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| 藏南定结地区早中新世淡色花岗岩的形成机制及其构造动力学意义 | |
| 引用本文： | 于俊杰,曾令森,刘静,高利娥,谢克家.藏南定结地区早中新世淡色花岗岩的形成机制及其构造动力学意义[J].岩石学报,2011,27(7):1961-1972. |
| 作者姓名： | 于俊杰 曾令森 刘静 高利娥 谢克家 |
| 作者单位： | 1. 中国科学院青藏高原研究所大陆碰撞与高原隆升重点实验室,北京100085;中国科学院研究生院,北京100049 2. 中国地质科学院地质研究所大陆构造与动力学国家重点实验室,北京,100037 3. 中国科学院青藏高原研究所大陆碰撞与高原隆升重点实验室,北京,100085 |
| 基金项目： | 本文受科技部973 项目(2011CB403102)、国家自然科学基金(41073024、40921001)、中国地质科学院地质所所长基金(J1004)和中国地质调查局项目(1212010918030)联合资助. |
| 摘 要： | 定结日玛那穹窿位于高喜马拉雅带中段,由花岗片麻岩、变泥质岩、变基性岩及大量淡色花岗岩等组成,经历了角闪岩-麻粒岩相变质作用。为厘定淡色花岗岩的形成机制以及与高级变质岩的关系,我们对淡色花岗岩和高级变质岩进行了全岩元素和Sr和Nd同位素组成和SHRIMP锆石U-Pb地质年代学测试。全岩元素和Sr-Nd同位素测试结果揭示淡色花岗岩具有以下特征:(1)高SiO2 (>72%),高Al2O3 (>12%)和高A/CNK比值 (>1.0);(2)高Rb,低Sr,高Rb/Sr比值(>1.0);(3)高∑REE和明显的负Eu异常;(4)高Sr同位素初始比值(0.7621~0.8846)和低εNd(t)值(-13.0~-20.2)。淡色花岗岩的高Rb/Sr比值和Sr-Nd同位素系统特征表明其形成机制为主要为白云母脱水部分熔融作用,源区为由花岗片麻岩和变泥质岩组成的混合源区。SHRIMP锆石U-Pb年代学研究揭示出定结地区淡色花岗岩具有21.0±0.7Ma和15.8±0.1Ma 2期年龄,花岗片麻岩的锆石变质增生边年龄为22.2±1.4Ma,与该区的榴辉岩退变质年龄一致。这些数据共同表明,花岗片麻岩和 变泥质岩在22~21Ma发生高级变质和深熔作用,形成早期淡色花岗岩岩浆,在~16Ma进一步深熔,形成晚期淡色花岗岩岩浆。 |
| 关 键 词： | 淡色花岗岩 花岗片麻岩 变泥质岩 高喜马拉雅 地壳深熔作用 |
| 收稿时间： | 2/1/2011 12:00:00 AM |
| 修稿时间： | 5/1/2011 12:00:00 AM |
Early Miocene leucogranites in Dinggye area, southern Tibet: Formation mechanism and tectonic implications |
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| YU JunJie,ZENG LingSen,LIU Jing,GAO LiE and XIE KeJia.Early Miocene leucogranites in Dinggye area, southern Tibet: Formation mechanism and tectonic implications[J].Acta Petrologica Sinica,2011,27(7):1961-1972. | |
| Authors: | YU JunJie ZENG LingSen LIU Jing GAO LiE and XIE KeJia |
| Institution: | Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China;Graduate University of Chinese Academy of Sciences, Beijing 100049, China;State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China;State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China |
| Abstract: | The Ama Drime Massif, Dinggye area, is located in the central Greater Himalaya and consists of granitic gneisses, metapelites, metabasites and massive leucogranites, and has experienced amphibolite- to granulite-facies metamorphism. Whole-rock major- and trace-element, radiogenic isotope (Sr and Nd), and SHRIMP zircon analyses were undertaken to investigate the petrogenic relationship between the leucogranites and the metamorphic rocks, as well as the formation mechanism of the leucogranites. Bulk element a... |
| Keywords: | Leucogranite Granitic gneiss Metpelite Greater Himalaya Crustal anatexis |
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