Seismic facies response of tectonics and direction of block movement in the northeastern South China Sea  

南海东北部构造及块体运动指向的地震相响应(英文)

作　　者：陈洁[1] 钟广见[1] 刘少华 

机构地区：[1]广州海洋地质调查局,广州510760 [2]中科院地质地球物理所,北京100029

出　　处：《Applied Geophysics》2010年第4期306-314,399,共10页应用地球物理（英文版）

基　　金：the National Hi-Tech Research and Development Program of China(Grant No.2006AA09A101).

摘　　要：The close relationship between the structure,evolution,and resources environment of the South China Sea is a current research focus and also a focal point of our study.In this paper,we use regional seismic sections to analyze the relationship between seismic facies and the structure and tectonic evolution of the northeastern South China Sea and propose new points about the structure and the direction of block（land mass） motion.First,the tectonic features are clear and can be divided into five different structural units which are both linked and independent of each other.Second,it doesn＇t matter if the South China Sea basin pattern is extensional,weakly compressive,or strongly compressive,the regional tectonic stress field is unified.For the first time we find that two shallow subduction zones are recognized in the seismic profiles.All the tectonic blocks have accordion-fold-style structures,converging in the east,and the South China Sea exhibits different stages of basin development：growth, maturity,end,and termination.The block subduction and regional block dip directions are all aligned with the regional stress field.南海的构造与演化与资源环境等关系密切是本文研究重点。本文针对南海的东北部构造及其块体构造方向,利用所采集的区域地震剖面,通过解析地震相与构造及其演化的关系,提出以下观点:(1)构造分区特点明晰,可划分为五个不同构造单元,构造单元之间既有联系又相互独立;(2)南海沉积盆地无论表现为拉张-弱挤压-强挤压的何种构造格局,其区域构造应力场是统一的;(3)首次发现反射地震剖面上显示出两个浅俯冲点。每个块体构造层呈手风琴风箱式折曲并向东聚敛,体现沉积盆地从发育、成长、结束、消亡不同阶段在南海的表现,其块体俯冲方向以及块体包络区域性倾伏方向均与区域应力场方向一致。

关 键 词：Sea-floor spreading SCS shallow subduction one way drifting extrusion metamorphism accordion-style seismic facies 

分 类 号：P315.2[天文地球—地震学]