SEQUENCE STRATIGRAPHIC ANALYSIS OF THE TERTIARY IN THE QIONGDONGNAN BASIN

The Qiongdongnan basin involved from a fault basin into a downwarped basin.and is filled with very thick sediments.of this suite sediments,14 sequences can be recognized in the Lower-upper Tertiary.with 6 sequences being formed in faulting stage and 8 being formed in down warping.In faulting stage.the de velopment of sequence was mainly controlled by episodic tectonic movement,and the sequence consists of coarse clastic sediments deposited in alluvial fan,river,lake,fan-delta and clastic littoral environments.In the down-warping stage,the formation of sequence was mainly controlled by global change of sea level.and the sequence is characteristic of typical passive continental margin and includes lower systern tracts.Pro gressive system tracts and high system tracts.The lower system tracts conslsts of basln botton fan.slope fan and submarine channel sediments,and progressive and high system tracts consist of delta system,clastic littoral system,carbonate platform reef system and neurotic shelf systems.