Precise Re-Os Dating of Molybdenite from the Northern Dabie Molybdenum Belt in Central China and its Geodynamic Implications

Abstract

The Dabie orogen of east-central China marks the boundary between the North China and Yangtze Cratons, and is characterized by juxtaposition of the ~400Ma Tongbai metamorphic belt and the ~220Ma South Qinling-Dabie metamorphic belt. The Triassic collision between the North China and Yangtze Cratons which generated numerous granitoid intrusions such as the Shangcheng, Xingxian and Lingshan intrusions, and other small stocks, such as Tangjiaping, Dayinjian, Mushan and so on. Those shallow-emplaced granite porphyries are closely related to porphyry-skarn Mo and Mo-W deposites, forming the Dabie molybdenum metallogenic belt. Molybdenum deposits occur in the endo- and exocontact zones of the porphyry, include with three major types of Mo mineral systems, i.e., porphyry, less porphyry-skarn and vein-type. The ore-forming ages of the molybdenum deposits in Dabie area are mainly cluster 127.8±0.9~113.1±7.9Ma. The pulse is the product of the transformation of the tectonic regime from NS- to nearly EW-directions in East China.