| 西藏西南部达巴-休古嘎布蛇绿岩带中地幔橄榄岩的成因 |
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| 引用本文： | 徐德明,黄圭成,黄陵勤,雷义均,李丽娟.西藏西南部达巴-休古嘎布蛇绿岩带中地幔橄榄岩的成因[J].华南地质与矿产,2006(3):10-18. |
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| 作者姓名： | 徐德明 黄圭成 黄陵勤 雷义均 李丽娟 |
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| 作者单位： | 1. 宜昌地质矿产研究所,湖北,宜昌,443003
2. 湖南省地质矿产勘查局四一六队,湖南,株州,412003 |
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| 基金项目： | 中国地质调查局资助项目 |
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| 摘 要： | 本文报道了西藏西南部达巴-休古嘎布蛇绿岩带中橄榄岩的矿物化学资料.橄榄岩中主要造岩矿物化学成分的分析研究表明,该区橄榄岩为残余地幔成因,但它们不是地幔简单熔化的残余物.尖晶石中Cr#及辉石中Ti的广泛变化表明它们具有复杂的熔融历史及地幔交代作用的印记,其形成过程可能经历了两种构造环境的转变.早期在MORB环境下形成低Cr#(尖晶石)橄榄岩;其后由于洋内俯冲作用,早先形成的低熔橄榄岩被消减到岛弧之下再度发生熔融形成高Cr#(尖晶石)橄榄岩.从而,在古大洋消失之后形成的碰撞带上同时保存了MORB型和SSZ型两类蛇绿岩.
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| 关 键 词： | 地幔橄榄岩 矿物化学 地幔熔融 地幔交代 达巴-休古嘎布蛇绿岩带 |
| 文章编号： | 1007-3701（2006）03-0010-09 |
| 收稿时间： | 2005-04-26 |
| 修稿时间： | 2005年4月26日 |
The Origin of Mantle Peridotites in the Daba-Xiugugabu Ophiolite Belt,SW Tibet |
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| XU De-ming,HUANG Gui-cheng,HUANG Lin-qin,LEI Yi-jun,LI Li-juan.The Origin of Mantle Peridotites in the Daba-Xiugugabu Ophiolite Belt,SW Tibet[J].Geology and Mineral Resources of South China,2006(3):10-18. |
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| Authors: | XU De-ming HUANG Gui-cheng HUANG Lin-qin LEI Yi-jun LI Li-juan |
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| Abstract: | This paper reports the mineral chemical data of mantle peridotites in the Daba-Xiugugabu ophiolite Belt, SW Tibet. In the relationship between Cr^# of spinel and Fo of olivine, the peridotites fall within the OSMA and it indicate they are the residual mantle peridotite, but not residue of a simple partial melting. The variations of Cr^# in spinel and Ti in pyroxene suggest that the Daba-Xiugugabu peridotite had a history of complex melting and an impress of mantle metasomatism. The processes of formation of the peridorites possibly include a transition from a tectonic setting to another. The lower Cr^# of spinel in peridotite can be explained by partial melting and MORB extraction in mid-ocean stage. Subsequently, the peridotites with low melting degree were subducted beneath the arc area and re-melted, and peridotites with higher Cr^# of spinel formed. Therefore, two of MORB-type and SSZ-type ophiolite crop out along collision belt formed after the closing of the old ocean. |
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| Keywords: | mantle peridotites mineral chemistry mantle melting mantle metasomatism Daba-Xiugugabu ophiolite belt |
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