中文摘要：

珠江口盆地白云凹陷北部陆坡发育着17条近似NNW-SSE走向的海底峡谷,构成了区域内的陆坡限制型 海底峡谷群.基于研究区内高密度覆盖的2D 地震资料,通过外部形态、内部结构等反射特征的描述和刻画,建立了 第四纪以来的高精度层序地层格架,将沉积充填序列划分为三个体系域,即低位体系域（ LST）、海侵体系域（ TST）和 高位体系域（ HST）.根据陆坡进积特征、垂向地层叠加样式、侵蚀特征变化、连续性强振幅同相轴的识别和空间追踪, 将高位体系域进一步划分为两个沉积旋回单元, HST- I 和 HST- II.研究表明,白云凹陷陆坡限制型海底峡谷群发育在 高位体系域晚期沉积旋回（ HST- II）中.在此基础上,分别讨论了沉积物供给、沉积物失稳作用、限制型地形和流体渗 漏作用对峡谷群形成和演化的影响.第四纪以来珠江水系携带的大量沉积物经由陆架进入到陆坡区域,为海底峡谷 群的发育和演化提供了充足的沉积物来源.在第四纪高位体系域早期水道形成的限制型“负地形”基础上,大量的沉 积物在沿着陆坡坡降方向自北向南的输送过程中发生向下的侵蚀、沉积物失稳,导致了陆坡限制型海底峡谷群的发 育.研究区内广泛分布的气烟囱构造,暗示了含气流体的垂向运移和渗漏,可能促进了海底峡谷群的进一步演化.

英文摘要：

The bathymetric map shows that there are 17 NNW-SSE trending submarine canyons in the northern slope ol the Baiyun Sag in the Pearl River Mouth Basin ’ with the heads terminated on the slope ’ composing the slope-conlined submarine canyons. Based on the high resolution 2D seismic profiles’ the Quaternary sequence stratigraphic framework was established by external morphology ’ internal structure and other reflection characters. The depositional fillings can be divided into three systems tracts ’ including LST （lowstand systems tract ’ LST） ’ TST （transgressive systems tract’ TST） and HST （highstand systems tract’ HST） .The HST could be further divided into two sedimentary units’ HST-I and HST-II’ according to the prograding styles of the slope’ the vertical stacking patterns’ the change of erosion features’ and the continuity of high-amplitude seismic reflectors. The results illustrated that’ the slope-con-fined submarine canyons were developed in the later HST sedimentary unit （HST-II）. Besides’ some factors control-ling the formation and development of canyons were also discussed ’ such as sediment supply ’ sedimentary failures ’ seafloor topographic features’ and fluids leakage. Since Quaternary ’ abundant sediments from the Pearl River in the north would be transported via shelf to slope and basinfloor’ supplying the sufficient sediments for slope-confined sub-marine canyons. Controlled by some negative paleo-topographic features formed in the earlier HST sedimentary unit （HST-I） ’ during the northward transportation of these sediments’ erosions and sedimentary failures were developed ’ inducing the formations of slope-confined submarine canyons. In the study area’ the widely distributed gas chimneys’ implied the vertical migrations and leakages of gas-bearing fluids’ which might contribute to the evolution of submarine canyons.