The temporal and spatial distribution of volcanism in the South China Sea region

Cenozoic magmatism in the South China Sea, the associated continental margins, coastal South China and Indochina is reviewed. Volcanism contemporaneous with rifting and sea floor spreading in the South China Sea was very weak in the margins and adjacent areas. There was only very limited magmatic activity, most probably after the cessation of sea floor spreading. The South China Sea has non-volcanic margins. Large basement relief caused by extension formed major basins and a continental-oceanic transitional zone in the northern margin reflects high crustal rigidity during rifting and drifting. The paucity of a magma supply and presence of rigid fault blocks are unfavorable to the mantle flow model previously proposed to account for the opening of the South China Sea, which was supposedly linked to the escape of Indochina induced by Indo-Eurasia collision.