| 东准噶尔木炭窑地区同造山花岗岩锆石U-Pb定年、地球化学及地质意义 |
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| 引用本文： | 张征峰,熊双才,范香莲.东准噶尔木炭窑地区同造山花岗岩锆石U-Pb定年、地球化学及地质意义[J].地质论评,2021,67(1):231-241. |
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| 作者姓名： | 张征峰 熊双才 范香莲 |
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| 作者单位： | 新疆地矿局第一地质大队，新疆昌吉，831100 |
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| 基金项目： | 本文为中央返还新疆两权价款“新疆巴里坤县1∶5万L46E020016、L46E020017、L46E021015、L46E021016、L46E022015、L46E022016六幅区域地质调查”(编号: T15- 1- LQ02)的成果 |
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| 摘 要： | 木炭窑地区位于东准噶尔东部。木炭窑同造山花岗岩具有高硅、富碱、贫钙、低钛的特征,富集大离子亲石元素Rb、Ba、K、Th及高场强元素Zr,相对亏损P、Ti、Nb、Ta。稀土元素总量较低,轻稀土富集明显,且轻稀土元素内部分馏相对较强,重稀土元素元素内部分馏较弱,弱的Eu负异常(δEu=0.64~0.95)。锆石温度饱和温度740~807℃;在Sr—Yb图中投入浙闽型与Adakitic型(高锶低钇型或译埃达克型)花岗岩之间,属中高等压力。综合岩石学和地球化学特征,认为其成因类型为Ⅰ型花岗岩,成岩物质主要来源地壳砂岩和少量泥质岩部分熔融,并且有少量地幔物质参与。LA-ICP-MS锆石U-Pb年龄显示其结晶年龄为349.8±3.5 Ma,表明其形成时代为早石炭世。综合本文数据及区域地质特征,木炭窑地区在早石炭世早期进入俯冲向碰撞造山转化的过渡期,拼贴到西伯利亚板块,开始了地壳的侧向和垂向增生。
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| 关 键 词： | 东准噶尔 Ⅰ型花岗岩 同造山 锆石U-PB定年 岩石地球化学 早石炭世 |
| 收稿时间： | 2019/9/24 0:00:00 |
| 修稿时间： | 2020/10/9 0:00:00 |
Zircon U- Pb dating, geochemistry and geological significance of synorogenic- granit in Mutanyao area, eastern Junggar |
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| ZHANG Zhengfeng,XIONG Shuangcai,FAN Xianglian.Zircon U- Pb dating, geochemistry and geological significance of synorogenic- granit in Mutanyao area, eastern Junggar[J].Geological Review,2021,67(1):231-241. |
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| Authors: | ZHANG Zhengfeng XIONG Shuangcai FAN Xianglian |
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| Institution: | No. 1 Geological Party, Xinjiang Bureau of Geology and Mineral Resources, Changji, Xinjiang, 831100 |
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| Abstract: | Objectives:Mutanyao area is located in east of East Junggar,known as the important tectonic metallogenic belt of the Central Asian Orogenic Belt(CAOB).Through high-precision zircon U-Pb dating and comprehensive research on rock geochemistry,combined with regional comparison,the diagenetic age was determined and its formation environment was discussed to provide chronology and petro-geochemical constraints for the study of Late Paleozoic tectonic magmatism.Methods:The full analysis of the rock was tested in the Aussie Minerals Laboratory in Guangzhou.After the sample was crushed,shrunk and ground to 200 mesh,the content of rare earth elements was determined by ME MS81 fusion inductively coupled plasma mass spectrometry.ME XRF26X fluorescence spectrometer was used for precise analysis.Determination of iron oxide by the main trace element of rock and Fe VOL05 titration.Zircon single minerals were selected in the laboratory of the Institute of Regional Geology and Mineral Resources Research of Hebei Province,and the target,CL photographing,transflective photography,zircon dating and data were carried out in the State Key Laboratory of Mineral Deposits Research Mechanism of Endogenous Metal Deposits,Nanjing University.Correction.The zircon U-Pb test was carried out on an Agilient 7500 a ICP-MS connected by a193 nm laser sampling system.The laser ablation beam spot diameter was 32μm and the frequency was 6 Hz.He gas was used as the carrier gas for the ablation material,and then mixed with the Ar gas.Analyze.The isotope ratios obtained by the experiment were processed by the GLITTER program and subjected to ordinary lead calibration.The test results are shown in Table 2.The age harmonic curve and the weighted average calculation were processed using Isoplot(3.0)software.Results:Mutanyao syn-orogenic granites are characterized by high SiO2,high alkaline,low CaO and low TiO2.Concentration of large ion lithophile element Rb,Ba,K,Th and high field strength element Zr,are relatively deficient in P,Ti,NB,Ta.The total amount of rare earth elements is relatively low,the concentration of light rare earth elements is obvious,and the internal fractionation of light rare earth elements is relatively strong,the internal fractionation of heavy rare earth elements is weak,and the weak negative Eu anomaly(δEu=0.64~0.95).The saturation temperature of zircon is 740~807℃.It belongs to medium—high pressure when it is put between Zhejiang—Fujian type and Adak type granite in Sr—Yb diagram.Based on petrology and geochemistry,it is considered that the genetic type of granite isⅠtransition type.The diagenetic material mainly comes from partial melting of crustal sandstone and a small amount of argillaceous rock,and a small amount of mantle material is involved.The U-Pb age of LA-ICP-MS zircon shows that its crystallization age is 349.8±3.5 Ma,indicating that it was formed in the Early Carboniferous.Conclusions:The Mutanyao area entered the transition period from subduction to collision orogeny in the early Early Carboniferous(349.8±3.5 Ma),collaged to the Siberian plate,and began the lateral and vertical crustal accretion. |
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| Keywords: | east Junggar Ⅰ-type granite petrochemisty syn-orogeny zircon U-Pb dating Early Carboniferous |
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