西北地质2017，Vol.50Issue(3)：36-46,11.
内蒙北山白云山北A型花岗岩年代学、地球化学及其地质意义
Geochronology and Geochemistry of Northern Baiyunshan Granites in the Beishan Area, Inner Mongolia, China and Their Geological Significance
摘要
Abstract
Baiyunshan orthoclase granite is located in the north of the Hongliuhe-BaiyunshanXichangjing ophiolitic mé1ange zone,there has been long controversial about the ending time of the early Paleozoic orogenic in Beishan area.In this paper,LA-ICP-MS zircon U-Pb chronology and geochemistry were studied in Baiyunshan orthoclase granite.The results show that the Baiyunshan orthoclase granite has the characteristics of high silicon,high alkali,low Al2O3,poor CaO and MgO,showing the characteristics of metaluminous-over aluminum and alkaline granite;high ∑ REE,LREE slightly enriched,LREE fractionation significant HREE fractionation obviously,obvious negative anomalies of Eu,strongly enriched in Rb,Th,U,K and other large LILE,strongly depleted in Ba,Sr,P,Ti and weak losses of Ta,Nb.10 000Ga / A1 higher,3.64～3.96,zircon saturation temperature is higher,808～ 881℃,Exhibited the feature of Atype granites.By LA-ICP-MS zircon U-Pb dating,a weighted mean 206pb / 238U age of (377.3 ± 2.1) Ma (MSWD =0.034),is considered to be the formation age of the rock,that is to say Northern Baiyunshan granites were formed in late Devonian.Based on Characteristics of out crops,geochronology,geochemistry and geological setting,the authors hold that the Northern Baiyunshan granitic pluton might be a post-orogenic or late stage orogenic pluton,which formed in the tectonic setting of transformation from collision to extension in late Devonian.The newly developed Devonian A-type granite of the Baiyun Mountain in this work is of great significance to the time of the early Paleozoic orogenic activity.关键词
A型花岗岩/地球化学/后造山/白云山北/内蒙北山Key words
A-type granite/Geochemistry/post-orogenic/Baiyunshan/Beishan分类
天文与地球科学引用本文复制引用
赵鹏彬,张继军,高云鹏,朱海平,李武杰,贺争锋..内蒙北山白云山北A型花岗岩年代学、地球化学及其地质意义[J].西北地质,2017,50(3):36-46,11.基金项目
内蒙古自治区地质勘查基金项目“内蒙古自治区阿拉善盟风化梁等四幅1∶5万区域矿产地质调查”(NMKD2014-09) （NMKD2014-09）
