| Abstract: | Abstract Cretaceous volcanism in the coastal region of southeastern China was characteristized by occurrence of bimodal volcanics consisting of basalts and rhyolites, the geneses of which are still controversial. Based on the fact that their isotopic compositions are similar but the Sr content of the former is much higher than that of the latter, this paper discusses the respective sources of the two end-member rocks, and concludes that basalts were derived from the subduction-related enriched upper mantle wedge and their isotopic compositions had not been affected by crustal assimilation, whereas rhyolites were formed by remelting of the old metamorphic basement, but they were mixed up with the underplating basaltic magmas to various degrees so that their Sr isotopic compositions varied significantly from the sources and tended to be homogeneous to the latter. |
