| 吉东大栗子铁矿区石英二长斑岩U-Pb年龄、地球化学及Hf同位素组成 |
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| 引用本文： | 叶丽娜,孙丰月,王力,刘金龙,张宇婷.吉东大栗子铁矿区石英二长斑岩U-Pb年龄、地球化学及Hf同位素组成[J].地球科学,2020,45(5):1544-1555. |
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| 作者姓名： | 叶丽娜 孙丰月 王力 刘金龙 张宇婷 |
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| 作者单位： | 1.吉林大学地球科学学院, 吉林长春 130061 |
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| 基金项目： | 科技部深地专项2017YFC0601304国家重点研发项目2017YFC0601304 |
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| 摘 要： | 吉林东部地区侏罗纪花岗岩的分布较为有限，缺乏区域构造演化环境的判别证据.对侵入到老岭群当中的隐伏岩体石英二长斑岩进行了U-Pb年代学、地球化学和Hf同位素研究.获得石英二长斑岩样品锆石LA-ICP-MS U-Pb定年结果165±1Ma，属中侏罗世；岩石SiO2=61.01%~61.99%，全碱含量（K2O+Na2O）为5.78%~7.98%，属钙碱性系列岩石，贫MgO、CaO、Fe2O3T，A/CNK=1.02~1.39，轻稀土元素富集明显，Eu/Eu*=0.92~1.01，异常不明显，显示I型花岗岩特征；岩石εHf（t）值为-15.46~-17.04，二阶段模式年龄TDM2=2 189~2 290 Ma，富集大离子亲石元素，亏损高场强元素，Mg#=26.90~33.04，贫Yb（0.43×10-6~0.48×10-6）和Y（6.63×10-6~7.12×10-6），锆石Ti温度均值为744℃，属低温花岗岩.岩浆源区为古元古代下地壳的部分熔融.华北克拉通北缘东段中侏罗世火成岩形成于俯冲背景之下，而非蒙古-鄂霍茨克洋闭合的远程效应，至晚侏罗世-早白垩世早期，中国东北陆缘可能进入走滑的构造属性.
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| 关 键 词： | 石英二长斑岩 锆石U-Pb定年 Hf同位素 地球化学 |
| 收稿时间： | 2019-07-24 |
Zircon U-Pb Geochronology,Geochemistry and Hf Isotopic Composition of the Quartz Monzonite Porphyry Intrusion from East Jilin Province |
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| Abstract: | The distribution of Jurassic granite in the eastern Jilin province is relatively limited, with little discriminant evidence for regional tectonic evolution. This paper presents a synthesis study of zircon U-Pb chronology and geochemistry and Hf isotopes of the quartz monzonite porphyry in this area. The rocks yield an average zircon LA-ICP-MS U-Pb age of 165±1 Ma, indicating the Middle Jurassic. They show high SiO2(61.01%-61.99%), ALK(5.78%-7.98%), belonging to calc-alkaline granites. In addition, they also display the characteristics of I-type granite with obvious enrichment in LREE, unconspicuous europium anomalies (0.92-1.01), low MgO, CaO, Fe2O3Tas well as A/CNK(1.02-1.39). The Eu/Eu* values vary from -15.46 to -17.04, and TDM2=2 189-2 289 Ma. These samples are enriched in LILE and depleted in HFSE, with Mg#=26.90-33.04, low Yb(0.43×10-6~0.48×10-6) and Y(6.63×10-6~7.12×10-6). Zircon Ti temperature averages 744 ℃, belonging to low temperature granite. The magma was originated from the partial melting of Paleo-Proterozoic lower crust. The middle Jurassic igneous rocks in the eastpartofnorthern margin of the North China Craton were formed in the subduction rather than the remote effect of Mongols-Okhotsk Ocean closure. From late Jurassic to early Cretaceous, the continental margin of northeast China maydisplay the structural features of strike-slip. |
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