CHARACTERISTICS OF THE CRETACEOUS IN THE NORTHERN SOUTH CHINA SEA AND TECTONIC IMPLICATIONS

The uplift zone in the northern South China Sea had been moving southward with time during the later Mesozoic based on the systematic study of previous data.In the time of Middle-Late Jurassic,the coast areas of Guangdong Province began to gradually uplift and to be eroded,and received lots of pyroclastic deposits,while there deposited littoral-shallow sea facies up to deep sea facies deposits in the northern south China sea.In early Cretaceous,the uplift zone further moved seawards to the south,there were some river and lacustrine deposited in the intermontane basins along the coast of Guangdong Province,and littoral-shallow sea facies in the northern South China Sea.In Late Cretaceous,the major part of the South China Sea were uplift and eroded,while the intermontane basins at the coast areas of Guangdong Province were extensive and filled with the deposits of alluvial fan,riverine and lacustrine sediments,respectively. However,there were some variegated sand and mud rocks,as well as conglomerate and evaporitic deposits in the Chaoshan Sag in Late Cretaceous,The FT age of zircon from sandstone is about 75 Ma,that means that there are some Upper Cretaceous in this sag.It is most possible that the Chaoshan Sag was a foreland basin at that time,and Reed basin,Palawan and Mindoro were located in the south or southwest of the Chaoshan Sag,as part of uplift mountains.