Widespread hydrothermal vents and associated volcanism record prolonged Cenozoic magmatism in the South China Sea

Abstract The continental margin of the northern South China Sea is considered to be a magma-poor rifted margin. This work uses new seismic, bathymetric, gravity, and magnetic data reveal how extensively magmatic processes have reshaped latter Widespread hydrothermal vent complexes edifices such as volcanoes, igneous sills, lava flows, associated domes are confirmed in broader area Sea. Newly identified vents crater- mound-shaped surface expressions, occur chiefly above sills volcanic edifices. Detailed stratigraphic analyses volcanoes suggest that activity took place discrete phases between early Miocene Quaternary. Importantly, occurrence close present seafloor, when accompanied by shallow fluid seepage still active, well after main volcanism previously documented literature. After combining geophysical geochemical data, this study postulates extensive post-rift magmatism linked effect mantle plume over long time interval. We propose prolonged resulted contact metamorphism carbon-rich sediments, producing large amounts along Similar expected parts margins association with CO2/CH4 heat flow release into sea water underlying strata.