| 新疆东天山泥盆纪火山岩岩石学特征及其形成的大地构造环境 |
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| 引用本文： | 肖渊甫,茅燕石.新疆东天山泥盆纪火山岩岩石学特征及其形成的大地构造环境[J].矿物岩石,1992,12(2):34-42. |
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| 作者姓名： | 肖渊甫 茅燕石 |
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| 作者单位： | 成都地质学院，成都地质学院，成都地质学院 成都 610059，成都 610059，成都 610059 |
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| 摘 要： | 新疆东天山地区泥盆纪火山活动频繁,火山岩广泛发育。火山岩系由钙碱系列(占75％)石英安山岩、英安岩、玄武岩、碱长流纹岩以及大量的火山碎屑岩,和拉斑玄武系列(约占25％)的石英拉斑玄武岩,少量橄榄拉斑玄武岩组成。岩石普遍富含Na_2O,SiO_2,而贫MgO,K_2O,以CaO,属钠质型和普通型。稀有元素配分型式具“三隆起”特征,过渡族元素呈明显的“W”形态,稀土元素为铕平坦或略具亏损的轻稀土富集型。据研究,火山岩由南至北具明显的钾元素地球化学极性。反映其板块构造环境为一俯冲带倾向北的陆壳型岛弧。
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| 关 键 词： | 泥盆纪 火山岩 岩石学 大地构造 |
THE PETROLOGIC CHARACTERISTICS OF VOLCANIC ROCKS IN DEVONIAN AND THE TECTONICS ENVIRONMENT IN EASTERN TIANSHAN,XINJIANG |
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| Xiao Yuanfu Mao Yanshi Zhou Jiyuan.THE PETROLOGIC CHARACTERISTICS OF VOLCANIC ROCKS IN DEVONIAN AND THE TECTONICS ENVIRONMENT IN EASTERN TIANSHAN,XINJIANG[J].Journal of Mineralogy and Petrology,1992,12(2):34-42. |
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| Authors: | Xiao Yuanfu Mao Yanshi Zhou Jiyuan |
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| Abstract: | The volcanism during Devonian was intensive in eastern Tianshan,Xinjiang,and the volcanic rocks are widely dispersed over this area. Volcanic rock series is composed of the calc-alkaline series (75%)including quartz-andesite,dacite,basalt,alkal-feldspar-rhyolite and a large number of volcanoclastic rocks,and tholeiitic series (about 25%)including quartz-tholeiite and a small amount olivinetholeiite. The volcanic rocks are rich in Na_2O,SiO_2,and poor in MgO,K_2O,CaO,it is of sodium type and general type. The panitioning patterns of trace elements have the character of "three ridges". The partitioning patterns of transitional elements are obviously the form of "W",and REE is rich in LREE in which Eu is of the smooth or a slight depletion type.
According to our study, the geochemcal polarity of K element in volcanic rocks is more obvious from south to north. It reflects that the plate tectonics environment is a type of crustal island arc and the Benioff zone trends northward. |
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| Keywords: | Eastern Tianshan calc-alkaline series tholeiltic series geochemical polarity island arc |
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