| Island-arc geochemical signatures of Cenozoic alkali-rich intrusive rocks from western Yunnan and their implication |
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| 作者姓名： | WU Kaixing |
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| 作者单位： | [1]Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China [2]Graduate School of the Chinese Academy of Sciences, Beijing 100039, China [3]Chinese Zhongmei Energy Source Corporation Lid, Beijing 100011, China |
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| 基金项目： | 中国科学院资助项目，中国科学院资助项目 |
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| 摘 要： | Alkali-rich intrusive rocks in western Yunnan were derived from an enriched lithospheric mantle （ EM Ⅱ ） source. The data available indicated they are alkali-rich （ K2o ＋ Na2o 〉 8wt% ） and shoshonitic. Although formed in a within-plate environment they exhibit signatures of arc magmatic rocks, such as high amounts of LILE and LREE relative to the HFSE and HREE, and thus high Ba/Nb, Ba/Zr, Sr/Y, La/Yb ratios as well as mimic chondrite-normalized REE and primitive mantle-normalized trace element patterns of subducted sediments, and they fall in the collision- or arc-related tectonic setting field on all discrimination diagrams. This might suggest the enrichment be related to the substantial extent of sediment contamination by the Mesozoic Tethyan subduction processes.
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| 关 键 词： | 云南 碱性岩 金沙江 地球化学 |
Island-arc geochemical signatures of Cenozoic alkali-rich intrusive rocks from western Yunnan and their implication |
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| Kaixing Wu,Ruizhong Hu,Xianwu Bi,Jiantang Peng,Xinzhi Zhan,Long Chen.Island-arc geochemical signatures of Cenozoic alkali-rich intrusive rocks from western Yunnan and their implication[J].Chinese Journal of Geochemistry,2005,24(4):361-369. |
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| Authors: | Kaixing Wu Ruizhong Hu Xianwu Bi Jiantang Peng Xinzhi Zhan Long Chen |
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| Institution: | (1) Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550002 Guiyang, China;(2) Graduate School of the Chinese Academy of Sciences, 100039 Beijing, China;(3) Chinese Zhongmei Energy Source Corporation Ltd, 100011 Beijing, China |
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| Abstract: | Alkali-rich intrusive rocks in western Yunnan were derived from an enriched lithospheric mantle (EMⅡ) source. The data available indicated they are alkali-rich (K2O Na2O>8wt%) and shoshonitic. Although formed in a within-plate environment they exhibit signatures of arc magmatic rocks, such as high amounts of LILE and LREE relative to the HFSE and HREE, and thus high Ba/Nb, Ba/Zr, Sr/Y, La/Yb ratios as well as mimic chondrite-normalized REE and primitive mantle-normalized trace element patterns of subducted sediments, and they fall in the collision- or arc-related tectonic setting field on all discrimination diagrams. This might suggest the enrichment be related to the substantial extent of sediment contamination by the Mesozoic Tethyan subduction processes. |
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| Keywords: | alkali-rich intrusive rock western Yunnan shoshonitic arc geochemical affinities enrichment |
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