【摘要】 海底峡谷在全球陆缘广泛分布,是浅海沉积物向深海运移的主要通道,对于理解深海浊流触发机制、深海沉积物的搬运模式、深海扇的发育历史和深海油气资源勘探等均具有重要意义。本文基于高分辨率高精度的多波束测深数据,首次对南海东北部海底峡谷体系进行了研究,精细刻画了高屏海底峡谷、澎湖海底峡谷、台湾浅滩南海底峡谷和东沙海底峡谷等4条大型海底峡谷的地貌特征并分析其发育控制因素。海底坡度、构造运动、海山与海丘是影响南海东北部峡谷群走向与特征的重要因素,其中,海底坡度对于峡谷上游多分支与"V"字特征有显著的控制作用;构造运动是控制高屏海底峡谷走向的因素,澎湖海底峡谷的走向则与菲律宾海板块与欧亚板块碰撞有关,东沙海底峡谷的走向则与东沙运动相关,台湾浅滩南海底峡谷上段受NW向断裂构造的控制;海山的阻挡作用造成峡谷局部走向和特征改变。海底峡谷群输送大量陆源沉积物到深海盆并形成大面积的沉积物波,海山和沉积物波的发育导致东沙海底峡谷下段"回春"和转向。更多还原

【Abstract】 Submarine canyons are widely distributed on global continental margins, they are the main channels for sediment transport from shallow sea to deep sea. Submarine canyons are of great significance for understanding the triggering mechanism of turbidity currents, the transport pattern of sediments, the evolution of deep-sea/abysmal fans, and the exploration of oil and gas resources in deep sea. Based on high-resolution multi-beam bathymetric data, this paper studies the large submarine canyon group in the northeast of the South China Sea. The morphologic characteristics and controlling factors of the four large submarine canyons, the Kaoping, the Penghu, the South Taiwan Bank and the Dongsha submarine canyons, are described in detail. Seabed slope, tectonic movement, the development of seamounts and seaknolls are important factors affecting the orientation and characteristics of the Northeastern South China Sea Canyon Group. Seabed slope has an important influence on the multi-branch and "V"-shape of the upper reaches of the canyon. The orientation of the Kaoping submarine canyon is controlled by tectonic movement, the orientation of the Penghu submarine canyon is related to the collision between the Philippine Sea Plate and the South China Sea Plate, the orientation of the Dongsha submarine canyon is related to the Dongsha tectonic movement, and the upper reaches of the South Taiwan Bank submarine canyon is controlled by the NW-SE faults. The blocking effect of the seamounts changes the local orientation and morphologic characteristics of the submarine canyons. And the submarine canyon group acts as a channel to transport large amounts of terrigenous sediments to the deep-sea basin and form a large scale of sediment waves, while the development of seamounts and sediment waves leads to the "rejuvenation" and steering of the lower reaches of the Dongsha submarine canyon.更多还原