内蒙古阿巴嘎旗奥陶纪岩体的发现及地质意义  

Discovery of Ordovician pluton in Abaga Banner, Inner Mongolia and its geological significance

作　　者：赵利刚[1] 冉皞[2] 张庆红[3] 李承东[1] 王惠初[1] 张阔[1] 许雅雯[1] 侯可军[4] 

机构地区：[1]天津地质矿产研究所,天津300170 [2]中国地质大学地球科学与资源学院,北京100083 [3]河北省地矿局第十一地质大队,河北邢台054000 [4]中国地质科学院矿产资源研究所,北京100037

出　　处：《世界地质》2012年第3期451-461,共11页World Geology

基　　金：国土资源大调查项目(1212010811004);国家自然科学基金(40972037)项目联合资助

摘　　要：阿巴嘎旗格日敖包岩体位于贺根山断裂带北侧,为一个复式岩体,由石英闪长岩、花岗闪长岩和黑云母二长花岗岩组成,主体为二长花岗岩。采用LA--MC--ICP--MS锆石U--Pb定年方法,获得黑云母二长花岗岩206Pb/238U年龄为449±3.0 Ma,形成时代为晚奥陶世。岩石为高钾钙碱性系列,轻稀土富集,微量元素Ba、Sr、Nb、Ta、P、Ti亏损,Rb、Th、U、K、Nd、Zr等元素富集,表明其形成于活动大陆边缘环境。其形成可能与苏尼特左旗南侧俯冲事件有关。Geri Obo complex pluton in Abaga Banner is located in northern Hegenshan fault belt,and consists of quartz diorite,granodiorite and biotite monzogranite,in which the monzogranite is the major rocks.By LA——MC——ICP——MS zircon U——Pb dating,the monzogranite 206Pb/238U age was 449±3.0 Ma,showing the Late Ordovician.Geri Obo pluton had high-K calc-alkaline characteristics,and enriched in LREE.The trace elements were depleted in Ba,Sr,Nb,Ta,P,Ti,but enriched in Rb,Th,U,K,Nd and Zr,showing Geri Obo pluton formed in active continental margins,and might be related to the subduction event in southern Sonid zuoqi.

关 键 词：内蒙古 阿巴嘎旗 格日敖包 贺根山断裂北侧 奥陶纪侵入岩 早古生代活动大陆边缘 

分 类 号：P581[天文地球—岩石学] P588.121[天文地球—地质学]