| 姚兴华,张志平,梁硕鹏,刘彩英,张晓娟.西藏山南努日地区比马组火山岩地球化学特征及成因[J].矿产勘查,2019,(9):2119-2128 |
| 西藏山南努日地区比马组火山岩地球化学特征及成因 |
| Geochemistry and origin of the volcanic rocks in Bima Formation,in Nuri area, Shannan, Tibet |
| 投稿时间：2019-05-22 |
| DOI： |
| 中文关键词: 努日 比马组 地球化学 俯冲消减 岛弧 |
| 英文关键词: Nuri, Bima Formation, geochemistry, subduction, island arc |
| 基金项目:中国地质调查局项目(编号:121201010000150014-46、DD20160015-08)资助。 |
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| 中文摘要: |
| 桑日群火山岩带是拉萨地块南缘火山—岩浆弧中一条非常重要的火山岩带,被认为是新特提斯洋壳沿拉萨地块南缘北向俯冲消减作用的产物, 是俯冲作用的代表性岩浆记录,对了解新特提斯洋的演化历史以及拉萨地块的构造演化具有重要的意义。资料显示,位于桑日群上部的比马组在走向上岩石组合不尽相同。本文选取山南努日地区比马组中酸性火山岩为研究对象,研究显示,努日地区比马组火山岩为高SiO2、Al2O3,低TiO2、MgO、Yb,富集大离子亲石元素和轻稀土元素,亏损中稀土元素及高场强元素Nb、Ti、Ce、P的一套钙碱性火山岩系列,地球化学特征及Sr-Nd同位素显示该套火山岩是晚白垩世新特提斯洋向北俯冲、消减过程中地壳岩石发生部分熔融形成,其形成构造环境为活动大陆边缘陆侧的岛弧环境。 |
| 英文摘要: |
| Sangri Group volcanic rocks are generally thought to be typical products of the Neo-Tethys northward subduction along the south margin of the Gangdese arc belt,record the subduction of representative magmatic.It is of great significance to understanding the evolutionary history of Neo-Tethys and the Lhasa block tectonic evolution. The research data reveal Bima Formation has different rock association in alignment. The research show that the volcanic rock belongs to calc-alcaline series, has high SiO2,Al2O3,low TiO2,MgO,Yb,enrich in LILE and LREE,depleted MREE and HFSE(Nb,Ti,Ce,P),in Nuri area, Shannan. Geochemical characterist and Sr-Nd isotope indicate that the rocks of Bima Formation resulted from partial melting of the upper part of oceanic crust during Neo-Tethys northward subduction, and the tectonic setting is the island arc on the continental margin of active continental margin. |
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