Abstract:

Geological characteristics show that the Xianlin iron-molybdenum ore deposit belongs to the skarn type and it is formed from the contact replacement of the postmagmatic hydrothermal solutions. There are closely relationships between the formation of the deposit and granodiorite magmatic hydrotherm. According to the altered rocks, ore structure and mineral assemblage, the deposit formation is divided into 4 mineralization stages. The zircon SHRIMP U-Pb dating results indicate that the Xianlin granodiorite were emplaced at (151.8±2.2) Ma, and the Re-Os isotopic age of molybdenite shows that the mineralization took place at (132.05±0.47) Ma. The two ages prove that mineralization events occurred in Late Jurassic and Early Cretaceous, and constraint the time of the rock- formation→mineralization, which represents the time domain of mineralization process of skarn iron-molybdenum ore-forming system in the Xianlin of Western Zhejiang.

Key words: Xianlin iron-molybdenum ore deposit, SHRIMP U-Pb dating of zircon, granodiorite, Western Zhejiang