Early Cretaceous Regional-Scale Magmatic-Hydrothermal Metallogenic System at the Southern Margin of the North China Carton

The southern margin of the North China Craton has a large-scale ore-forming event during the Mesozoic, and includes three major deposit types of lode gold (as either quartz veins or disseminated ores), porphyry Mo, and quartz vein-type Ag-Pb-Zn deposits. Ore genesis and geodynamic setting for these deposits, however, are still in a matter of debate. Geochronological studies in recent years have revealed that all of these deposits were formed during the Early Cretaceous, and show close spatial-temporal relationship with regional large-scale magmatism. In this study, we make a summary of geological features and regionally spatial-temporal distributioin of the major deposit types, and discuss their probable metal sources and possible genetic links between different deposit types. We suggest that these different types of deposits formed a giant regional magmatic-hydrothermal metallogenic system. Moreover, the mineralization event at the southern margin of the North China Craton has ages and geological features consistent with those deposits in the neighboring eastern Qinling-Dabie metallogenic belt. They were formed in the same geodynamic setting, which was controlled by the Early Cretaceous large-scale extensional events of the East China. In combination with geophysical data, such an extensional and magmatic event at a lithospheric scale was mostly likely related to the subduction of the Paleo-Pacific Plate underneath the East Asia continent. Upwelling of the magmas and the related hydrothermal fluids were extensively interacted with upper crustal rocks and shallow-derived fluids, and formed a regional scale magmatic-hydrothermal matallogenic system at the priority structures of upper crustal level.