| 辽宁兴城新立屯地区岩浆杂岩岩石学特征、侵位顺序及地质意义 |
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| 引用本文： | 周晓萍,郑常青,徐学纯,刘云虎,钟定鼎,张慧明,崔一兵.辽宁兴城新立屯地区岩浆杂岩岩石学特征、侵位顺序及地质意义[J].世界地质,2015,34(3):571-589. |
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| 作者姓名： | 周晓萍 郑常青 徐学纯 刘云虎 钟定鼎 张慧明 崔一兵 |
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| 作者单位： | 吉林大学 地球科学学院，长春 130061 |
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| 摘 要： | 辽宁兴城新立屯地区岩浆杂岩主要由4种不同的岩石单元组成,分别为似斑状黑云母二长花岗岩,中细粒石英闪长岩,花岗细晶岩和花岗伟晶岩,前两者分布广泛且为研究区的主要岩石单元,后两者则呈脉状侵入到前两者中。应用LA-ICP-MS锆石U-Pb定年方法,测得似斑状黑云母二长花岗岩,中细粒石英闪长岩及花岗细晶岩的年龄分别为2 496±18 Ma,2 490±19 Ma,2 479±29 Ma,形成于古元古代早期。结合野外地质特征,侵位顺序由早到晚依次为:似斑状黑云母二长花岗岩,中细粒石英闪长岩,花岗细晶岩,花岗伟晶岩。岩石地球化学特征显示,新立屯地区岩浆杂岩主量元素方面具高硅(SiO2=61.38%~74.99%),富碱(Na2O+K2O=6.86%~9.41%),富Mg#(56~70)特征;A/CNK=0.91~1.18,属准铝质-过铝质岩石;微量元素方面,相对富集轻稀土元素,亏损重稀土元素,具有Eu异常(δEu=0.50~0.96);富集大离子亲石元素,亏损高场强元素;锆石Lu-Hf同位素特征εHf(t)值为-1.12~+6.13;TDM2(Hf)介于2 594~2 937 Ma,显示该套岩浆杂岩可能为地幔物质加入新生地壳再造的产物。
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| 关 键 词： | 辽宁 兴城 新立屯地区 岩浆杂岩 LA- - ICP- - MS 锆石 U- - Pb 定年 古元古代早期 侵位顺序 |
Petrology,emplacement sequence and geological significance of magmatic complex in Xinlitun of Xingcheng,Liaoning |
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| ZHOU Xiao-Ping,ZHENG Chang-Qing,XU Xue-Chun,LIU Yun-Hu,ZHONG Ding-Ding,ZHANG Hui-Ming,CUI Yi-Bing.Petrology,emplacement sequence and geological significance of magmatic complex in Xinlitun of Xingcheng,Liaoning[J].World Geology,2015,34(3):571-589. |
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| Authors: | ZHOU Xiao-Ping ZHENG Chang-Qing XU Xue-Chun LIU Yun-Hu ZHONG Ding-Ding ZHANG Hui-Ming CUI Yi-Bing |
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| Institution: | College of Earth Sciences，Jilin University，Changchun 130061，China |
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| Abstract: | Magmatic complex in Xinlitun of Liaoning is mainly composed of four different kinds of rocks，in- cluding biotite monzogranite，medium- fine quartz diorite，granite aplite and granite pegmatite． The later two pres- ented as fine veins intruding into the former two which are the main rock units and widely distributed． LA- - ICP- - MS zircons U - - Pb dating yielded three concordant ages of 2 496 ±18 Ma for biotite monzogranite，2 490 ±19 Ma for medium- fine quartz diorite and 2 479 ±29 Ma for granite aplite， indicating the instrusive time is Early Paleoprotero- zoic． Combined with their contact relationships in the field，the authors infer that biotite monzogranite intruded firstly，then medium- fine quartz diorite，granite aplite in turn and granite pegmatite at last． The major elements show that magmatic complex in Xinlitun has high Si (SiO 2 =61. 38% ～74. 99%) ，high Alkali (Na 2 O + K 2 O = 6. 86% ～9. 41%) ，high Mg # (56 ～70) and A/CNK ratios range from 0. 91 to 1. 18，and it belongs to metalu- minous- peralumous rock． Besides，the ＲEE patterns are characterized by the enrichment of LＲEEs，depletion of HＲEEs and distinct negative Eu anomalies (δEu = 0. 50 ～ 0. 96) in chondrite － normalized ＲEE diagram． The rocks are also enriched in large lithophile elements (LILE)，depleted in high field strength elements (HFSE)． Combined with the results of zircon Lu- - Hf isotope (ε Hf (t) = －1. 12 ～ ﹢6. 13，T DM2 (Hf) =2 594 ～2 937 Ma)， we can draw the conclusion that magmatic complex is the product of mantle material，which are contaminated by ju- venile crust． |
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| Keywords: | Liaoning Xingcheng Xinlitun area magmatic complex LA- -ICP- -MS zircons U- -Pb dating Early Paleoproterozoic emplacement sequence |
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