南海中北部陆架-陆坡区新生代构造-沉积演化  

Cenozoic Tectono-Sedimentary Evolution in the Middle Part of Northern Continental Shelf-Slope Region,South China Sea

作　　者：丁巍伟[1] 黎明碧[1] 何敏 唐勇[1] 方银霞[1] 

机构地区：[1]国家海洋局海底科学重点实验室,杭州310012 [2]中海石油(中国)有限公司深圳分公司,广州510240

出　　处：《高校地质学报》2009年第3期339-350,共12页Geological Journal of China Universities

基　　金：国家重点基础研究发展计划(编号:2007CB411704);国家自然科学基金(批准号:40806023);国家海洋局基本科研业务费专项资金项目(编号:1404-10)联合资助

摘　　要：南海中北部陆架-陆坡区作为南海地区的一个重要地质构造单元,记录了大陆张裂到海盆扩张的丰富信息。通过对研究区地震剖面的解释,分析了该地区新生代的构造与沉积特征,同时通过平衡剖面恢复工作,建立了新生代演化模型。研究显示南海中北部陆架-陆坡区新生代构造演化可以分为三个阶段:古新世—始新世的裂陷阶段、渐新世—早中新世的裂陷-坳陷过渡阶段以及中中新世以来的坳陷阶段。沉积环境经历了河流-湖泊、浅海和深海的演化过程。南海北部陆缘下NW-SE方向流动的地幔流的存在使得伸展活动具有由北向南发育的机制。同时陆坡区盆地(如白云凹陷)显示出韧性伸展的特征,这与地幔上涌热岩石圈伸展引起的该区域地壳强烈韧性减薄和颈缩变形相关。The middle part of the northern continental shelf-slope region lies in the south of the Pearl River Basin.As an important structure unit of the northern continental margin of the South China Sea,it has experienced multiphase tectonic events and bears a thinned crust,upon which Cenozoic rifted-depressions with great hydrocarbon potential are developed.Several seismic profiles crossing the study area are introduced in this article.Based on the interpretations and balanced cross-section restorations of these profiles,combined with structural geology,a Cenozoic tectono-sedimentary model is established.The results show that three stages can be proposed for this region：the rift stage from Paleocene to Eocene,the rift-depression stage from Oligocene to the Early Miocene,and the depression stage after the Middle Miocene.The sedimentation environment transformed from the fluvial and lake facies to the shallow sea facies,and finally to the deep sea facies.The existence of NW-SE direction mantle flow under the continental crust in the north continental margin of South China Sea made the extension activities migrate from north to south.Results also show that the depressions（such as the Baiyun Sag）on the continental slope are featured by ductile deformation.It appears to be caused by the ductile thinning and necking of the crust in response to hot lithopheric stretching,together with mantle upwelling.

关 键 词：南海 新生代 平衡剖面恢复 构造-沉积演化 伸展方式 

分 类 号：P546[天文地球—构造地质学]