Sequence Structures and Evolution Patterns of the Triassic in the Platform of Tarim Basin

Although the sedimentation and sequence stratigraphy of the Triassic from Tabei area in Tarim Basin has been studied in the past,research on the sequence structures and evolution patterns on the whole basin range is rare,especially in the depression lake basin under compressional background.Using the theories and methods of classical sequence stratigraphy and modern sedimentology,emphasizing the overall research of the whole platform area of Tarim Basin,we analyzed seismic data,logging and drilling core data of Triassic in Tarim Basin and discussed the sequence structures and evolution patterns in plateform area.The results show that plateform area of Triassic is deposited stablely in compressional background,and broad depression basin is formed in the paleocraton basin.Internal sequence structures have the feature of classic sequence stratigraphy in the gentle slope background,which have three dimensional structures.Because of wide and slow slope and shallow water in the basin,low fan body of lowstand systems tract is not much developed,and transgressive systems tract has the feature of onlap with a long distance.The wide spread range of gentle reflection is well developed in highstand systems tracts.Centers of subsidence in a single and multiple sequences move into northward is the typical insider sequence structure,which shows that sequence structures and evolution patterns are controlled by the compaction flexture,and this phenomenon is consistant with the basal deformation of sedimentation in the north and uplift in the south.