| 滇西腾冲新生代火山岩岩石地球化学特征 |
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| 引用本文： | 徐翠玲,赵广涛,何雨旸,李德平.滇西腾冲新生代火山岩岩石地球化学特征[J].海洋地质与第四纪地质,2012(2):65-75. |
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| 作者姓名： | 徐翠玲 赵广涛 何雨旸 李德平 |
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| 作者单位： | 中国海洋大学海洋地球科学学院;中国海洋大学海底科学与探测技术教育部重点实验室 |
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| 摘 要： | 腾冲新生代火山岩位于印度板块和欧亚板块碰撞带附近,但是喷发时大洋已经闭合,属于大陆板内火山岩。对其进行地球化学研究,可以用来划分构造属性和推测岩浆来源。采用XRF和ICP-MS对典型岩石样品进行了较系统的岩石地球化学研究,结果表明,岩石类型有玄武质粗面安山岩、粗面安山岩和玄武安山岩,属高钾钙碱性系列;岩石化学显示高K2O、CaO和低TiO2,Mg#较高,平均约为46;稀土元素分布呈右倾,显示明显的Eu负异常;相对于原始地幔富集大离子亲石元素和高场强元素,并具有明显的Th正异常;地球化学组成总体上与岛弧岩浆岩相似,推测其成因与印度板块向欧亚板块俯冲引发的岩浆活动有关。特征元素比值显示岩浆可能来源于与俯冲作用相关的EMⅠ型地幔。
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| 关 键 词： | 地球化学 岛弧 火山岩 新生代 腾冲 |
GEOCHEMISTRY OF CENOZOIC VOLCANIC ROCKS FROM TENGCHONG,WESTERN YUNNAN |
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| XU Cuiling,ZHAO Guangtao,HE Yuyang,LI Deping.GEOCHEMISTRY OF CENOZOIC VOLCANIC ROCKS FROM TENGCHONG,WESTERN YUNNAN[J].Marine Geology & Quaternary Geology,2012(2):65-75. |
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| Authors: | XU Cuiling ZHAO Guangtao HE Yuyang LI Deping |
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| Institution: | 1(1 College of Marine Geosciences,Ocean University of China,Qingdao 266100,China; 2 Key Laboratory Of Submarine Geosciences and Prospecting Techniques,Ministry of Education, Ocean University of China,Qingdao 266100,China) |
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| Abstract: | Tengchong Cenozoic volcanic rocks,which consist of basaltic trachy-andesite,trachy-andesite,and basaltic andesite,belonging to the high-K and calc-alkaline series,are continental intraplate volcanic rocks erupted after the Tethys Ocean was closed.They are distributed near the collision zone of the Indian plate and the Eurasian plate.The geochemical features of the rocks can be used to define the tectonic properties and magma sources.The systematic geochemical study of the typical rock samples by XRF and ICP-MS shows that the rocks are characterized by high K2O,CaO,low TiO2,and high Mg #(averaging about 46).REE shows a LREE-enriched pattern with significantly negative Eu.Large ion lithophile elements(LILE) and high field strength elements(HFSE) are enriched compared to the primitive mantle,and the LILE have higher enrichment than the HFSE.Th shows a significantly positive anomaly.The geochemical composition of the studied volcanic rocks is similar to the volcanic arc magma,suggesting that the magmatic activity was triggered by the subduction of the Indian plate down to the Eurasian plate.Characteristic element ratios show that the magma may be derived from the subduction-related EMⅠmantle. |
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| Keywords: | geochemistry island arc volcanic rocks Cenozoic Era Tengchong |
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