珠江口盆地潮汕坳陷中生代构造变形分析  

Analysis of Mesozoic tectonic deformation in the Chaoshan Depression of Pearl River Mouth Basin

作　　者：张江阳 孙珍[1] 张素芳[3] 

机构地区：[1]中国科学院边缘海地质重点实验室,中国科学院南海海洋研究所,广东广州510301 [2]中国科学院大学,北京100049 [3]中国海洋石油总公司(中国)有限公司深圳分公司,广东广州510240

出　　处：《热带海洋学报》2014年第5期41-49,共9页Journal of Tropical Oceanography

基　　金：国家重大油气专项(2011ZX05025-003-005);国家自然科学基金-广东省联合基金项目(U1301233);国家重点基础研究发展计划项目(2009CB219401)

摘　　要：潮汕坳陷位于南海东北部陆缘,具有较厚的中生代沉积层,地层发育全,是研究南海北部中生代构造演化的最佳场所。根据研究区丰富的地震勘探资料以及最新地层解释,利用平衡剖面方法和2DMove软件对过潮汕坳陷的地震剖面进行构造分析,定量计算了潮汕坳陷及其围区中生代—新生代的地层伸缩量和相对伸缩速率。主要结论有:1)潮汕坳陷经历中生代挤压到新生代拉伸的构造环境转变,其中中生代变形以地层挠曲为主。2)潮汕坳陷中生代的地层压缩量为11%左右,为弱挤压环境。新生代地层拉伸量仅为1.8%,而周围凹陷(如潮汕坳陷南侧的靖海凹陷)地层拉伸量可达14.3%以上。说明新生代潮汕坳陷相对于周围凹陷处于极弱拉伸环境。3)坳陷晚侏罗世—早白垩世(J3—K1)挤压速率达到最大值,推测与库拉-太平洋板块快速向北西俯冲至欧亚大陆之下有关。TheChaoshan Depression located at the continental margin slope of the northern South China Sea has a thick and fully developed series of the Mesozoic strata. It is therefore the best place to study the Mesozoic tectonic evolution of the northern South China Sea. Based on plenty seismic exploration data of the study area and the most recent interpretation by specialists at theChina National Offshore Oil Corp （CNOOC）, we used 2DMove software to recover the seismic profile across the Chaoshan Depression, and calculated the amount of compression-extension and corresponding rate. The main conclusions are as follows. The Chaoshan Depression has gone through compression and extension from the Mesozoic to the Cenozoic, and the deformation is shown by the flexure of the stratum. The rate of compression of Chaoshan depression strata is around 11% in the Mesozoic, which indicates a weak compressive environment. On the other hand, the stretching of the depression is only 1.8% in the Cenozoic, while the stretching of the surrounding sags （such as Jinghai Sag in the south） could reach 14.3%, which means in the Cenozoic only the Chaoshan Depression was in a very weak extension environment. The compression rate of the depression reached maximum from late Jurassic to early Cretaceous （J3-K1）, which may be related to the rapid northwestward＆amp;nbsp;subduction of the Kula-Pacific Plate beneath the Eurasian Plate.

关 键 词：珠江口盆地 潮汕坳陷 平衡剖面 中生代 伸缩速率 

分 类 号：P736[天文地球—海洋地质]