【摘要】 由于近10年来海底天然气水合物的勘探和开采研究,海底滑坡逐渐受到关注。琼东南盆地海底滑坡一般发生于天然气水合物富集的陆架坡折带,对开发和勘探起着重要的影响作用。笔者基于前人已有二维地震资料,详细分析了南海北部琼东南盆地的海底滑坡几何变形特征。识别出3个主滑动面,为3期滑坡事件所致,而每期滑坡事件又划分出几个阶段的次级滑坡过程。研究区广泛发育滑坡陡壁、不同级次的滑动面、滑坡阶地、滑坡沟谷等典型滑坡地貌。初步估算,琼东南盆地海底滑坡面积约为2 500 km2,滑坡受陆架坡折、断裂活动、海平面下降、沉积物自身重力、海水底流改造、水合物分解等因素的综合控制。结合地层年代格架分析,提出琼东南盆地陆架坡折带滑坡活跃期集中在上新世—第四纪。更多还原

【Abstract】 Submarine landslides has been gradually attracted attentions because of exploration and exploitation of submarine gashydrate in the past decade.Submarine landslides in the Qiongdongnan basin,Northern South China Sea generally occur in continental slope where gashydrate usually accumulates.They play an important role to their development and exploration.We analyze the detailed geometric characteristics of submarine landslides in the Qiongdongnan basin based on the preexisting 2D seismic profiles to identify three major slide planes which are caused by three landslide events.Each landslide event can be divided into several secondary landslide stages.Typical landslide topography such as slide scarps,slide plane,slide terraces,slide valleys are widely developed in the study area.Based on preliminarily estimated,the Qiongdongnan submarine landslides cover an area of about 2 500 km2.The submarine landslides are controlled by continental slope,active faults,sea-level drops,gravity of sediments,seabottom flows,gas hydrate dissociation and other factors.Combined with chronostratigraphic framework,the active period of the landslides in the Qiongdongnan basin can be identified between Late Pliocene and Quaternary.更多还原