东南沿海及南海新生代火山作用与南海的形成演化  

Cenozoic Volcanism in the Southeast Coast of China and the South China Sea and the Formation and Evolution of the South China Sea

作　　者：赵海玲[1] 邓晋福[1] 李凯明[1] 李永华[1] 

机构地区：[1]中国地质大学,北京100083

出　　处：《地质论评》1999年第S1期809-816,共8页Geological Review

基　　金：国家攀登专项(编号SSER-111-2);国土资源部(编号9501112;9501112-04-02;9501105-03-02)资助项目

摘　　要：中国东南沿海地区和南海海域新生代火山岩系列、类型和Sr-Nd同位素特征十分相似,具有板内玄武岩的特征。根据南海扩张时代,将新生代的火山岩划分为扩张期前、扩张期和扩张期后3大阶段,并利用原生岩浆推导了软流圈岩石圈的一些深部作用特征。扩张期前(接近扩张期)和扩张期软流圈顶部埋深较浅。从扩张期前(接近扩张期)到扩张期软流圈顶部埋深变浅,隙间熔浆增加,原生岩浆的演化具有前进式裂谷火山作用的演化序列,岩石圈扩张速率变大。从扩张期到扩张期后(直至第四纪),软流圈顶部埋深逐渐变深,隙间熔浆减少,原生岩浆的演化表现出后退式裂谷火山作用的序列,岩石圈扩张速率逐渐变慢。新生代火山作用显示出的深部作用特征与南海的扩张和闭合一致,这为我们提供了南海形成和演化的深部作用证据。The rock series, rock type and Sr-Nd isotopic characteristics of the Cenozoic volcanic rocks in the South China Sea are similar to those in the southeast coast of China. On the basis of the spreading age of the South China Sea, Cenozoic volcanic rocks are divided into three stages:the pre-spreading stage, the spreading stage and the post-spreading stage. The characteristics of deep processes in the asthenosphere and lithosphere are derived from primary magma. The depth to the top of the asthenosphere in the spreading stage and the pre-spreading stage is shallower than that in the post-spreading stage. From the pre-spreading stage to the spreading stage, the depth to the top of the asthenosphere decreased, while the amount of interstitial partial melt increased. The evolution of the primary magma shows a progressive evolution sequence of rifting volcanism and the lithospheric spreading velocity became faster. From the spreading stage to the post-spreading stage, the depth to the top of the asthenosphere increased gradually, while the amount of interstitial partial melt decreased. The evolution of the primary magmas shows a retrogressive evolution sequence of rifting volcanism, and the lithospheric spreading velocity decreased gradually. The deep characteristics showing Cenozoic volcanism are consistent with the opening and closing of the South China Sea, which gives deep evidence for the formation and evolution of the South China Sea.

关 键 词：新生代火山作用 南海的形成与演化 软流圈 岩石圈 东南沿海 

分 类 号：P317[天文地球—固体地球物理学]