Evolution of Palaeo-Uplift and Its Controlling on Sedimentation of Kapushaliang Group of Early Cretaceous in Western Tabei Uplift

Xu Guifen; Lin Changsong; Liu Yongfu; Sun Qi

doi:10.3799/dqkx.2016.051

Abstract：Palaeo-uplift is an important tectonic unit in the petroleum basin.The Research of palaeo-uplift distribution,its evo-lution and statement its influence on the development of sediment have important study significance for oil and gas exploration. Based on the comprehensive research of core,logging data,seismic data and outcrop,the sequence stratigraphy framework of Kapushaliang Group was established,which was divided into four third-order sequences internally.Then the palaeo-uplift dis-tribution and its evolution in each sequence developmental stages of Kapushaliang Group were reconstructed.In SQ1 period, palaeo-uplift was EW trending,across the entire work area,widening from the middle to east and west,with an erosion area of 1 946 km2 .In SQ2 period,the palaeo-uplift area was decreased and submerged in the central uplift,2 small eroded areas re-mained in the east and bigger eroded area in the west,with a total area of approximately 1 365 km2 .In SQ3 period,the palaeo-uplift area was further decreased,the east was submerged overall and the northwest residual palaeo-uplift was 899 km2 ,and the palaeo-uplift disappeared to SQ4.According to the core observation,combined with rock combination and logging data, four kinds of sedimentary system types are identified:the brainded river delta,oxidized shallow delta,beach-and-bar facies and shore-shallow lake.Finally the configuration relationship between palaeo-uplift and source-to-sink system is revealed,based on seismic data,logging,core and other analysis data,using the idea of basin analysis,and studying the factors of structure, palaeo-uplift,facies comprehensively.It is found that there are two source systems developed in the research area:the source from the palaeo-uplift to the north and south sides and source from distant southern source.The northern side near the erosion uplift area developed short provenance,which formed braided river delta deposition.With the decrease of erosion area,the brai-ded river delta distribution decreases,while the long axis provenance in the south formed the oxidized delta sedimentary sys-tem,with a trend gradually from northeast to northwest direction,and the scope expanded.In addition to supply sediment,the development of palaeo-uplift also conducive to the development of lithological and stratigraphic traps,and the sand beach-and-bar of shore-shallow lake in the south also had good potential as a lithological trap.