Abstract:

The Beiming River iron deposits as one of major typical skarntype deposits are located in Hanxing area, southern Taihang Mountains. It was formed in the boundary between diorite intrusion and midOrdovician limestone. This paper analyzed the isotopic data of sulfur and lead for skarn and magnet ore of the deposits and discussed in further the ore source by comparison with existed isotopes data. From all of these, it is demonstrated that the iron deposits had multisources and the sulfur isotopes provided an evidence of mixed origins with ratio ranging from 12.2‰ to 16.5‰. Isotopic ratios for sulfur are influenced by the oreforming processes and environment, and the ratio range indicated that the gypsum strata in wall rock was also involved in the mineralization during the movement of the deeply derived metallogenetic fluid from the lower to the upper. In addition, the ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios of pyrite are in the ranges of 17.840-18.793 (mean value is 18.419), 15.46-15.62 (mean value is 15.56) and 37.927-39.301 (mean value is 38.730), respectively, which show that lead mainly originated from lower crust and mixed with a few from the mantle.

Key words: S and Pb isotope, oreforming material, Beiming River iron deposit, southern Taihang Mountains