藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩同位素地球化学研究被引量：4

STUDY ON ISOTOPIC GEOCHEMISTRY OF CENOZOIC HIGH-K CALC-ALKALINE VOLCANIC ROCKS IN THE ZUERKENGWULA MOUNTAIN AREA, NORTHERN TIBET

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摘要　通过对藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩Sr,Nd,Pb同位素成分的系统测试分析表明,火山岩具有相对高的87Sr/86Sr和低的143Nd/144Nd值及高的Pb同位素组成特点,且Sr,Nd,Pb同位素比值变化范围很窄,反映了其具有同源岩浆的特点,并且经历了类似的地球化学动力学过程。Sr,Nd,Pb同位素组成及相关图解判别表明,藏北祖尔肯乌拉山地区新生代高钾钙碱岩系火山岩来源于被大洋沉积物和地壳物质所混合的不均一富集地幔源区,显示源区具有壳幔混源性质,与EM 型富集地幔源特征一致。 The characteristics of radiogenic Sr, Pb and unradiogenic Nd show that the Cenozoic high-K calc-alkaline series volcanic rocks from Zuerkengwula mountain area in Northern Tibetan Plateau have a relatively high value of ^(87)Sr/^(86)Sr, a relatively low value of ^(143)Nd/^(144)Nd and a relatively high Pb isotopic composition.Sr, Nd and Pb isotopic composition also vary at a small range,indicating that Cenozoic high-K calc-alkaline series volcanic rocks in the region have the same magma source with a similar geochemistry-dynamils. The characteristics of isotopic geochemistry infer that Cenozoic high-K calc-alkaline series volcanic rocks were from the partial melting of the inhomogeneonsly enriched EMⅡ mantle, in which the crustal material and oceanic sediments were largely involved.

作者林金辉伊海生时志强赵兵李葆华黄继钧

机构地区成都理工大学

出处《矿物岩石》 CAS CSCD 北大核心 2004年第4期59-64,共6页 Mineralogy and Petrology

基金国家重点基础研究发展计划项目"青藏高原形成演化及其环境资源效应"(编号1998040801-5) 青海乌兰乌拉湖幅1:25×104区域地质调查(编号200013000147)

关键词 PB同位素火山岩新生代藏北同位素地球化学富集地幔源区山地 EM 组成特点 isotopic geochemistry high-K calc-alkaline series volcanic rocks Cenozoic period enriched EMⅡ mantle Northern Tibet

分类号 P588 [天文地球—岩石学] P597.2 [天文地球—地球化学]

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