U-Pb dating, mineral geochemistry and sulfur isotopes of the Tieshan complex in Fujian Province, southeast China: Implications for Pb-Zn polymetallic mineralization

Abstract

The Tieshan complex is located in Zhenghe area of Fujian Province (SE China), which is potassic altered with extensive Cu-Mo-Au-Pb-Zn polymetallic mineralization. U-Pb dating of zircon from granite (171.38 ± 0.55 Ma) and garnet from Pb-Zn skarn ore (176.4 ± 2.1 Ma) suggested that the magmatism occurred during the Jurassic Yanshanian orogenic event. The age of magmatic apatite from granite (196.7 ± 4.1 Ma) was older than the ore formation age. The hydrothermal apatite has higher Th-Sr-V-As-U-Pb but lower Rb-Ti-Mn contents than the magmatic apatite. The elevated positive Eu and Ce anomalies, low Ce/Y and Mn/Fe but high Sr/Y ratios in the hydrothermal apatite suggested a more oxidizing mineral-forming environment. In-situ sulfur isotopes in sulfides (−0.58 to −4.57 ‰) show a deep fluid source, and the magmatic-hydrothermal fluid may have reacted with crustal rocks and mixed with meteoric water. We suggest Pb-Zn exploration potential at depth near the Jurassic (176–171 Ma) plutons at Zhenghe.