| 延边地区古洞河韧性剪切带变形特征及变形时代 |
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| 引用本文： | 张超,刘永江,张照录,崔芳华,张超,关庆彬,李烨.延边地区古洞河韧性剪切带变形特征及变形时代[J].地球科学,2019,44(10):3252-3264. |
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| 作者姓名： | 张超 刘永江 张照录 崔芳华 张超 关庆彬 李烨 |
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| 作者单位： | 1.山东理工大学资源与环境工程学院, 山东淄博 255049 |
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| 基金项目： | 中国地质调查局项目DD20190042-03山东省重大科技创新工程深部金矿资源评价理论、方法与预测项目2017CXGC1604国家自然科学青年基金项目41802238国土资源部东北亚矿产资源评价重点实验室开放课题基金项目DBY-KF-18-11山东省中青年科学家科研奖励基金项目ZR2016DB08 |
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| 摘 要： | 古洞河韧性剪切带位于兴蒙造山带东段南缘，其变形特征和时间对探讨延边地区晚古生代-中生代构造演化具有重要意义.鉴于此，对该韧性剪切带进行了锆石U-Pb年代学和显微构造解析，以期限定韧性剪切带变形时间和特征.研究结果显示，古洞河韧性剪切带具有多期变形的特征，晚期变形糜棱叶理倾向为西，倾角较缓，线理倾伏向为南西，具有由南西向北东方向右行逆冲的特征.其分形维数值为1.159~1.214，Flinn参数K值为0.19~0.31，Kruhl温度计显示变形温度为450~550℃，石英动力重结晶粒径估算的差应力值为16.83~20.09 MPa，古应变速率为10-12~10-14 s-1.古洞河韧性剪切带花岗质糜棱岩锆石U-Pb年龄为192±2 Ma，晚期变形时代应为早侏罗世，形成应与早侏罗世古太平洋板块向欧亚大陆俯冲有关.
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| 关 键 词： | 古洞河韧性剪切带 分形维数 显微构造 延边地区 古太平洋构造域 构造学 |
| 收稿时间： | 2019-04-18 |
Deformation and Geochronological Characteristics of Gudonghe Ductile Shear Zone in Yanbian Area |
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| Abstract: | The Gudonghe ductile shear zone, located in southern section of eastern Xing-Meng orogenic belt, is a key to understanding the Late Paleozoic-Early Mesozoic tectonic evolution in Yanbian area. In this paper, zircon U-Pb dating and microstructure analysis were done for constraining the deformation time and features of Gudonghe ductile shear zone. The results show that Gudonghe ductile shear zone represents a multi-phase suite of mylonites with dextral shear thrust characteristics and W gneissosity and SW lineation. Systematic measurement of finite strains of Quartz in later mylonites indicates that the K value is 0.19 to 0.31. And Kruhl thermometer shows that the deformation temperatures of ductile shear zone range from 450 to 550℃. Fractal analysis shows that the numbers of fractal dimension vary from 1.159 to 1.214. The paleo-stress values from dynamically recrystallized grain sizes of quartz are 16.83 to 20.09 MPa, while estimated strain rates are on the order of 10-12 to 10-14 s-1. The zircon U-Pb dating of granitic mylonite is 192±2 Ma, indicating that the deformation time of Gudonghe ductile shear zone is not earlier than Early Jurassic and the deformation features show the ductile shear zone thrust from southwest to northeast. However, the tectonic setting of Gudonghe ductile shear zone is mostly related to the subduction of paleo-Pacific beneath the Eurasian continent. |
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