期刊文献+

中国东北地区西部约500Ma泛非期孔兹岩系中斜长角闪岩原岩恢复及其构造背景 被引量:3

Reconstruction of Protholiths and Tectonic Setting of Amphibolite of Khondalite Series in West of NE China
原文传递
导出
摘要 孔兹岩系普遍发育在华北克拉通,中国东北孔兹岩系最早发现是在佳木斯地块麻山群.近期对兴安、额尔古纳地块孔兹岩系中斜长角闪岩的主量、微量、稀土元素进行了研究.斜长角闪岩的主量元素以Fe2O3(1.83%~12.37%)、MgO(4.28%~7.29%)、CaO(6.27%~10.29%)含量较高,K2O(0.56%~2.09%)、SiO2(47.06%~56.13%)含量较低为特征.微量元素Sr、Cr、Ni、Co等元素的含量较高,轻、重稀土元素分异不明显,(La/Yb)N=2~6,具有弱的负Eu异常,δEu=0.76~1.05.斜长角闪岩的原岩为玄武岩或安山质玄武岩,具有板内拉斑玄武岩的特征,因此研究区孔兹岩系形成于裂谷沉积环境.这与佳木斯地块麻山群孔兹岩系形成环境一致,表明东北地区各地块的变质基底均为孔兹岩系,其原岩均形成于裂谷沉积环境,并统一经历约500Ma泛非期变质事件.西伯利亚克拉通南缘Sayang-Baikal造山带和蒙古地体晚泛非期变质岩也经历约500Ma变质作用,因此,中亚造山带内各地块均经历约500Ma变质作用,中国东北各地块可能起源于西伯利亚克拉通南缘晚泛非期造山带的一部分. The khondalite series are usually developed in North China Craton(NCC).The Mashan Complex is firstly found to be khondalite series in NE China.We recently discover khondalite series in Xing′an and Erguna block and analyze the major,trace and rare earth elements of amphibolite of khondalite series for this study.The amphibolite are characterized with higher content of major elements like Fe2O3(1.83%-12.37%),MgO(4.28%-7.29%),and CaO(6.27%-10.29%),and lower content of K2O(0.56%-2.09%),SiO2(47.06%-56.13%).The content of trace elements such as Sr,Cr,Ni,Co is higher.The differentiation between the LREE content and the HREE content is not obvious with negative Eu anomalies shown in the chondrite standard pattern of amphibolite,and(La/Yb)N=2-6,δEu=0.76-1.05.The protoliths of amphibolite are basalt or andesitic basalt,with the characteristics of tholeiitic basalt within plate.So the protolith of khondalite series in Xing′an and Erguna block probably developed in rift valley deposit which is analogous to that of Mashan Complex.It is concluded that the basement rocks of all the blocks in NE China,including the Erguna,Xing′an,Songliao and Jiamusi-Khanka blocks,consist of khondalite series of which protolith formed in rift valley deposit and experienced about 500Ma Pan-African metamorphic event.Late Pan-African metamorphic rocks are present in Sayang-Baikal orogen along the southern margin of the Siberia Craton and the Mongolian segments of the CAOB,undergoing metamorphism at about 500Ma.All blocks in CAOB have undergone about 500Ma metamorphism,and the blocks of NE China originated possibly as part of the Late pan-African orogenic belt developed around the southern margin of the Siberia Craton.
作者 董策 周建波
出处 《地球科学(中国地质大学学报)》 EI CAS CSCD 北大核心 2013年第S1期21-30,共10页 Earth Science-Journal of China University of Geosciences
基金 国家自然科学基金项目(Nos.40739905 40872121) 国家重点基础研究发展规划项目(No.2009CB825008)
关键词 孔兹岩系 斜长角闪岩 泛非期 地球化学 原岩恢复 构造背景 中国东北 khondalite series amphibolite Pan-African geochemistry protholith reconstruction tectonic setting NE China
  • 相关文献

参考文献10

二级参考文献141

共引文献466

同被引文献125

引证文献3

二级引证文献8

相关作者

内容加载中请稍等...

相关机构

内容加载中请稍等...

相关主题

内容加载中请稍等...

浏览历史

内容加载中请稍等...
;
使用帮助 返回顶部