Abstract:The Late Mesozoic is an important tectonic period for subduction of Paleo-Pacific slab beneath East Asia. Sandstones from the Well ECSs611 closely adjoining the Haijiao Uplift from the East China Sea are focused in order to trace late Mesozoic magmatic arc in terms of records of detrital zircons. Detrital zircons are selected for U-Pb isotopic dating from Oligocene Huagang Formation (1626-1638m) and Cretaceous (1638-1689m) sandstones. Results show that the detrital zircons from Huagang Formation and Cretaceous samples are mainly magmatic zircons with some metamorphic ones that formed in two episodes of ~163Ma and ~120Ma respectively, registering two late Mesozoic magmatic-metamorphic events. These magmatic zircons which were from arc-related magmatic source are characterized by low–temperature (556~732℃), enrichment of fluid-mobile U (82~3412ppm) and high field-strength Nb depletion (0.6~13.8ppm). These magmatic zircons are continental not oceanic, while other ages form detrital zircons (since Proterozoic) are consistent with key tectonic events that the South China block underwent. It is inferred that the Haijiao uplift zone belongs to eastward extension of South China. The Haijiao-Hupijiao zone if as a magmatic arc, with units of the Fuzhou forearc basin and SW Japan-Taiwan subduction accretionary complex, together constitutes an outline of late Mesozoic continental margin of East China Sea, controlled by the subduction of paleo-Pacific slab.