Sedimentary evolution and petroleum geology in South China during the Early Palaeozoic

Tectonically,the present-day South China area may be divided into the Yangtze and Cathaysian landmasses,where there existed distinct sedimentary environments and depositional-filling sequences influenced by the basement attributes and tectonism from the Nanhuan onwards.On the whole,the Yangtze landmass as a cratonic basin significantly consists of epicontinental sea and restricted shallow sea environments in which stable carbonate platform deposits and black shale deposits are well organized throughout the whole area.The Cathaysian landmass appears as a rift basin in the tectonically active environment,and is mostly built up of terrigenous clastic deposits rather than unified carbonate platform deposits.The individual sedimentary environments and depositional-filling sequences cited above are responsible for the differences of petroleum geology within individual landmasses.Tremendous source rocks,excellent reservoir rocks and favourable seal rocks are well represented within the Yangtze landmass,while within the Cathaysian landmass,no better source rocks and reservoir rocks have been displayed.It follows that the future targets for the petroleum exploration in South China should focus on the Early Palaeozoic strata within the Yangtze landmass.