块体搬运沉积体系地震地貌及沉积构型:以珠江口盆地和尼日尔三角洲盆地为例

摘要

Based on the study of Pearl River Mouth basin and Niger Delta Basin,making use of high-resolution 3-D seismic data,drilling and logging data as well as regional geological data,the sedimentary architectures of the MTDs were discussed.The results show that three type MTDs are identified; slide blocks originated from the failures of continental slope(type-Ⅰ),slide blocks of submarine channel wall (type-Ⅱ) and slide-debris flow deposits complex(type-Ⅲ).The same type MTDs have certain similarities in geometry,internal texture,physical property,and stacking pattern.Type-Ⅰ displays a lobate form.There is listric slump escarpment at the tail of the slide.Rotated blocks lie above a detachment surface.Listric fans are observed within the rotated blocks.The geometry and internal texture of the type-Ⅱ are same with the type-Ⅱ.But they have different distribution range,slide direction,and strike of the slump escarpment.The linear basal scars of the type-Ⅱ represent the stronger erosion capability.The rough topography of the MTDs is caused by the inner deformation which is indicated by thrust faults.%基于珠江口盆地和尼日尔三角洲盆地的高分辨率三维地震资料和钻测井资料,对块体搬运沉积体系的沉积构型进行研究.研究结果表明:识别出陆坡滑塌形成的滑块体(Ⅰ)、水道壁滑塌形成的滑块体(Ⅱ)以及滑块体与碎屑流沉积物复合体(Ⅲ)3类块体搬运沉积体系.同一类块体搬运沉积体系的外部形态、内部结构、物理性质以及叠置样式具有一定相似性；Ⅰ类具有朵状几何外形,滑块体后部发育铲状滑塌槽.滑块体顺滑脱面滑动,并发生一定程度的旋转,内部具有铲式扇特征；Ⅱ类外部形态和内部结构与Ⅰ类的类似,但两者的分布区域、滑动方向及其所形成的滑塌槽走向差异较大；Ⅲ类具有较强的侵蚀能力,底部具有线性擦痕；其内部变形发育叠瓦逆冲构造,表面形态往往起伏不平.