| 北祁连山元古宙末－寒武纪主动大陆裂谷火山作用 |
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| 引用本文： | 夏祖春,夏林圻,徐学义.北祁连山元古宙末－寒武纪主动大陆裂谷火山作用[J].地球学报,1996,17(3):282-291. |
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| 作者姓名： | 夏祖春 夏林圻 徐学义 |
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| 作者单位： | 中国地质科学院西安地质矿产研究所;中国地质科学院西安地质矿产研究所;中国地质科学院西安地质矿产研究所 |
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| 摘 要： | 北祁连山元古宙末－寒武纪大陆裂谷火山岩系为双峰式火山岩套，主要由基性与酸性火山岩组成。基性火山岩有磁性玄武岩与拉斑玄武岩两个岩浆系列，且富集ＬＲＥＥ与ＬＩＬ，其岩浆源区为与洋岛玄武岩源相似的富集地幔柱源。软流圈地幔柱上涌导致岩石圈地慢部分熔融，其熔体与地幔柱衍生熔浆混合，形成本区具有中等钕，锶同位素比值特点的基性岩浆。基性岩浆上侵至陆壳，引起下部陆壳深熔，产生长英质岩浆。地幔柱上隆促使大陆扩张，及至形成北祁连山元古宙末－寒武纪大陆裂谷。
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| 关 键 词： | 元古宙末－寒武纪 主动大陆裂谷 火山岩 北祁连山 |
The Late-Proterozoic-Cambrian Active Continental Rift Volcanism in Northern Qilian Mountains |
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| XIA Zu-chun,XIA Lin-qi and XU Xue-yi.The Late-Proterozoic-Cambrian Active Continental Rift Volcanism in Northern Qilian Mountains[J].Acta Geoscientia Sinica,1996,17(3):282-291. |
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| Authors: | XIA Zu-chun XIA Lin-qi and XU Xue-yi |
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| Abstract: | The Late- Proterozoic- Cambrian continental rift volcanic rock series display a bimodal suite, which consist of basic and acidic volcanic rocks. The basic rocks, which belong to alkali and tholeiitic magma series, enriched in LREE and LIL. The magmatic source of basic volcanic rocks was enrichment mantle being analogous to oceanic island basalts sources. The asthenospheric plume ascended and impacted with the lithosphere and led the lithospheric mantle partial melting. The plume-derived melts mixed the lithospheric mantle-derived melts and formed the primary basic magma, which characterized by middle ENd values and middle (87Sr/86Sr), values. The basic magma ascened into continental crust and induced anatexis of the crust which produced felsic magma. The mantle plume upwelling may promote the continental extention, then the Late-Proterozoic-Cambrian continental rift in Northern Qilian mountains was formed. |
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| Keywords: | Late-Proterozoic-Cambrian active contmental rift volcanic rocks northern Qilian mountains |
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