大兴安岭中段罕达盖地区早白垩世花岗岩的成因及其地质意义  

Petrogenesis of Early Cretaceous granites in Handagai area,central Great Xing’ an Range and its geological implications

作　　者：贾海明[1] 景妍 王清海 兰丽雪 井佳浩 JIA Hai-ming;JING Yan;WANG Qing-hai;LAN Li-xue;JING Jia-hao(Geological Survey of Jilin Province,Changchun 130102,China;College of Earth Sciences,Jilin University,Changchun 130061,China;International Centre for Geoscience Research and Education in Northeast Asia,Jilin University,Changchun 130026,China)

机构地区：[1]吉林省地质调查院,长春130102 [2]吉林大学地球科学学院,长春130061 [3]吉林大学东北亚国际地学研究与教学中心,长春130026

出　　处：《世界地质》2019年第4期921-930,共10页World Geology

基　　金：中国地质调查局综合研究项目(12120114085601)

摘　　要：对大兴安岭中段罕达盖岩体进行锆石U-Pb年龄、地球化学及Hf同位素研究。LA-ICP-MS锆石U-Pb定年结果显示罕达盖岩体岩浆侵位时间为早白垩世(136 Ma)。罕达盖岩体具有富硅、富碱及贫铁、镁、钙的特点,属于高钾钙碱性以及弱过铝质系列岩石。这些花岗岩富集轻稀土元素和大离子亲石元素(如K、Rb、Sr等),亏损重稀土元素与高场强元素(如Nb、Ta、Ti等)。结合岩石学和地球化学特点,罕达盖岩体属于I型花岗岩,并且其岩浆可能起源于新元古代-显生宙期间从亏损地幔中新增生地壳物质的部分熔融。综合前人研究,笔者认为大兴安岭中段早白垩世罕达盖岩体的形成与古太平洋板块的俯冲作用有关。The zircon U-Pb ages,geochemical data and Hf isotopic compositions for the Handagai pluton in central Great Xing’ an Range were analyzed in this study.The zircon LA-ICP-MS U-Pb dating indicates that Handagai pluton was emplaced in Early Cretaceous( 136 Ma).The Handagai pluton is characterized by high silica and alkalis,but low Fe2 O3,MgO and CaO contents.It belongs to high-K calc-alkaline series,and shows weakly peraluminous characteristics.It is enriched in LREEs and LILEs( e.g.,K,Rb and Sr),and depleted in HREEs and HFSEs( e.g.,Nb,Ta and Ti).Combined with the petrological and geochemical characteristics,the Handagai pluton shows I-type granite affinity,and it was probably derived from partial melting of newly accreted crustal material during Neoproterozoic-Phanerozoic.Combined with previous studies,the authors suggest that the generation of Early Cretaceous Handagai pluton in Central Great Xing’ an Range was closely related to the subduction of Paleo-Pacific Ocean.

关 键 词：兴安地块 地球化学 年代学 花岗岩 古太平洋 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]