【摘要】 利用多波束和高分辨率地震资料,分析了东海陆坡广泛发育的海底峡谷—扇体系的沉积地层结构,讨论了海底峡谷—扇体系内部主要的沉积物搬运方式、沉积特征和典型沉积环境。结果表明,海底峡谷是上陆坡沉积物质向下搬运的主要通道。海底峡谷段上部以侵蚀作用为主,局部堆积具丘状或透镜状外形的滑塌体或滑坡体;海底扇沉积开始于海底峡谷的出口,地震剖面上具杂乱、前积或上超结构,且不同位置的扇结构亦存在差异,并被正断层错动;海底扇上发育两侧具天然堤的扇谷,细颗粒浊流物质通过溢流形成具楔状外形的越岸沉积。浊流沉积在海底峡谷的出口处十分发育,具有丘状或透镜状外形,内部呈规则或杂乱反射,是海底扇的重要组成部分。块体搬运(滑塌和滑坡)和浊流是东海陆坡海底峡谷—扇体系内主要的沉积物搬运方式,它们对陆坡地形地貌起着重要的塑造作用。海底峡谷—扇体系沉积特征及物质搬运从南向北的差异性反应了不同陆坡段物源供应、水动力条件和构造活动的不同。更多还原

【Abstract】 Based on multi-beam bathymetric and high-resolution seismic data,studies including sedimentary stratigraphic structure,transportation and typical sediment environments of the submarine canyon—fan systems in the slope of the East China Sea have been carried out.The results show that canyons on the slope are the main pathways to transport sediments from the upper to the lower part of the slope.Gullies,channels developing in the canyons and several depostional bodies indicate that the erosion domains the upper canyons section.Slumps or landslides with mound-shaped or lens-shaped are only deposited in some canyons with local flat valley bottom.Submarine fans usually developed at the exits of the canyons.They have different sediment structures at different positions,but most of them are characterized by chaotic,progradational or onlap seismic reflection configuration.The channels are pathways to transport turbidity currents.The overbank deposits with a wedge shape,mainly consisting of fine-grained sediments,usually developed along both sides of the channels.Turbidite is the main part of deposition fan.Mass wastes mainly including slumps and landslides and turbidity current are the main way of sediment transportation in canyon—fan systems and play important roles in reshaping the morphology of the submarine canyon system.Different sediment characters of the canyon-fan systems from the north to the south indicate different source supply,hydrodynamic conditions and tectonic activities.更多还原