Zircon U-Pb dating of dark rocks in the Jiawang area, Xuzhou, and diamond genesis analysis

Zircon ages of dark rocks from the Jiawang area were measured by LA-ICP-MS U-Pb dating method in this paper. On the basis of tectonic setting and magmatic activity period of the kimberlite in the North China Plate, this study analyzed the genesis of diamonds in the dark rocks and mineralization prospect in this area. The research shows that the dark rocks cover a wide range in age from the Neoproterozoic to Mesozoic and even Cenozoic, which involves almost every key magmatic activity. The diamonds in northern Xuyang diabase, which derived from the mantle magmatic crystallization, don’t have the exploring potential for diamond. Xicun kimberlite has a certain prospect for diamond exploration, but its diamond-bearing rocks are worse than Shandong kimberlite. In terms of the material composition, the Yanshanian-late Himalayan period basalts are of a certain prospect of diamond exploration. Combined with the deep geological setting, it can be concluded that this area possesses the diamond-carrying condition during uplift process of mafic rocks and the possibility of occurrence of the Cenozoic kimberite. However, high geothermal heat value is unfavorable to the formation and preservation of diamond deposits.