Abstract:

 Mesozoic is a new field and a new layer of hydrocarbon exploration in northern South China Sea (SCS). Its formation, evolution and distribution feature attract geologists interests consequently. The results of geological-geophysical investigation revealed that the block boundary between northern SCS and eastern South China (SC), which is Zhuwai-Taiwan strait fault zone and Lishui-HaifengQiongdongnan fault zone, is definite. Therefore, north margin of SCSTaiwan block can be considered as a part of SC activity zone, and its formation closely related to SC Caledonian tectonic cycle. The development characteristics of Mesozoic and Cenozoic were affected by suture zone and crustal subblock feature remained by Caledonian orogency between northern margin of SCS block and eastern SC block. It is also proved by the discovery of transitional strata of upper Triassiclower Jurassic, upper Jurassiclower Cretaceous, and upper CretaceousEocence in Northeastern SCS.

Key words: northern margin of South China Sea, Yangtze block, South China activity zone, Caledonian tectonic cycle, Mesozoic, Cenozoic