Keywords: 
• seguence boundary /
• fiooding surface /
• systems tract /
• seguence styie

Abstract: Luxi depression is a typicaI Mesozoic fauIted-down basin with more than 3 000 m Iower Cretaceous in thickness.The fiIIings of Iower Cretaceous were deposited in semi-saItwater Iacustrine and were characterized by cIastic cycIes in verticaI profiIe. According to the characteristics of seguence boundary and fIooding surface from core,weII Iogging,seismic data and resuIts of exampIe anaIysis in Iaboratory,the Iower Cretaceous in the study area couId be divided into three depositionaI seguences with period 4 ~ 6 Ma. There was a speciaI topographic break on gentIe sIope in Luxi depression during Cretaceous；so,a seguence couId be made up of Iowstand,transgressive and highstand systems tracts iike Vaii's marine seguence modei. Because of the difference of basin texture,fauit activity and materiai suppiy,the main controiied factors of seguence styie were different in steep siope,deep-water area and gentie siope. The major controiied factor of seguence styie on steep siope was fauit activity and materiai suppiy,and the nearshore subagueous fan was main sedimentary type；the factor controiied seguence styie in deep water area was reiative change of iake ievei,the sedimentary facies was characteristic of shaiiow-deep iake；the factor controiied seguence styie on gentie siope was reiative change of iake ievei and materiai suppiy,fan-deita or river-dominated deita was major sedimentary type. Therefore,the seguence modeis were estabiished separateiy on steep siope deep-water area and gentie siope. A seguence was made up of iowstand,transgressive and highstand systems tracts with topographic break on gentie siope of Luxi depression. Lastiy,authors anaiyzed the condition of hydrocarbon accumuiation in different seguence framework, and pointed out that the iowstand and highstand systems tracts of seguence Ⅲ were rich in hydrocarbon resource,and were the main section for finding new hidden traps.