现代地质2017，Vol.31Issue(4)：662-671,10.
内蒙古中部乌拉山地区西沙德盖岩体地球化学-年代学特征及其地质意义
Geochemistry and Geochronology of West Shadegai Granites in Wulashan of Inner Mongolia and Its Geological Significance
摘要
Abstract
The West Shadegai granites in Wulashan of Inner Mongolia is located in Hadamengou molybdenum orefield,tectonically located in the west part of the northern margin of North China Craton,whose lithology is syenogranite.Geochemical characteristics show that the granite is characterized by high silicon (the mass fraction of SiO2 is 74.08％-75.95％),rich potassium (K2O/Na2O =1.20-3.39),rich alkali (K2O + Na2O =7.03％-8.46％),weakly peraluminous (mass fraction of A12O3 is 11.22％-13.06％,A/CNK =1.002-1.284).The Litman index belongs to the calc alkaline.The REEs are of enrichment of light rare earth elements,loss of heavy rare earth elements (LREE/HREE =19.84-27.83),and obvious loss of Eu (δEu =0.36-0.53).The enriched trace elements include Rb,Th,U,Pb,Zr,Hf,Sm;the loss elements include Ba,Ta,P,Ti;high field strength elements including Nb and Sr are slightly low,showing the characteristics of continental crust reformation type granite.The LA-ICP-MS 206pb/238U weighted average age of 22zircon samples from Shadegai pluton is (231 ± 0.8) Ma,belonging to Middle Triassic.According to the contrast of the mineralization age and the diagenetic age,the diagenesis and mineralization both occurred in Late Triassic,and the mineralization age is slightly less than the diagenetic age,showing the pluton belongs to the product of extensional tectonic magmatic activity after Indosinian.According to the available age data,we concluded that significant tectono-magmatic molybdenite mineralization events had ever occurred in Indosinian.关键词
西沙德盖岩体/陆壳改造型花岗岩/钼矿床/地球化学/地质年代学/印支期Key words
West Shadegai granite/continental crust reformation type granite/molybdenum deposit/geochemistry/geochronology/Indosinian分类
天文与地球科学引用本文复制引用
戴朝成,黄成,焦正,王新亮..内蒙古中部乌拉山地区西沙德盖岩体地球化学-年代学特征及其地质意义[J].现代地质,2017,31(4):662-671,10.基金项目
国家自然科学青年基金项目(41402085) （41402085）
国土资源部“大兴安岭成矿带南段地质矿产调查”项目(1212011120718). （1212011120718）
