Geochronology of the Xihuashan Tungsten Deposit in Southeastern China: Constraints from Re-Os and U-Pb Dating.

Xihuashan tungsten deposit is one of the earliest explored tungsten deposits in southeastern China. It is a vein type deposit genetically associated with the Xihuashan granite pluton. Here we report new dating and zircon geochemistry results. Re-Os isotopic dating for molybdenite intergrowth with wolframite in the oldest generation of the Xihuashan pluton yielded an isochron age of 157.0 ± 2.5 Ma (2σ). Zircon U-Pb laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) dating shows that the pluton crystallized at 155.7 ± 2.2 Ma (2σ). This age is similar to the molybdenite Re-Os age for the ore deposit within error. This, together with published data, suggests that the major W(Mo)-Sn mineralization occurred between 160-150 Ma in southeastern China. These deposits constitute a major part of the magmatic-metallogenic belt of eastern Nanlin. The lower Re content in molybdenite of the Xihuashan tungsten deposit shows crustal origin for the ore-forming material. The limited direct contributions from the subducting slab for the tungsten mineralization in the Nanling region suggest a change of the style of the paleo-Pacific plate beneath southeastern China. [ABSTRACT FROM AUTHOR]