中文摘要：

基于高分辨率多波束地形与多道地震资料精细解释,发现了南海西南部陆坡区5条大型深水水道.这5条水道可分成两类：1、5号水道延伸短,横剖面呈V形,弯曲度低,属顺直水道,侵蚀作用主导;2—4号水道延伸长,横剖面呈U形,弯曲度高,属弯曲水道,侵蚀-沉积作用主导.水道走向NEE-NE,长度大于350km的有2条,宽度最大达2km,切割深度最大达150m.推测这些水道是陆源物质重力流作用形成的,是该区陆源物质通过陆架输送到南海西南次海盆的重要通道.陆坡区这些水道基本发育天然堤.在下游区域第二长的2号水道谷底明显高于周缘海底,水道-天然堤沉积已逐渐演变为朵叶沉积.这些水道的深部对应基底隆起区,说明深部构造的晚期活动控制了水道的平面位置,重力流与深部构造晚期活动共同控制了水道的形成演化.

英文摘要：

We found 5deep water channels on the SW slope of South China Sea（SCS）by highresolution multi-beam bathymetric data and multi-channel seismic data.These channels are divided into two types,the first and fifth channels are straighter with the characteristics of short extension,V-shaped on cross section,low sinuosity,indication of erosion dominance.The second,third and fourth channels are sinuous with the characteristics of long extension,U-shaped on cross section,high sinuosity,indication of erosion and deposition together.These channels trend NEE-NE,with the largest width of 2km or so and incision depth of 150 mor so.There are twochannels with the length larger than 350 km.Gravity flow may cause the formation of these channels,which can transfer terrigenous sediments from terrestrial river or continental shelf rivers into SW sub-basin of SCS.Levees develop along these channels.In the lower reaches,the thalweg of the second channel is obviously higher than surrounding seafloor,showing that channel-levee sediment is transformed to lobes sediment.The deep parts below these channels show basement highs,which suggests that later activity of deep structure controls the plane situation of these channels.Both gravity flow and deep tectonic activity control the formation and evolution of the deep water channels in SW SCS.The finding of these large sinuous channels in SW SCS is important for deep water sediment system studies, which can provide the classic cases of the channel-levee sediments.It is useful for deep water petroleum exploration and needs further researches.