Magnetic recording of the Cenozoic oceanic crustal accretion and evolution of the South China Sea basin  

作　　者：LI ChunFeng SONG TaoRan 

机构地区：[1]State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China

出　　处：《Chinese Science Bulletin》2012年第24期3165-3181,共17页

基　　金：sponsored by the National Natural Science Foundation of China (91028007 and 40876022);the National Basic Research and Development Program (2007CB411702);the Research Fund for the Doctoral Program of Higher Education (20100072110036)

摘　　要：我们考察并且讨论一些在华南海(SCS ) 在磁性的数据上做的最近的科学调查结果。磁性的异例在中生代和新生代上忍受极其富有的信息构造进化。从磁性的异例计算的分析信号振幅很精确揭示的 3D 二上的中生代沉积序列的寡妇分布结合大陆人边缘，和他们也在在 SCS 海洋的外壳以内描绘以后阶段的 magmatism 和构造转变和带状配列被发现很有效。通过综合分析磁性，严肃和思考地震数据，我们在华南海大陆人边缘附近定义大陆海洋边界(圆块) ，并且发现圆块与一个转变地区与一致很好从对否定免费空气的严肃异例主要积极。COB 的这精确构画出为更好跟踪海洋的外壳导致的磁性的异例是批评的。几何上复杂的圆块和内部磁性的带状配列要求一个阵发性的洞模型，以及一个变换差错的介绍(这里作为 Zhongnan 差错制造了)在东方和西南亚盆之间在东方和西南亚盆以内，磁性的异例旁边地是相当连续的，在这些亚盆以内显示大变换差错的不存在。我们提高浅玄武岩的层经由一个通带过滤器引起的磁性的异例，并且认识到北大陆人边缘附近的多半最旧的磁性的异例根据磁性的时间规模 CK95 是 C12。在南部的大陆人边缘附近，磁性的异例是不太可认识的，异例 C12 看起来失踪。这些差别证明关于散布中心的寡妇的一种不均匀的开始式样，和北部分看起来比到南方有稍微更快传播的率。磁性的异例 C8 (M1 和 M2， 26 妈) 在海洋的盆以内代表重要磁性的边界，并且可能与在散布率和 magmatic 紧张的变化有关。为一条以前建议的山脉的磁性的证据在异例 C7 不是清楚的以后，跳。西南亚盆的年龄还得进一步被检验，最有利地与深拖引磁性的调查并且海洋钻。我们的磁性光谱最浅的居里削尖的学习表演在西南的亚盆的东方部分附近被定位，而在东方亚盆居里以We review and discuss some of the recent scientific findings made on magnetic data in the South China Sea （SCS）. Magnetic anomalies bear extremely rich information on Mesozoic and Cenozoic tectonic evolution. 3D analytical signal amplitudes com- puted from magnetic anomalies reveal very precisely relict distributions of Mesozoic sedimentary sequences on the two conjugate continental margins, and they are also found very effective in depicting later-stage magmatism and tectonic transitions and zona- tion within the SCS oceanic crust. Through integrated analyses of magnetic, gravity and reflection seismic data, we define the continent-ocean boundary. （COB） around the South China Sea continental margin, and find that the COB coincides very well with a transition zone from mostly positive to negative free-air gravity anomalies. This accurate outlining of the COB is critical for better tracing magnetic anomalies induced by the oceanic crust. The geometrically complex COB and inner magnetic zonation require the introduction of an episodic opening model, as well as a transform fault （here coined as Zhongnan Fault） between the East and Southwest Sub-basins, while within the East and Southwest Sub-basins, magnetic anomalies are rather continuous later- ally, indicating nonexistence of large transform faults within these sub-basins. We enhance magnetic anomalies caused by the shallow basaltic layer via a band-pass filter, and recognize that the likely oldest magnetic anomaly near the northern continental margin is C12 according to the magnetic time scale CK95. Near the southern continental margin, magnetic anomalies are less recognizable and the anomaly C12 appears to be missing. These differences show an asymmetrical opening style with respect to the relict spreading center, and the northern part appears to have slightly faster spreading rates than to the south. The magnetic anomalies C8 （M1 and M2, ~26 Ma） represent important magnetic boundaries within the oceanic basin, and are possibly related to change

关 键 词：中国南海 地壳增生 新生代 盆地演化 卫星磁异常 磁记录 大陆边缘 海洋地壳 

分 类 号：P736.1[天文地球—海洋地质]