Based on the theories of sedimentology

sequence stratigraphy and petroleum geology

this paper identified two types of slope-break including fault slope-break and flexure slope-break on the basis of sequence framework of the Oligocene Lingshui Formation in Qiongdongnan Basin.We also documented the features of each slope-break and their control and influence on the sedimentary systems.Two kinds of sequence styles including single fault half graben-like type and step fault type are recognized in the Lingshui Formation.The former sequence style commonly occurs in a half graben basin with one main boundary fault and can be divided into a margin steep slope zone

a deep center zone and a margin gentle slope zone.While the later sequence style mainly develops in a basin under the joint control of one main boundary fault and many secondary faults parallel with the boundary fault.This paper also studied the distribution of each sequence style and its inner structure characteristics.The results indicate that the sandbodies of low system tract and high system tract are the favorable targets for future hydrocarbon exploration.