首页 | 本学科首页   官方微博 | 高级检索  
     检索      

青藏米巴勒地区中新世钠质方沸石(霞石)响岩中单斜辉石环带研究:对岩浆-构造演化的启示
引用本文:赵文霞,于丽芳,陈建林,郭倩,王保弟.青藏米巴勒地区中新世钠质方沸石(霞石)响岩中单斜辉石环带研究:对岩浆-构造演化的启示[J].岩石学报,2011,27(7):2073-2082.
作者姓名:赵文霞  于丽芳  陈建林  郭倩  王保弟
作者单位:1. 中山大学测试中心,广州,510275
2. 中山大学测试中心,广州510275;广东省地质局七一九地质大队肇庆526020
3. 中国科学院广州地球化学研究所,广州,510640
基金项目:本文受国家自然科学基金项目(40772046)和中国科学院重要方向性项目(KZCX2-YW-Q04)联合资助.
摘    要:在拉萨地块中部米巴勒地区产出的中新世钠质方沸石(霞石)响岩中的单斜辉石发育大量环带结构,环带结构包括正环带、反环带和韵律环带。其中正环带结构从核部到边部Mg#、MgO、Cr2O3呈逐渐降低趋势,而FeO、Na2O、Al2O3、TiO2呈逐渐升高的趋势,它反映了岩浆正常结晶的历史。反环带结构中Mg#、MgO、Cr2O3从核部到边部呈升高的趋势,FeO、Na2O、Al2O3的含量总体上呈降低趋势,本文认为响岩中单斜辉石的这种环带结构是受到了和它共存的钾质-超钾质火山岩岩浆混合或混染所致,两种岩石应是各自独立的母岩浆的结晶产物。具韵律环带结构的单斜辉石从核部到边部出现成分规律性波动,Na2O、Al2O3、TiO2、Cr2O3含量的变化在正反环带的范围内,Mg#值的变化范围较小,在正环带斑晶和基质的范围内,它是岩浆多次混合作用的结果。该地区钠质过碱性岩的出现可能指示青藏高原在这套火山岩喷发时(13~12Ma),构造体制发生了显著的改变,进入到一个典型的陆内伸展阶段。

关 键 词:环带  单斜辉石  霞石响岩  中新世  青藏高原
收稿时间:4/1/2011 12:00:00 AM
修稿时间:2011/5/28 0:00:00

The zoning structure of clinopyroxene phenocrysts in the Miocene sodium analcime (nepheline) phonolite in Mibale area, Tibet: Implications for the magmatic and tectonic evolution
ZHAO WenXi,YU LiFang,CHEN JianLin,GUO Qian and WANG BaoDi.The zoning structure of clinopyroxene phenocrysts in the Miocene sodium analcime (nepheline) phonolite in Mibale area, Tibet: Implications for the magmatic and tectonic evolution[J].Acta Petrologica Sinica,2011,27(7):2073-2082.
Authors:ZHAO WenXi  YU LiFang  CHEN JianLin  GUO Qian and WANG BaoDi
Institution:Instrumental Analysis and Research Center, Sun Yat-sen University, Guangzhou 510275, China;Instrumental Analysis and Research Center, Sun Yat-sen University, Guangzhou 510275, China;No.719 Brigade of Bureau of Geology of Guangdong Province, Zhaoqing 526020, China;Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;Instrumental Analysis and Research Center, Sun Yat-sen University, Guangzhou 510275, China;Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
Abstract:Sodium analcime (nepheline) phonolites in Mibale area of Tibetan Plateau contain abundant clinopyroxene phenocrysts which show the normal, reverse or oscillatory zoning patterns. The normal zones increase in FeO, Na2O, Al2O3 and TiO2 but decrease in Mg#, MgO, Cr2O3 from core to rim, which indicates the normal magmatic evolution of fractional crystallization. The reverse zone have increasing Mg#, MgO and Cr2O3 but decreasing FeO, Na2O and Al2O3, indicating that the sodium analcime (nepheline) phonolite had been mixed or contaminated by the ultra-potassic or potassic magmas, and that both phonolite and potassic-rich rocks might have different parental magmas. The clinopyroxenes with oscillatory zones were probably the result of multi-stage magmatic mixing since that Na2O, Al2O3, TiO2 and Cr2O3 vary between normal and reverse zone clinopyroxenes as well as Mg# within the range of the phenocryst and the matrix clinopyroxenes. The peralkaline sodium magmas erupted at 13~12Ma in the area, corresponding to a temporary tectonic transformation, which suggests a typical intracontinental extensional setting.
Keywords:Zone  Clinopyroxene  Nepheline phonolite  Miocene  Tibetan Plateau
本文献已被 CNKI 万方数据 等数据库收录!
点击此处可从《岩石学报》浏览原始摘要信息
点击此处可从《岩石学报》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号