OPDB vary from -۶.۸۸۲ to -۸.۷۶۸‰, the values in the hemimorphite vary from +۱۶.۲۶۳ to +۱۹.۵۸۰‰ and from -۱۰.۸۷۶ to -۱۴.۱۶۰‰ for ۱۸OSMOWand ۱۸OPDB respectively. These values show that the non-sulfide minerals of these deposits are formed during the weathering of exposed sulfide ore and the fluids responsible for these processes are descending meteoric waters with minor amount of pore waters entrapped in the porosity of the carbonate host rocks.

کلیدواژه ها:

Isotope ، Carbon ، Oxygen ، Lead ، Zinc ، Ravar-Bafgh