Sulfur and Lead Isotope Tracing for Sources of Ore-forming Material and Ore-forming Age of the Meixian-style Pb-Zn(-Ag) Deposits in the Central Fujian Rift, South East China

The central Fujian rift is a new and important metallogenic province of the volcanogenic massive sulfide deposits in China, where several large- and middle-size Pb-Zn(-Ag) deposits were recently discovered. In order to study the sources of ore-forming material and ore-forming age, this paper analyzed the ore sulphide sulfur and lead compositions in the main five deposits and did chronological research. The result indicates that the δ34S values for ore sulfides from five major deposits range from -3.5‰ to +5.6‰ with a mean of +2.0‰, from which it is concluded that the sulphur in these deposits was derived largely from magmatic sources. Both volcanic exhalation and leaching from the host volcanic rocks are possible. Lead isotope of ores is characterized by high radioactivity with 206Pb/204Pb18.140, 207Pb/204Pb15.584 and 208Pb/204Pb38.569. Moreover, the ore sulphide lead isotope ratios are significantly more than signatures of wall-rocks, it is inferred that the ore lead was leached predominantly from hosted-volcanic rocks. According to geological features and chronologic dating, two important mineralization have been identified. One is Meso-Neoproterozoic volcanic exhalation mineralization with zircon U-Pb age, Sm-Nd isochron ages and 40Ar-39Ar plateau age of 933 to 1788Ma, the other is Yanshanian magmatic hydrothermal superimposed mineralization with a zircon SHRIMP U-Pb age and Rb-Sr isochron ages of 127 to 154Ma.