| 腾冲地块高地热异常区晚白垩世-始新世钾玄质强过铝花岗岩岩石地球化学、年代学特征及构造意义 |
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| 引用本文： | 林木森,彭松柏,乔卫涛,李辉.腾冲地块高地热异常区晚白垩世-始新世钾玄质强过铝花岗岩岩石地球化学、年代学特征及构造意义[J].岩石学报,2014,30(2):527-546. |
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| 作者姓名： | 林木森 彭松柏 乔卫涛 李辉 |
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| 作者单位： | 中国地质大学地球科学学院, 武汉 430074;中国地质大学地球科学学院, 武汉 430074;中国地质大学教育部长江三峡库区地质灾害研究中心, 武汉 430074;中国地质大学地球科学学院, 武汉 430074;贵州省地质调查院, 贵阳 550004;中国地质大学地球科学学院, 武汉 430074 |
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| 基金项目： | 本文受国土资源部深部探测技术与实验研究专项课题（201011060）资助. |
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| 摘 要： | 腾冲地块高地热异常区清水左所营初糜棱岩化黑云母二长花岗岩岩体、新华黑石河热田强糜棱岩化黑云母二长花岗岩岩体、热海热田硫磺塘硅化碎裂正长花岗岩岩体变形变质、岩石地球化学及锆石年代学的研究表明,晚白垩世(73Ma)初糜棱岩化黑云母二长花岗岩岩体为高温钾玄质强过铝花岗岩,形成于活动大陆边缘火山弧-后碰撞转换或过渡构造环境,并经历强烈伸展变形作用,普遍发育早期近水平-低角度(30°)韧性伸展剪切糜棱面理,局部发育晚期高角度右旋走滑挤压韧性糜棱面理;始新世(48~46Ma)强糜棱岩化黑云母二长花岗岩岩体、硅化碎裂正长花岗岩岩体为中-高温钾玄质强过铝花岗岩,并具铝质A型花岗岩特征,形成于后碰撞-板内构造环境,以发育晚期高角度(70°~87°)右旋走滑挤压韧性糜棱面理为特征,其右旋走滑韧性剪切变形时代晚于始新世(48~46Ma)。晚白垩世-始新世钾玄质强过铝花岗岩的形成与俯冲-碰撞造山隆升后的伸展垮塌、拆沉地幔物质上涌玄武质岩浆底侵和地壳部分熔融作用密切相关。始新世-第四纪岩浆活动与高地热异常区(带)空间上密切伴生,新近纪晚期-第四纪构造活动主要表现为脆性走滑-拉张正断层和构造拉分断陷盆地的形成,构造断陷边界断裂与深部岩浆活动是导致腾冲地区高地热异常区(带)中-高温地热温泉沿走滑-拉张断裂带集中分布的主要原因。
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| 关 键 词： | 钾玄质强过铝花岗岩 变形变质 岩石地球化学 LA-ICP-MS U-Pb定年 构造意义 高地热异常区 腾冲地块 |
| 收稿时间： | 2013/1/27 0:00:00 |
| 修稿时间： | 2013/4/28 0:00:00 |
Petro-geochemistry and geochronology of late Cretaceous-Eocene granites in high geothermal anomaly areas in the Tengchong block, Yunnan Province, China and their tectonic implications. |
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| LIN MuSen,PENG SongBai,QIAO WeiTao and LI Hui.Petro-geochemistry and geochronology of late Cretaceous-Eocene granites in high geothermal anomaly areas in the Tengchong block, Yunnan Province, China and their tectonic implications.[J].Acta Petrologica Sinica,2014,30(2):527-546. |
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| Authors: | LIN MuSen PENG SongBai QIAO WeiTao and LI Hui |
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| Institution: | Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China;Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China;Three Gorges Research Center for Geo-hazards, Ministry of Education, China University of Geosciences, Wuhan 430074, China;Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China;Guizhou Academy of Geological Survey, Guiyang 550004, China;Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China |
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| Abstract: | Within the high geothermal anomaly areas in the Tengchong block, proto-mylonitic biotite monzonitic granite, ultramylonitized biotite monzonitic granite and silicified fractured syenogranite, are exposed in Zuosuoying of Qingshui, Heishihe of Xinhua, and Liuhuangtang of Rehai, respectively. Studies of deformation, metamorphism, petro-geochemistry and geochronology suggest that Late Cretaceous (73Ma) proto-mylonitic biotite monzonitic granite is a high temperature shoshonitic and strongly peraluminous granite formed in an active continental margin volcanic arc to a post-collisional tectonic setting. This granite has an early nearly horizontal (<30°) stretching shear mylonitic foliation, with locally developed later high-angle dextral strike-slip extrusion mylonitic foliation. Eocene (48~46Ma) ultra-mylonitized biotite monzonitic granite and silicified fractured syenogranite are medium-high temperature shoshonitic and strongly peraluminous A-type granites, which formed in a post-collisional environment to a within plate tectonic setting, where late high-angle (70°~87°) dextral strike-slip shear mylonitic foliations were developed. Late Cretaceous-Eocene shoshonitic and strongly peraluminous granitic magmatism was associated with basaltic magma underplating and partial melting of the crust, generated by upwelling mantle, which resulted from extensional collapse and delamination following the subduction-collision orogenic uplift. Eocene-Quaternary magma activity was spatially associated with high geothermal anomaly areas. The tectonic evolution during Late Neocene to Quaternary is represented by the formation of the strike-slip faults and extensional normal faults associated with extensional fault basin. Accordingly, the boundary faults of fault basins as well as deep magmatism are the predominant reasons for the concentrated distribution of the medium-high temperature geothermal springs along the strike-slip extensional fault zones. |
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| Keywords: | Shoshonitic strongly peraluminous granites Deformation and metamorphism Petro-geochemistry LA-ICP-MS U-Pb dating Tectonic implications High geothermal anomaly areas Tengchong block |
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