| 大兴安岭南段道伦达坝黑云母花岗岩成岩时代、锆石微量元素、Lu-Hf同位素特征及地质意义 |
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| 引用本文： | 李岩,许立权,李廷栋,肖庆辉,郭灵俊,程杨,范玉须,庞进力,袁伟明,罗鹏跃.大兴安岭南段道伦达坝黑云母花岗岩成岩时代、锆石微量元素、Lu-Hf同位素特征及地质意义[J].地球科学,2020,45(7):2585-2597. |
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| 作者姓名： | 李岩 许立权 李廷栋 肖庆辉 郭灵俊 程杨 范玉须 庞进力 袁伟明 罗鹏跃 |
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| 作者单位： | 1.内蒙古自治区岩浆活动成矿与找矿重点实验室, 内蒙古呼和浩特 010020 |
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| 基金项目： | 内蒙古自治区地质矿产勘查基金项目2017-YS01 |
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| 摘 要： | 道伦达坝铜多金属矿床位于大兴安岭成矿带南段，对道伦达坝矿床黑云母花岗岩开展了锆石U-Pb测年、锆石微量元素和Lu-Hf同位素研究.锆石U-Pb LA-ICP-MS测年结果显示黑云母花岗岩形成时代为282.2±4.5~287.0±3.7 Ma.锆石Lu-Hf同位素研究结果显示黑云母花岗岩锆石均具有较高的176Hf/177Hf（平均值分别为0.282 770和0.282 769）和低的176Lu/177Hf（平均值分别为0.002 224和0.001 984）同位素组成，εHf（t）值变化范围为3.05~8.58之间和2.31~7.36，二阶段模式年龄分别为730.22~1 083.46 Ma和812.42~1 134.56 Ma，暗示其来源为年轻的新生下地壳，可能遭受了古老地壳的混染.锆石微量元素研究显示，黑云母花岗岩的锆石具有低的Nb含量（< 2×10-6）和强烈的Eu异常，符合S型花岗岩特征.锆石的Ti饱和温度平均值为770℃和785℃，指示其源区经历了水近饱和情况下的部分熔融，暗示其可能形成于俯冲环境下.
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| 关 键 词： | 道伦达坝Cu多金属矿 早二叠世 锆石U-Pb定年 锆石微量元素 Lu-Hf同位素 兴蒙造山带 地球化学 |
| 收稿时间： | 2020-04-29 |
Geochronology,Zircon Trace Element and Lu-Hf Isotope Characteristics of the Biotite Granite and Their Geological Significance from Daolundaba Cu Polymetallic Deposit,Southern Great Hinggan Ling,China |
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| Abstract: | Daolundaba Cu polymetallic deposit islocated in southern segment of Great Hinggan Ling metallogenic belt. In this study, we carried out chronological studies of LA-ICP-MS zircon U-Pb ages, zircon trace element and Lu-Hf isotope for the biotite granites in Daolundaba deposit. LA-ICP-MS zircon U-Pb dating results suggested that the formation age of the biotite granites range from 282.2±4.5-287.0±3.7 Ma.Lu-Hf isotope analysis of the biotite granite showed that the biotite granites had high isotopic compositions of 176Hf/177Hf (mean values of 0.282 770 and 0.282 769) and low isotopic compositions of 176Lu/177Hf (mean values of 0.002 224 and 0.001 984), εHf(t) values range from 3.05-8.58 and 2.31-7.36, with older two-stage ages (730.22-1 083.46 Ma and 812.42-1 134.56 Ma). Zircon trace element results suggest eda S-type granites characteristic with al ow Nb(< 2×10-6)values and large negative Euanomalies. The forming mean temperatures of the biotite granite calculated by zircon Tithermometer are 770℃ and 785℃, indicated that its magmas is like lytorelate to a subducted environment, and the source region probably experienced partial melting with water nearly saturation. The Daolundaba copper polymetallic deposit was formed in the Late Permian subduction environment. |
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