| 内蒙古敖汉旗克力代岩体锆石U-Pb年代及地球化学 |
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| 引用本文： | 罗龙,;孙国胜,;苏蓉,;孙珍军.内蒙古敖汉旗克力代岩体锆石U-Pb年代及地球化学[J].世界地质,2014,33(2):299-310. |
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| 作者姓名： | 罗龙 ;孙国胜 ;苏蓉 ;孙珍军 |
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| 作者单位： | 1. 吉林大学 地球科学学院，长春 130061; 2. 防灾科技学院 地震科学系，北京 101601 |
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| 基金项目： | 国家自然科学基金项目（41172039）. |
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| 摘 要： | 通过LA-ICP-MS锆石U-Pb测年对内蒙古敖汉旗克力代岩体进行研究。结果表明,岩浆锆石的加权平均年龄为263±1 Ma,表明其结晶年龄为中二叠世。岩石地球化学分析表明,岩体具有高Si(SiO2=69.94%～72.56%),富ALK(Na2O+K2O=8.04%～9.23%),贫Fe(FeOT=1.50%～1.82%)、Mg(MgO=0.65%～0.86%)、Ti(TiO2=0.32%～0.35%)的特点;A/CNK值为0.87～0.93,为准铝质;A/NKC1.1,显示出I型花岗岩特征。固结指数(SI)为6.06～7.36,分异指数(DI)为88.82～91.82,说明岩体经历了较强的分异演化作用。稀土元素总量较低(ΣREE=91.76×10-6～143.16×10-6),轻稀土明显富集,重稀土相对亏损,LREE/HREE值平均为9.14,(La/Yb)N平均值为8.36,δEu平均值为0.58,为Eu亏损型。大离子亲石元素(LILE)Rb、K较富集,强烈亏损高场强元素(HFSE)Nb、Ti、Ta。因此,判定克力代岩体为高钾钙碱性I型花岗岩。结合测年结果和地球化学特征,判定该岩体为晚海西期华北板块和西伯利亚板块碰撞作用形成的同碰撞型花岗岩。
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| 关 键 词： | 克力代岩体 锆石 U--Pb 年代学 地球化学 中二叠世 内蒙古 |
Zircon U-Pb dating and geochemistry of Kelidai pluton in Aohanqi,Inner Mongolia |
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| LUO Long,SUN Guo-Shing,SU Rong,SUN Zhen-Jun.Zircon U-Pb dating and geochemistry of Kelidai pluton in Aohanqi,Inner Mongolia[J].World Geology,2014,33(2):299-310. |
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| Authors: | LUO Long SUN Guo-Shing SU Rong SUN Zhen-Jun |
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| Institution: | 1. College of Earth Sciences，Jilin University，Changchun 130061，China; 2. Department of Earthquake Science，Institute of Disaster Prevention，Beijing 101601，China |
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| Abstract: | LA-ICP-MS zircon U-Pb dating indicated that the ages of zircons from Kelidai pluton are （263 ±1） Ma,related to Middle Permian.The rocks are characterized by high Si （SiO2 =69.94％ ～ 72.56％）,high alkali （Na2O ＋ K2O =8.04％ ～ 9.23％）,low iron,magnesium and titanium （FeOT =1.50％ ～ 1.82％,MgO =0.65％ ～0.86％,TiO2=0.32％ ～0.35％）.A/CNK value was 0.87 ～0.93,A/NKC ＜ 1.1,belonging to quasi -aluminous Ⅰ-type granites.The rocks experienced a highly fractionated and evolving stage reflected from DI （88.82 ～ 91.82） and SI （6.06 ～ 7.36）.The rocks have low abundance of REE （∑REE =91.76 × 10-6 ～ 143.16 × 10-6）,with variable differentiation between LREE and HREE （LREE/HREE average as 9.14 and （La/ Yb） N average as 8.36）,revealling LREE enrichment and HREE depletionand with negative Eu anomalies （average δEu =0.58）,and enrichment in LILE （Rb,K） but depleted in HFSE （Nb,Ti,Ta）.In combination with the discrimination diagram,the Kelidai pluton belonged to high-potassium calc-alkaline Ⅰ-type granites.Considered the chronology results and geochemical characteristics,the rocks were syn-collisional granites formed in the collision between North China and Siberia plates in Late Hercynian. |
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| Keywords: | Kelidai pluton zircon U-Pb geochronology geochemistry Middle Permian Inner Mongolia |
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