南海北部陆坡神狐海域沉积物失稳类型探讨

发布时间：2018-10-18 10:34

【摘要】：利用广州海洋地质调查局采集的2D和准3D地震资料,从整体形态、期次性和内部结构等方面对南海北部陆坡神狐海域内广泛发育的沉积物失稳进行了类型划分和特征描述,并将沉积物失稳的分布特征和陆坡限制型海底峡谷群的分段性进行耦合关联,进而分析沉积物失稳的空间变化规律。研究结果显示,沉积物失稳可以划分为两种类型:第一种类型位于峡谷群的下游段,几乎不受峡谷群地貌的影响,表现为多期次、内部连续和自北向南的块体运动方式,主要以"残留"的形式位于峡谷群脊部;另一种类型主要表现为沿峡谷群脊部向谷底的块体运动方式,受到峡谷群地形起伏的影响,在峡谷群头部,主要为多期次滑移体,中游段变形强度最大,滑塌体是主要的类型,而在下游段-嘴部,表现为滑移块体。第四纪以来,源自北部珠江水系充足的沉积物供给和自北向南较陡的海底地形,是沉积物失稳发育的关键控制因素;陆坡限制型海底峡谷群可能造成了沉积物的再次变形作用,使得沉积物失稳的空间变化规律与峡谷群分段性具有对应关系。此外,神狐海域含气流体的垂向运移以及水合物矿体的存在,也是研究区内沉积物失稳的重要控制因素。
[Abstract]:Based on 2D and quasi 3D seismic data collected by Guangzhou Marine Geological Survey, the types and characteristics of sediment instability in Shenhu sea area on the northern slope of the South China Sea are classified and characterized in terms of overall shape, stage and internal structure. The spatial variation of sediment instability is analyzed by coupling the distribution characteristics of sediment instability with the segmented subsea canyons of restricted type of continental slope. The results show that the sediment instability can be divided into two types: the first type is located in the downstream section of the canyon group and is almost unaffected by the geomorphology of the canyon group. In the form of "residue", it is mainly located at the ridge of the gorge group, and the other type is the block moving along the ridge of the gorge group to the valley bottom, which is affected by the topographic fluctuation of the gorge group, and at the head of the gorge group, it is mainly a multi-stage slip body. In the middle reaches, the deformation intensity is the largest, and the collapse is the main type, while in the downstream segment-mouth, it is a slip block. Since the Quaternary, sufficient sediment supply from the Pearl River system in the north and steeper seabed topography from north to south have been the key controlling factors for the development of sediment instability, and the redeformation of sediments may be caused by the continental slope restricted submarine canyons. The spatial variation of sediment instability has a corresponding relationship with the segmentation of canyons. In addition, the vertical migration of gas-bearing fluids and the presence of hydrate orebodies in Shenhu sea area are also important controlling factors for the instability of sediments in the study area.
【作者单位】：中国科学院天然气水合物重点实验室中国科学院广州能源研究所;广东省新能源和可再生能源研究开发与应用重点实验室;中国科学院大学;中山大学海洋科学学院;中国地质调查局广州海洋地质调查局;
【基金】：国家自然科学基金项目(41576048) 油气藏地质及开发工程国家重点实验室(成都理工大学)开放基金(PLC201407) 广州市珠江科技新星(201710010198) 中国石油-中国科学院科技合作项目(2015A-4813)
【分类号】：P736.2

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