中文摘要：

南海北部陆坡区T3界面是新近系裂后期的重要地质界面（中中新世与晚中新世的交界面,约11.608Ma）,分隔了裂后期热沉降和加速沉降阶段。文中基于构造沉积背景综合分析,将南海北部陆坡区的加速沉降阶段地层充填序列划分为3大构造层,分别对应晚中新世、上新世和第四纪,采用回剥技术恢复其埋藏史,并选取1092口模拟井,采用Airy均衡模型分别计算不同时期的构造沉降速率。结果表明：1）总体上,晚中新世以来南海北部陆坡区以构造沉降为主,占70%以上;2）平面上,晚中新世以来的沉降中心集中于琼东南盆地中央拗陷带、珠江口盆地和台西南盆地的深水区域,其中台西南盆地的沉降特征最为显著,第四纪的构造沉降速率最高达190m·Ma 1;3）垂向演化上,晚中新世至上新世期间,构造沉降速率变化差异不大,有略微减小的趋势,平均构造沉降速率为70m·Ma 1,第四纪以来,构造沉降速率急剧增大,平均构造沉降速率达120m·Ma 1;4）局部特征上,构造沉降速率变化较快的部位往往发育在盆地边界、拗隆交汇及断层、褶皱发育地区,这些地区均有利于天然气水合物的聚集成藏。

英文摘要：

The Late Miocene unconformity T3 at about 11.608 Ma is an important boundary at the post-rifting stage in the northern continental slope of the South China Sea, which separated the underlying thermal subsidence and overlying accelerated subsidence. Based on the tectono-sedimentary analysis, the strata of the accelerated subsidence stage could be classified into three structural layers, the Late Miocene, the Pliocene, and the Quaternary. In this study, the Airy equilibrium model and 1092 simulation locations were used to calculate the tectonic subsidence rate along with the back-stripping technology, which could reveal the characteristics of the burial history during an accelerated subsidence stage. On the whole,＆amp;nbsp;since the Late Miocene the tectonic subsidence have played the dominant role in the northern continental slope of the South China Sea, as much as 70%. The centers of the subsidence are located in the Central Depression Belt of the Qiongdongnan Basin, the deep-water areas in the Pearl River Mouth Basin, and the Southwest Taiwan Basin; especially in the Southwest Taiwan Basin, the significant tectonic subsidence rate of the Quaternary could be 190 m·Ma-1. The evolution of the subsidence rate displayed double segment character. From the Late Miocene to Pliocene, the tectonic subsidence rate decreased slightly and the average rate was 70 m·Ma-1;since the Quaternary, the rate had a rapid increase, to as much as 120 m Ma-1. The areas that had the intraday variation of the tectonic subsidence, such as the basin boundary, join belt between upheaval and depression, and the tectonic activity areas with fault and fold could provide the helpful geological setting for the accumulation of gas hydrate.