Framework of Sequence Stratigraphy,Sedimentary System and Evolution of Cretaceous Hefei Basin

According to seismic, well-logs, outcrop cores data, we identified sequence stratigraphy boundarys. Cretaceous-Paleogene strata can be recognized as 3 first-order sequence, 1 second-order sequences and 4 third-order sequences. Based on the principle of base level cycles,the author distinguished established sequence stratigraphy framework, sedimentary system setting evolution in Cretaceous-Paleogene.That is: 1) Early Cretaceous sequence series(Zhuxiang Xiangdaopu Formations): a semi-graben basin which onlapped in the west faulted in the east, developed great scale alluvial fan-alluvial plain-delta plain on the western-northern western-southern respecially. On eastern eastern-northern growth aseries fan-deltas shore semideep-deep lacustrine. 2) Late Cretaceous sequence series(Zhangqiao Formation): similar with Early Cretaceous basically,buta semi-graben basin which onlapped in the south faulted in the north more salience.3) Paleogene Sequence series(Dingyuan Formation): The north of Feizhong fault uplift since tectonic movement so that bisect the basin, Dingyuan depression on the north and Shucheng depression on the south.