摘要
大兴安岭南段分布着大量花岗岩体,其成因、物源性质和构造环境对于认识该区域岩浆演化具有十分重要的意义。本文对大兴安岭南段罕苏木地区岩体进行了岩石学、主量元素、微量元素、稀土元素分析。研究结果显示,罕苏木地区岩体的岩石类型为二长花岗岩,为准铝质到弱过铝质高钾钙碱性岩石,总体表现为高硅(SiO 2:75.842%~78.27%)、高钾(K 2 O:4.84%~7.36%)、富碱(Na 2 O+K 2O:8.156%~9.648%),贫镁(MgO:0.088%~0.095%)、低钙(CaO:0.134%~0.188%)的特点。岩石轻稀土富集明显,稀土元素配分曲线程明显的右倾型,Eu(0.2~0.73)显示为强烈的负异常,δCe异常(0.99~1.41)不明显。强烈富集大离子亲石元素K、Rb等,亏损Nb、Ta、Ti等高场强元素,具有低Yb、低Sr的特点。结合区域地质研究,认为罕苏木岩体属于高分异的I型花岗岩,岩浆源区可能是来源于新生年轻地壳的部分熔融的产物,可能形成在造山后岩石圈伸展环境下,与古太平洋板块向欧亚大陆俯冲有关。
There is a large amount of granite mass in the south section of the Da Hinggan Mountains.The genesis,provenance properties and tectonic environment of this rock are very important for understanding the evolution of magma in this region.This work has made analyses of petrology,main elements,trace elements and rare earth elements of rock mass in the Hansumu area in the southern section of the Da Hinggan Mountains.Results show that the Hansumu pluton is composed of monzonitic granite,as quasi-aluminous to weak-aluminous cal-alkaline rock.Overall it is characterized by high silicon(SiO 2:75.842%~78.27%),high potassium(K 2O:4.84%~7.36%),rich alkali(Na 2O+K 2O:8.156%~9.648%),poor magnesium(MgO:0.088%~0.095%),and low calcium(CaO:0.134%~0.188%).The rock is enriched in LREE,with a right-inclined distribution pattern.Eu(0.2~0.73)shows strong negative anomalies,andδCe(0.99~1.41)anomalies are not obvious.It is enriched in LILEs such as Rb,K,depleted in HFSEs such as Nb,Ta,and Ti,with low Yb and Sr.Combined with regional geological studies,the monzonitic granite in the Hansumu area is considered to highly fractionated I-type granite.Its magma source might originate from the partial melting of juvenile crustal material,possibly formed in a post-orogenic lithospheric extensional environment,and related to the subduction of the Paleo-Asian Plate to Eurasia Plate.
作者
刘芳
田景雄
安百州
赵东升
LIU Fang;TIAN Jingxiong;AN Baizhou;ZHAO Dongsheng(School of the Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083;Geological Bureau of Ningxia Hui Autonomous Region,Yinchuan,Ningxia 750021;Ningxia Institute of Geological Survey,Yinchuan,Ningxia 750021;Ningxia Hui Autonomous Region of Geophysical and Geochemical Exploration Institute,Yinchuan,Ningxia 750001;Chifeng Institute of Geological and Mineral Exploration and Development,Chifeng,InnerMongolia 024000)
出处
《地质与勘探》
CAS
CSCD
北大核心
2019年第6期1404-1415,共12页
Geology and Exploration
基金
中国地质调查局项目“大兴安岭成矿带突泉-翁牛特地区地质矿产调查”(编号:DD20160048)和“内蒙古1∶5万民主公社第四幅地质矿产综合调查”(编号:12120115031701)
宁夏地质矿产资源勘查开发创新团队(编号:201605)资助
关键词
二长花岗岩
岩石地球化学
岩石成因
罕苏木地区
大兴安岭南段
monzonitic granite
petrogeochemistry
petrogenesis
Hansumu area
south section of Da Hinggan Mountains
作者简介
第一作者:刘芳(1981年-),女,在读博士,矿产普查与勘探专业,高级工程师,长期从事岩浆活动、矿产地质找矿及研究工作。E-mail:834414859@qq.com。
