内蒙古海勒斯台正长花岗岩锆石U-Pb年代学、地球化学特征  

Zircon U-Pb Geochronology,Geochemistry of the Syenite Granite Hailesitai,Inner Mongolia

作　　者：郭雷亮 汪轩辰 王帅 李英杰 石宏杰 GUO Lei⁃liang;WANG Xuan⁃chen;WANG Shuai;LI Ying⁃jie;SHI Hong⁃jie(Hebei GEO University,Shijiazhuang 050031,China;China Science Publishing&Media Ltd.,Shijiazhuang 050031,China)

机构地区：[1]河北地质大学资源学院,河北石家庄050031 [2]中国科技出版传媒股份有限公司石家庄分公司,河北石家庄050031

出　　处：《河北地质大学学报》2020年第2期1-8,共8页Journal of Hebei Geo University

基　　金：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”(41502211);中国地质调查局项目“内蒙古1∶5万哈腊特等四幅区域地质矿产调查”(12120114064201)联合资助。

摘　　要：对海勒斯台正长花岗岩进行了锆石LA-ICP-MS U-Pb年代学及岩石地球化学特征研究,测年结果显示,该岩体年龄为133. 2±1. 3 Ma,为早白垩世。岩石地球化学分析表明,海勒斯台正长花岗岩为弱过铝质岩石,属于高钾钙碱性系列;稀土元素丰度总量较高,轻稀土富集且轻重稀土分馏较明显[(La/Yb)_N=4. 24~7. 59],表现为"右倾型"的稀土配分模式,稀土元素配分曲线为海鸥式分布,负Eu异常明显。微量元素以相对富集Rb、K等大离子亲石元素,而相对亏损Ba、Nb、Sr、P、Ti等高场强元素为特征,认为海勒斯台正长花岗岩为A型花岗岩。根据构造环境判别图解及区域地质背景,结合A型花岗岩的特征,海勒斯台正长花岗岩应形成于造山后伸展构造环境。LA-ICP-MS zircon U-Pb dating and geochemical data of Hailesitai syenogranite have been studied. The results indicate that the diagenetic age of syenogranite is( 133. 2±1. 3) Ma,belonging to Early Cretaceous. The geochemical study shows that the syenogranite belongs to high-K calc-alkaline series and high aluminum rocks. The rare earth elements are characterized by rich light rare earth elements and significant fractionation of LREE and HREE [( La/Yb)N= 4. 24 ~ 7. 59]. The REE distribution patterns are right deviated,It is characterized by a slightly right-inclined gull-wing shaped REE patterns with negative Eu anomalies. For trace elements,the syenogranites are enriched in Rb and K,but depleted in Ba,Nb,Sr,P and Ti. The granite in Hailesitai area belong to A-type granite. Based on tectonic environment discrimination diagram and tectonic environment,combined with the characteristic of A-type granite,the Hailesitai syenogranite should be formed in post-orogenic extensional tectonic environment.

关 键 词：A型花岗岩 后造山 早白垩世 地球化学 内蒙古 

分 类 号：P597.3[天文地球—地球化学]