| 中亚造山带东缘迪彦庙俯冲增生杂岩带早二叠世洋内弧岩浆作用及构造背景 |
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| 引用本文： | 程杨,肖庆辉,李廷栋,郭灵俊,李岩,范玉须,庞进力.中亚造山带东缘迪彦庙俯冲增生杂岩带早二叠世洋内弧岩浆作用及构造背景[J].地球科学,2019,44(10):3454-3468. |
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| 作者姓名： | 程杨 肖庆辉 李廷栋 郭灵俊 李岩 范玉须 庞进力 |
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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2017-YS01 |
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| 摘 要： | 洋陆转换岩石学证据（洋内弧）的发现使识别、重建、研究洋盆转化为大陆成为可能.对中亚造山带东缘迪彦庙俯冲增生杂岩带内蛇绿岩开展岩石地球化学、Sr-Nd同位素以及锆石U-Pb年代学研究，识别出一套洋内弧火成岩组合.MORB-Like玄武岩锆石U-Pb谐和年龄为286.1±6.1 Ma，代表洋内初始俯冲时代；HMA锆石U-Pb谐和年龄为283.7±4.7 Ma，代表首次岩浆作用后、俯冲程度加深的岩浆作用时代；岛弧拉斑玄武岩（IAT）锆石U-Pb谐和年龄为241±5 Ma，指示古亚洲洋早三叠世逐渐向着正常岛弧岩浆作用转换的大陆化方向发展.从MORB-Like玄武岩到HMA再到IAT的岩石组合序列代表了洋内俯冲作用由浅到深的递进演变以及洋盆向大陆边缘岛弧逐步演化的洋陆转换过程.
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| 关 键 词： | 洋内弧 初始俯冲 洋陆转换 地球化学 Sr-Nd同位素 锆石U-Pb年代学 中亚造山带 |
| 收稿时间： | 2019-04-18 |
Magmatism and Tectonic Background of Early Permian Intra-Oceanic Arc in Diyanmiao Subduction Accretion Complex Belt in Eastern Margin of Central Asian Orogenic Belt |
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| Abstract: | The discovery of petrological evidence for the ocean-continent conversion (intra-oceanic arc) makes it possible to identify, reconstruct and study the ocean-continent conversion. In this paper, the ophiolite in the Diyanmiao subduction accretion complex belt in the eastern margin of the Central Asian orogenic belt was studied in terms of petrogeochemistry, Sr-Nd isotope and zircon U-Pb geochronology, and a set of igneous assemblages in the intra-oceanic arc were identified. The zircon U-Pb concordant age of MORB-like basalt is 286.1±6.1 Ma, representing the period of initial subduction in the ocean. The zircon U-Pb concordant age of HMA is 283.7±4.7 Ma, which represents the age of magmatism when subduction deepened after the first magmatic action. The zircon U-Pb concordant age of IAT is 241±5 Ma, indicating that the paleo-Asian Ocean developed towards continental transition of normal island arc magmatism in the Early Triassic. The sequence of rock assemblages from MORB-like to HMA to IAT represents the progressive evolution of intra-oceanic subduction from shallow to deep and the gradual evolution of ocean basin to the island arc of the continental marginal. |
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