STUDY ON THE SEQUENCE STRATIGRAPHY OF JURASSIC IN TAIBEI SAG， TUHA BASIN

The sequence stratigraphy of Jurassic in Taibei sag,Tuha Basin,is analyzed based on the comprehensive method of outcrop, logging and core analyses. The Jurassic has been divided into three first-order, seven second-order and thirteen third-order sequences. In each third-order sequence, TST is composed of regressive parasequence sets, HST is composed of transgression paracsquence sets, and the accretion parasequence sets were formed in the process of transform from regression to transgression, and LST is poorly developed in this area. Studies revedaled that the same sediment system has different facies sequence in different system tract. Delta sedimentary system shows normal facies sequence in HST, but shows inverted facies sequence in TST. Persistent thick coal beds are developed better in TST than in HST.