Sequence stratigraphy of the Carboniferous-Permian coal-bearing strata in the Shengli petroleum province,Shanxi

The Carboniferous-Permian coal-bearing strata in the Shengli petroleum province, Shanxi consist of the Middle Carboniferous Benxi Formation,Upper Carboniferous Taiyuan Formation and Lower Permian Shanxi Formation.Three depositional types may be recognized,including tidal-flat,barrier island-lagoon and deltaic deposits.In the light of regional geological and palaeontological data,three isochronous surfaces are deter-mined,and two sequences and fourteen parasequences are delimited in this paper.More precisely,each sequence is made up of lowstand,transgressive and highstand systems tracts,the latter one of which is best developed.The examination of sedimentary evolu-tion of these coal-bearing strata have revealed that the Berxi Formation was accumulated in the littoral-shallow marine facies,Taiyuan Formation in the alternating terrestrial-marine facies,and Shanxi Formation in the delta facies.