南海南北陆坡地壳拉张特征对比  

A comparison of crustal stretching characteristics between northern and southern slopes of the South China Sea

作　　者：张云帆[1] 胡登科[1,2] 王万银[3] 邱之云[3] 李付成[1] 

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]阿伯丁大学地质与石油地质系,英国阿伯丁AB243UE [3]长安大学地质工程与测绘工程学院,陕西西安710054

出　　处：《热带海洋学报》2012年第3期137-143,共7页Journal of Tropical Oceanography

基　　金：国家自然科学基金项目(No.40806022);中国科学院边缘海地质重点实验室开放课题(MSGL09-06);中国科学院南海海洋研究所青年人才领域前沿项目(SQ201010)

摘　　要：南海南北共轭边缘不仅蕴藏了丰富的油气资源,而且记录了南海扩张过程的重要构造信息。通过选取南海南北陆坡区的5条地震剖面,按照不同地壳初始流变结构计算剖面的拉张因子,通过南北结果对比与数值模拟过程揭示的信息,得到以下几点认识:1)南海北部地壳拉伸程度大于南海南部,这不仅与南海南部后期经历挤压碰撞有关,而且与中生代二者所处的构造位置不同有关;2)珠江口盆地与礼乐盆地具有不同的地壳初始状态,推测在南海共轭陆缘形成过程中,二者不相对应;3)南海南部地壳拉张因子由北向南逐渐变大,是古南海向南俯冲的体现。The conjugate continental margins of the South China Sea are being studied increasingly not only for their reserves of oil and gas but also for the data that recorded the processes of expansion of the South China Sea.In this study,five long deep-water multi-channel seismic reflection profiles from both northern and southern slopes are selected to calculate the stretching factors along the profiles based on various initial crustal rheological structures.By comparing the results and the related/respective crustal evolution processes of the margins from the numerical simulation,we propose the following.First of all,the crustal extension of the northern slope is stronger than the southern slope,representing provability of different tectonics between the two since the Mesozoic Era,the latter of which could also be related to the post-extrusions and collisions on the southern margin.Secondly,the Pearl River Basin and Liyue Basin on the northern and southern slopes,respectively, crossed by the seismic profiles,had different initial crustal structures and in turn the evolution histories of the two were inconsistent during the formation of the South China Sea conjugate margins.Moreover,the crustal stretching factor of the southern slope becomes greater toward south,showing no compliment with the principle basin expansion theories.This could be indicative to the southward subduction of the paleo-South China Sea plate.

关 键 词：共轭边缘 拉张因子 礼乐盆地 古南海 

分 类 号：P736.15[天文地球—海洋地质]