| 川西甲基卡二云母花岗岩与伟晶岩脉地球化学特征及其地质意义 |
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| 引用本文： | 李名则,秦宇龙,李峥,徐云峰,武文辉,刘伟,叶亚康,周雄.川西甲基卡二云母花岗岩与伟晶岩脉地球化学特征及其地质意义[J].岩石矿物学杂志,2018,37(3):366-378. |
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| 作者姓名： | 李名则 秦宇龙 李峥 徐云峰 武文辉 刘伟 叶亚康 周雄 |
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| 作者单位： | 稀有稀土战略资源评价与利用四川省重点实验室;四川省地质调查院;四川省地质矿产勘查开发局113地质队;中国地质调查局成都矿产综合利用研究所 |
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| 基金项目： | 中国地质调查局地质调查项目（DD20160074）；四川省科技厅重点研发项目（2018SZ0276）；中国地质调查局地质调查子项目（121201004000150017-93，12120113049500） |
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| 摘 要： | 对川西甲基卡地区二云母花岗岩及伟晶岩脉的岩石学特征、地球化学特征进行了分析,探讨了二云母花岗岩物质来源、构造背景及其与伟晶岩脉的成因联系。分析结果表明,甲基卡二云母花岗岩的SiO_2含量在73.93%~75.06%之间;全碱含量7.90%~8.36%,钾质含量较高,属高钾钙碱性系列岩石;Al_2O_3含量为14.24%~14.77%,A/CNK=1.14~1.24,具强过铝质S型花岗岩特征;ΣREE=31.18×10~(-6)~41.67×10~(-6),LREE/HREE=4.15~6.41,δEu=0.46~0.70;CaO/Na_2O=0.07~0.12(0.3),指示其物源可能是含砂屑物质极少的泥质岩;Al_2O_3/TiO_2=133.1~279.8,比值较高,表明甲基卡二云母花岗岩属高压低温型后碰撞强过铝质岩石。花岗伟晶岩脉SiO_2含量在72.59%~80.91%之间,全碱含量5.26%~10.60%,Al_2O_3含量11.79%~17.64%,σ=0.74~3.80,A/CNK=0.98~2.38,ΣREE=4.03×10~(-6)~8.29×10~(-6),LREE/HREE=2.61~10.40,δEu=0.18~0.68,与岩体差异明显,主、微量元素含量变化也较大。甲基卡二云母花岗岩与伟晶岩脉有密切的成因联系。岩浆不混溶作用可能是形成甲基卡含矿伟晶岩脉的关键因素,花岗质岩浆在上升过程中通过不混溶作用分离出富含挥发分的伟晶岩熔体,在运移或侵位过程中可能交代围岩矿物而使稀有金属元素进一步富集。二云母花岗岩浆和伟晶岩熔体性质的不同导致稀土元素和Th、Sr、Ti、Y、Rb、N等微量元素在两者中含量有明显差异。伟晶岩熔体在运移或就位过程中所经的路径不同和周围环境的差异导致不同位置产出的伟晶岩的元素含量有较大的变化。与二云母花岗岩相比,花岗伟晶岩的形成演化具有一定的跳跃性。
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| 关 键 词： | 川西甲基卡 二云母花岗岩 伟晶岩脉 强过铝质 后碰撞 高压低温型 岩浆不混溶作用 |
| 收稿时间： | 2017/5/23 0:00:00 |
Geochemical characteristics of two-mica granite and granite pegmatite in Jiajika area, western Sichuan, and their geological implications |
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| LI Ming-ze,QIN Yu-long,LI Zheng,XU Yun-feng,WU Wen-hui,LIU Wei,YE Ya-kang and ZHOU Xiong.Geochemical characteristics of two-mica granite and granite pegmatite in Jiajika area, western Sichuan, and their geological implications[J].Acta Petrologica Et Mineralogica,2018,37(3):366-378. |
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| Authors: | LI Ming-ze QIN Yu-long LI Zheng XU Yun-feng WU Wen-hui LIU Wei YE Ya-kang and ZHOU Xiong |
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| Institution: | Key Laboratory of Sichuan Province for Strategic Resources Evaluation and Utilization of Rare Metals and Rare Earth, Chengdu 610081, China;Sichuan Geological Survey, Chengdu 610081, China,Key Laboratory of Sichuan Province for Strategic Resources Evaluation and Utilization of Rare Metals and Rare Earth, Chengdu 610081, China;Sichuan Geological Survey, Chengdu 610081, China,Key Laboratory of Sichuan Province for Strategic Resources Evaluation and Utilization of Rare Metals and Rare Earth, Chengdu 610081, China;Sichuan Geological Survey, Chengdu 610081, China,Key Laboratory of Sichuan Province for Strategic Resources Evaluation and Utilization of Rare Metals and Rare Earth, Chengdu 610081, China;Sichuan Geological Survey, Chengdu 610081, China,Key Laboratory of Sichuan Province for Strategic Resources Evaluation and Utilization of Rare Metals and Rare Earth, Chengdu 610081, China;Sichuan Geological Survey, Chengdu 610081, China,No. 113 Geological Party of Sichuan Bureau of Geology and Mineral Resources, Luzhou 646000, China,Chengdu Institute of Multiple Utilization of Mineral Resources, China Geological Survey, Chengdu 610041, China and Chengdu Institute of Multiple Utilization of Mineral Resources, China Geological Survey, Chengdu 610041, China |
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| Abstract: | |
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| Keywords: | Jiajika two-mica granite pegmatile strongly peraluminous post-collision high-pressure-low-temperature magma immiscibility |
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