| 东秦岭陡岭杂岩花岗岩的Sr—Nd—Pb同位素特征及其地质意义 |
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| 引用本文： | 杨斌虎,张成立,李雷.东秦岭陡岭杂岩花岗岩的Sr—Nd—Pb同位素特征及其地质意义[J].中国区域地质,2011(2):439-447. |
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| 作者姓名： | 杨斌虎 张成立 李雷 |
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| 作者单位： | 大陆动力学国家重点实验室／西北大学地质系,陕西西安710069 |
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| 基金项目： | 科技部“973”重点基础研究计划项目《深俯冲地壳的化学变化与差异折返》（编号：2009CB825003）和大陆动力学国家重点实验室科技部专项《中国中西部大陆深俯冲作用及其地球动力学》 致谢：论文写作过程与西北大学地质系刘良教授进行了有益的讨论,西北大学大陆动力学国家重点实验室刘烨、王建其以及宗春蕾老师完成了主微量及同位素元素分析,在此一并致谢. |
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| 摘 要： | 东秦岭陡岭杂岩中甘沟、三坪沟和封子山等花岗岩体SiO2含量变化大，低碱、高钠，富集LREE和LILE，贫HFSE，亏损Nb、Sr、P和Ti，具准铝质钙碱性Ⅰ型花岗岩的特征。吐雾山岩体富Si、碱，高Al，贫Ca、Mg，稀土元素总量高，Eu负异常强，富集Rb、Th、U和Pb，明显亏损Sr、P和Ti，显示了A2型花岗岩的地球化学特征。2类花岗岩体Nd-Pb同位素组成基本一致，指示源自相同的物质源区，地球化学特征的差异主要为岩浆分异演化途径不同所致。它们的Pb同位素组成明显不同于北秦岭基底岩系及同时代花岗岩的高放射性成因Pb，与南秦岭和扬子地块基底岩系低放射成因Pb同位素组成类似，表明这次花岗岩浆活动是新元古代中期扬子地块统一陆块形成过程中岩浆活动在秦岭地区的反映，与北秦岭构造带无任何成因联系。
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| 关 键 词： | 花岗岩 Sr—Nd—Pb同位素 陡岭杂岩 东秦岭 |
Sr-Nd-Pb isotopic characteristics of the granitoids in the Douling complexes, eastern Qinling, China and its geological significance. |
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| YANG Bin-hu,ZHANG Cheng-li,LI Lei.Sr-Nd-Pb isotopic characteristics of the granitoids in the Douling complexes, eastern Qinling, China and its geological significance.[J].Regional Geology of China,2011(2):439-447. |
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| Authors: | YANG Bin-hu ZHANG Cheng-li LI Lei |
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| Institution: | (State Key Laboratory of Continental Dynamics/Department of Geology, Northwest University, Xi＇an 710069, Shaanxi, China) |
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| Abstract: | The granitic batholiths in Douling complexes of eastern Qinling, such as Gangou, Sanpinggou and Fengzishan intrusions, are characterized by large variation of SiO2, low alkaline, high Na2O and enriched in LREE and LILE as well as poor in HFSE and depleted in Nb, Sr, P and Ti, displaying peraluminous calc-alkaline Ⅰ-type granitoids. In contrast, Tuwushan intrusion, as a small granitic body, is highly enriched in SiO2 and alkaline, with higher total REE and strong negative Eu anomaly as well as enrichment in t/b, Th, U and Pb and strong depletes in St, P and Ti, showing geochemical features of A2-type granite. Both of them have similar Nd-Pb isotopic composition, indicating that they were formed by partial melting from the same crustal materials. Whereas, the difference of geochemical characteristics between them was resulted from quite different processes during magma evolution. In addition, they have low radiogenic Pb isotopic composition similar to those of basement blocks in southern Qinfing and Yangtze block but quite different to those of basement and granitoids in northern Qinling with the higher radiogenic Pb isotopic composition, suggesting that the granitic magmatism in southern Qinling should be closely related to the final formation of Yangtze block during mid-Neoproterozoic, lack of any genesis relationship with northern Qinling. |
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| Keywords: | granitoids Sr-Nd-Pb isotopes Douling complexes eastern Qinling |
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