塔里木西南缘新元古代辉绿岩及玄武岩的地球化学特征:新元古代超大陆(Rodinia)裂解的证据  

Geochemistry of the Neoproterozoic diabase and basalt in South of Tarim plate: Evidence for the Neoproterozoic breakup of the Rodinia super-continent in south of Tarim

作　　者：张传林[1] 叶海敏[2] 王爱国[2] 郭坤一[2] 董永观[2] 

机构地区：[1]中国科学院广州地球化学研究所,广州510640 [2]南京地质矿产研究所,南京210016

出　　处：《岩石学报》2004年第3期473-482,共10页Acta Petrologica Sinica

基　　金：国家自然科基金(编号:40303007)

摘　　要：塔里木西南缘(西昆仑北带)发育新元古代辉绿岩及玄武岩,辉绿岩侵入青白口系而被南华系超覆,玄武岩发育在南华系下部。初步的岩石地球化学研究表明,辉绿岩及玄武岩形成于大陆板内裂解背景,来自EMI型地幔源区。结合对本区格林威尔期造山事件的确定以及新元古代815Ma左右的A型片麻状花岗岩的发现,表明新元古代玄武岩喷发、辉绿岩岩墙侵入等是古塔里木板块作为Rodinia超大陆的一员在新元古代发生裂解的岩浆事件,我们推测超大陆裂解与地幔柱活动有关。Neoproterozoic diabase and basalt outcrop in south of Tarim Plate ( in north belt of Western Kunlun). The diabase intrudes into Qingbaikou system ( 1.0 similar to 0.8Ga) and is overlapped by Nanhuan rift successions (0.8 similar to 0.6Ga?). The basalt occurs in the lower part of the Nanhuan system. Geochemistry of the diabase and basalt show that they are formed in intra-continent pullaparting environment. Their source shows characteristics of EMI-type mantle. Combining the study of the Grenvillian plate subduction and collision in south of Tarim and the discovery of ca. 815Ma mantle-sourced A-type gneissoid granite, we put for-ward that the Neoproterozoic diabase and basalt are formed during the breakup of the Rodinia in south of Tarim Plate. The breakup may be connected with the action of a mantle plume just like South China Block.

关 键 词：塔里木西南 新元古代玄武岩 新元古代辉绿岩 地球化学 超大陆裂解 

分 类 号：P588.145[天文地球—岩石学] P534.3[天文地球—地质学]