Sedimentary Systems of the Superimposed RiftSubsidence Basin: Taking LishuiJiaojiang Sag of the East China Sea as an example

Key words: 
• LishuiJiaojiang Sag /
• Paleocene /
• superimposed riftsubsidence basin /
• sedimentary systems /
• favorable areas /

Abstract: LishuiJiaojiang Sag is the representative offshore superimposed riftsubsidence basin of China. Integrated study of well core, seismic, drilling, and logging shows that there are five sedimentary systems of the Paleocene in LishuiJiaojiang Sag: fan delta system, delta system, lake system,  system and gravity flow system. The distribution patterns of the depositional systems in space are analyzed  as  that  there was lacustrine environment in the Yueguifeng Formation, and then, strong rifting proceeded, the basin underwent a largescale transgression, sedimentary environment changed into marine environment, delta system developed in the west gentle slope which was provided by the Minzhe uplift, fan delta system developed in the east steep hill which was controlled by synsedimentary faults. Lingfeng buried hill was out of water surface in the Yueguifeng ang Lingfeng Formation, there deposited several fan delta systems and nearshore subaqueous fan systems in its both sides. Based on the research, two favorable areas are proposed as fan delta (nearshore subaqueous fan) and littoralshallow sea (lake) sand body on both sides of the Lingfeng buried hill, delta front and slumping gravity flow sand body matching fault block favorable structure in the south of the western slope of West Subsag of Lishui Sag.