Based on syndepositional structural slope-break types, developed in Liaohe West Depression Eogene, sequences can be divided into syndepositional fault slope-break sequence, syndepositional bent slope-break sequence, and gently slope sequence.

The study on the sequence stratigraphy of Yanchang formation of Triassic in Ordos basin shows that there exist sedimentary slope break in margin of ramp belt of the basin.

The syndepositional tectonic slope-break zone controlled the distributions of sandstone and conglomerate.

Three types of tectonic slope-break zones were developed in the study area:the fault break-zone,the single slope-break zone and the combined slope-break zone.

The study results show that the lowstand sand bodies such as incised channel filling,lowstand wedges and fans controlled by the structural slope_break zones are favorable for forming the subtle reservoirs.

The structural slope_break zone, resulting in the abrupt change of the depositional slope, is initiated by the long_term activity of syndepositional structure.

LST delta distributes below the synsedimentary faulting slope break,while fluvial delta and fan delta mainly develope in HST.