Continental subduction belt are usually formed following by the development of oceanic subduction, so the information of oceanic subduction and continental subduction should be recorded in the continental orogen. The Dabie Orogen records Triassic continent-continent collision between the South China Block and the North China Block, but there is almost no evidence of oceanic subduction. Based on the speculation that rocks related to oceanic subduction may be covered at the bottom of the Hefei Basin or migrated
to the deep mantle during continental subduction, this work carried out detailed zircon LA-ICP-MS U-Pb dating and Lu-Hf isotope analysis for the basalt and diabase in the central Hefei Basin. The result show that both the diabase from the Dashushan and the basalt from the Xiaoshushan have obtained much late Paleozoic zircon ages, with the weighted average age of 338, 270 Ma and 349, 273 Ma, while the diabase from the Jimingshan is mainly of Early Cretaceous zircon ages. The zircon ages in these mafic igneous rocks are characterized by continuous distribution from the Paleoproterozoic to the Cretaceous. The two smallest ages indicate the time of the Cenozoic mafic magmatism, and other zircons are come from the recycling of ancient rocks. Based on the comprehensive analysis of zircon preservation under high temperature conditions and their source，it can be concluded that the late Paleozoic zircon in the Cenozoic mafic igneous rocks of the Hefei Basin comes from the magmatic rocks formed by the subduction of the PaleoTethys ocean. During the Triassic continent-continent subduction, the Paleozoic magmatic rocks were partly transported to the mantle depth, and then partially melted with the mantle during the subduction of the Cenozoic Pacific plate to form the Cenozoic mafic igneous rocks. This provides direct evidence for the occurrence of late Paleozoic oceanic subduction in the Dabie Orogen.