| 西藏驱龙矿区早侏罗世斑岩的Sr-Nd-Pb及锆石Hf同位素研究 |
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| 引用本文： | 杨志明,侯增谦,江迎飞,张洪瑞,宋玉财.西藏驱龙矿区早侏罗世斑岩的Sr-Nd-Pb及锆石Hf同位素研究[J].岩石学报,2011,27(7):2003-2010. |
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| 作者姓名： | 杨志明 侯增谦 江迎飞 张洪瑞 宋玉财 |
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| 作者单位： | 中国地质科学院地质研究所,北京,100037 |
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| 基金项目： | 本文受国家基础研究规划(973)项目(2011CB403104)、公益性行业科研专项(201011011)和地质大调查项目(1212011121253)联合资助. |
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| 摘 要： | 近年的研究基本揭示,在冈底斯南缘存在一条晚三叠世-侏罗纪的花岗岩带,其成因认识有助于恢复青藏高原中生代演化历史,但却存在争议。为此,本文选择拉萨东部驱龙早侏罗世花岗斑岩开展Sr-Nd-Pb及锆石Hf同位素研究,调查岩浆源区特征,以期查明岩浆成因。分析结果显示,驱龙早侏罗世斑岩具有相对较低的87Sr/86Sr初始比值(0.7029~0.7050)、正的εNd(t)(平均0.7)和锆石εHf(t)值(2.6~8.2),表明岩浆来自新生地壳物质的部分熔融。综合对比发现,冈底斯南部晚三叠世-早侏罗世花岗岩的锆石Hf同位素在500km宽的范围内显示出由西向东亏损程度逐渐减弱、甚至变得富集的规律,表明在此类花岗岩的形成过程中,成熟地壳组分的贡献自西向东逐渐增多。这既可因南部拉萨地体基底Hf同位素组成的东西向不均一所引起,也可能因东段驱龙、米林等地花岗岩更靠近古老的拉萨微陆块所致。
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| 关 键 词： | Sr-Nd-Pb-Hf同位素 侏罗纪花岗岩 区域对比 冈底斯 西藏 |
| 收稿时间： | 4/1/2011 12:00:00 AM |
| 修稿时间： | 2011/5/28 0:00:00 |
Sr-Nd-Pb and zircon Hf isotopic constraints on petrogenesis of the Late Jurassic granitic porphyry at Qulong, Tibet |
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| YANG ZhiMing,HOU ZengQian,JIANG YingFei,ZHANG HongRui and SONG YuCai.Sr-Nd-Pb and zircon Hf isotopic constraints on petrogenesis of the Late Jurassic granitic porphyry at Qulong, Tibet[J].Acta Petrologica Sinica,2011,27(7):2003-2010. |
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| Authors: | YANG ZhiMing HOU ZengQian JIANG YingFei ZHANG HongRui and SONG YuCai |
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| Institution: | Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China |
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| Abstract: | Recent investigations indicate there is a Late Triassic-Early Jurassic granite belt in the southern margin of the Lhasa terrane. Their petrogenesis is important to understand Mesozoic evolution history of Tibet plateau, but has not been well constrained by far. In the study, we report Sr-Nd-Pb and zircon Hf isotopic compositions of the Late Jurassic granitic porphyries at Qulong, Tibet. The results show that the granitic porphyries have relatively low initial 87Sr/86Sr values (0.7029~0.7050), slightly negat... |
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| Keywords: | Sr-Nd-Pb-Hf isotope Jurassic granite Regional comparison Gangdese Tibet |
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