Abstract: Zircon U-Pb ages, whole-rock elements, Sr-Nd isotopes, and mineral O isotopes were determined for Neoproterozoic Jingtan vocanics in South Anhui. Zircon U-Pb dating indicates: the Jingtan volcanics consist of two episodes of volcanic rocks with the formation ages of 820±16 Ma and 776±10 Ma, respectively. The Jingtan volcanics show high contents of mafic components (ΣTiO2+ Fe2O3T+MgO) of 4.7% to 16.36%, LREE enrichment,moderate negative Eu anomalies, strong enrichment in large ion lithospheric elements (LILE) of K, Rb, Ba, Th and U,but pronounced negative anomalies of Sr and high field elements (HFSE) of Nb, Ta and Ti relative to the neighboring elements. Neutral whole-rock εNd(t ) values of -2.79 to -1.71 imply their derivation from relatively juvenile crust. High A/CNK ratios of 1.37 to 1.61 and high zircon δ18O values of 6.52 to 8.98‰ point to a supracrustal orign characteristic of S-type magmatic rocks. Quartz, plagioclase and K-feldspar show O isotope disequilibria when paired with zircon, suffered different degrees of post-magmatic alteration at subsolidus temperatures. On the basis of the element and isotope geochemistry, 776±10 Ma Jingtan volcanics and Shi’ershan granites are coeval. The Jingtan volcanics were directly derived from the melting of the sediments of juvenile crust, but the main source rocks for the Shi’ershan granites are about 825 Ma magmatic rocks, indirectly derived from the resetting of early Neoproterozoic juvenile crust. It is the juvenile crust in the Jiangnan orogen that was repeatedly worked due to extensional collapse of arc-continent collision orogen during the Rodinia breakup, resulting in this episode of volcanic rocks. They are neither the product of mantle superplume activity, nor the direct product of island arc magmatism, but a product of plate-rift magmatism.