地质通报2017，Vol.36Issue(8)：1343-1358,16.
内蒙古西乌旗努和特早白垩世A型花岗岩LA-ICP-MS锆石U-Pb年龄及其地质意义
LA-ICP-MS zircon U-Pb dating of the Nuhete Early Cretaceous A-type granite in Xi Ujimqin Banner of Inner Mongolia and its geological significance
摘要
Abstract
Located along the Hegenshan colhsional orogenic suture zone in Xi Ujimqin Banner of Inner-Mongoha,the Nuhete Atype granite intruded into Late Carboniferous Meilaotewula ophiohte,Middle Permian Zhesi Formation and Late Carboniferous tonalite and consists mainly of syenogranites.The granite is geochemically characterized by high SiO2(72.92％～76.18％),K2O(4.1％～5.03％)and absolute alkali values (Na2O+K2O=8.01％～8.64％),low Al2O3,CaO,MgO,TiO2,P2O5,Sr,Ba,Eu,Ti,P values,and relatively high Ga/Al,(Na2O + K2O)/CaO,K2O/MgO,TFeO/MgO,R.b/Nb,Y/Nb,Sc/Nb ratios.It is characterized by a slightly right-inclined gull-wing shaped REE patterns with negative Eu anomalies (δ Eu=0.25～0.54).The Nuhete syenogramte exhibits the typical geochemical characteristics of aluminous A-type granites,being significantly different from I,S and M type granites in geochemistry.According to the chemical subdivision diagrams of the A-type granitoids,the Nuhete A-type granite belongs to aluminous A2-type granitoid formed and emplaced in a post-orogenic extension setting.The LA-ICP-MS zircon U-Pb dating shows that the age of the granite is 130.4 ±1.2 Ma and 130.4 ±1.4Ma,suggesting early Cretaceous.According to the temporal and spatial distribution and evolution characteristics of the ophiolites,subductional arc granitoids,collisional granites and post orogenic granitoids in the Hegenshan colhsional orogenic suture zone,the authors hold that the Hegenshan suture zone was in a post orogenic extension stage in the Early Cretaceous period.关键词
铝质A型花岗岩/LA-ICP-MS锆石U-Pb定年/早白垩世/后造山伸展环境/内蒙古西乌旗Key words
aluminous A-type granite/LA-ICP-MS zircon U-Pb dating/Early Cretaceous/post orogenic extension setting/Xi Ujimqin Banner/Inner Mongolia分类
天文与地球科学引用本文复制引用
王金芳,李英杰,李红阳,董培培..内蒙古西乌旗努和特早白垩世A型花岗岩LA-ICP-MS锆石U-Pb年龄及其地质意义[J].地质通报,2017,36(8):1343-1358,16.基金项目
国家自然科学基金项目《内蒙古西乌旗迪彦庙蛇绿岩年代学、地球化学及大地构造意义》(批准号:41502211)、中国地质调查局项目《内蒙古1∶5万沙日勒昭等四幅区域地质矿产调查》(编号:1212011120701)、《内蒙古1∶5万高力罕牧场三连等四幅区域地质矿产调查》(编号:1212011120711)和河北省教育厅项目《白音布拉格蛇绿岩岩石学和地球化学研究》(编号:ZC20165013) （批准号:41502211）
