The geometric architectures of depositional sequences in fault-depressions play an important role in the analysis of sequence stratigraphy.According to its geometric architectures

the Sahantala Formation of the Jurassic Cretaceous in Jirgalangtu Depression

Erlian Basin could be classified into ten seismic sequences of third grade

which in turn constitute three supersequences.The shapes of the sequences are box-like

wedge shape and sheet drape in ascending order.The sequence boundaries varied from bilateral fault

→

monoclinal fault overlap

→

marginal overlap types

correspounding respectively to the fracture subsidence

depression and filling stages of the basin.The Jirgalangtu Depression is composed of low level

water inflow and high level configurations and contains abrupt slope subaqueous fan system

prograding fan delta-turbidite fan system and marginal minor fan delta system.The combination of the three sequences includes retrograding

prograding and aggrading types.It is proposed in this paper that the geometric architectures of sequences could reveal the process of sequence dynamics

the deposition property and evolution process of the basin.