Abstract:

Lowstand system tracts in rock salts sequence of Dongpu depression are predominantly composed of thick-massive rock salts intercalated by thin layers of mudstone and sandstone,showing in seism a continuous reflection with strong amplitude.The lacustrine transgression phase is characterized by sandstone with intercalation of thin layers of rocks salts and gravitational flow rock of deep and semi-deep lacustrine phase.Highstand system tracts are formed by thick-massive rock salts intercalated by thin layers of mudstone and sandstone.Palaeobiological fossil data collected from Shahejie Formation of Dongpu depression indicate that the development of algal-biologies,lack of freshwater biologies and mussel-shrimps appeared in layer have given a clear picture of the depositional environment of rock salts characterized chiefly and alternately by moisture and semi-arid climate,and with clastics supply even in the background of reduced deep lacustrine and semi-deep lacustrine phase.Subtle traps of Saline lake in this region are developed commonly in salt gravitational-flow fans and gravitational lenticular sandbodies of salt clastics.

Key words: saline lake sequence, salt source, response model, subtle reservoir, Dongpu depression