Thousands of islands are scattered around in the Yellow and East China Seas

comprising Changshang Island in the north

the Southern Penghu Islands in the south and Diaoyu Dao in the east.Rock outcrops in these islands

which constitute basements of sedimentary basins

play an important part in their development.The Yellow Sea basin

with Meso-Cenozoic sediments of 6

000m thick

contains source rocks and several dozens of tectonic traps favourable to oil and gas accumulation.Being centrolled by tectonic system

it has undergone two stages of development

i.e.the early fault-bound depression and the later regional depression

both accompanied by sedimentation.The East China Sea basin

being filled with Cenozoic sediments of 10

000m thick

is rich in organic matters brought into the basin by the Yangtze and other rivers

and complicated by clusters of enormous juxtaposed tectonic belt and zones

becomes most potential for oil and gas exploration.The basin is a back-arc one

its origin and development are controlled in some extent by the interaction between the Pacific and Eurasia plates.