Sequence Stratigraphic Framework and Sedimentary System Evolution of Lishu Rift in Songliao Basin

Chen, Xianliang; Ji, Youliang; Fan, Tailiang

Based on the theory of sequence stratigraphy, sequence stratigraphic framework of faulted layer of Lishu rift was established by comprehensively research of seismic data, well logging data, cores and the characteristic of structure evolution. Faulted layer of Lishu rift was divided into one first-order sequences(TSq1), three second-order sequences(I-III) and seven third-order sequences(SQ1-SQ7). Also sedimentary facies were classified and sedimentary system was studied in sequence framework. Study area mainly developed alluvial fan, fan delta, nearshore subaqueous fan, braided river delta and lacustrine sedimentary systems and so on. In the sedimentary period of SQ1-SQ2, the study area has a plurality of depressions which is small and near to sediment sources, it mainly developed alluvial fan and fan delta depositional systems and locally developed volcanic rock; In the sedimentary period of SQ3-SQ4, the basin scale increased quickly and formed unified dustpan-shaped faulted basin, also sedimentary pattern changed and formed unified source direction: north and east direction sources, the study area mainly developed lake, alluvial fan and fan delta depositional systems; In the sedimentary period of SQ5-SQ6, the scale of basin reached the largest and source direction inherited SQ4, the study area mainly developed lake and braided river delta sedimentary systems; In the sedimentary period of SQ7, the basin transformed from rift to depression, sedimentary pattern changed and the study area mainly developed lake and northeast direction braided river delta sedimentary systems. The lateral and vertical evolution of sedimentary system was controlled by palaeostructure and palaeogeomorphology, and sedimentary sand bodies of SQ4-SQ6 in the slope of Lishu rift were the favorable exploring area.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013