Slab Subduction and Pull Link Magmatism at Active and Passive Continental Margins

Subduction leads to voluminous arc magmatism at active continental margins; however, the potential far-field geodynamic connections with coeval magmatism along opposing passive margins, are rarely investigated. Here we report large-scale and parallel mafic dike swarms on the South Qinling passive margin, whose geochemical features record the thick and cold subcontinental lithospheric mantle beneath passive margin was gradually replaced by thin and hot one during the early Paleozoic. The subduction of the Proto-Tethys oceanic lithosphere led to arc magmatism along the active margin, shortly after the rift-related mafic dike swarms occurred along the passive margin. Subsequent to the continuous oceanic subduction including the ridge-margin collision, mantle upwelling and slab rollback eventually triggered large-scale rift-related magmatism and the opening of new ocean basin at passive margin, and also back-arc magmatism on the active margin. We highlight slab subduction and pull link the geodynamic processes at active and passive continental margins, which improves our understanding of plate tectonics. Large-scale alkali mafic dike swarms on the South Qinling passive continental margin are associated with a series of parallel faults. Based on the estimated pressures and temperatures of the mantle sources of these dike swarms, we found that the thick and cold subcontinental lithospheric mantle beneath the passive continental margin was gradually replaced by thin and hot one during the early Paleozoic. In addition, arc magmatism on the active margin would slightly precede the dike swarms in passive continental margin. We suggest that the subduction of the Proto-Tethys oceanic lithosphere led to arc magmatism along the active margin, while rift-related magmatism occurred along the passive margin of South Qinling. Subsequent to the continuous oceanic subduction including the ridge-margin collision, mantle upwelling and slab rollback increased the tensional forces on the passive margin, eventually triggering large-scale rift-related magmatism and the opening of the ocean. Thus, we suggest the slab pull associated with subduction, and mantle upwelling geodynamicaly link the active and passive continental margin magmatism and leading to the opening of new ocean basins at passive margin. Large-scale parallel mafic dike swarms on South Qinling passive continental margin record thinning of the SCLM during PaleozoicArc magmatism on the active margin of North Qinling and Erlangping Arc slightly precede the dike swarms in South QinlingSlab subduction, pull and mantle upwelling geodynamicaly link the active and passive continental margins