| 孔令添,黎敦朋,张森琦,罗坤.青海共和盆地东部曲乃亥花岗闪长岩锆石U-Pb定年及地球化学特征[J].地质找矿论丛,2019,34(3):423-431 |
| 青海共和盆地东部曲乃亥花岗闪长岩锆石U-Pb定年及地球化学特征 |
| Zircon U-Pb dating and geochemical characteristics of the Qunaihai granodiorite in the eastern part of the Gonghe Basin, Qinghai province |
| 投稿时间：2019-04-19 |
| DOI：10.6053/j.issn.1001-1412.2019.03.012 |
| 中文关键词: 曲乃亥花岗闪长岩 锆石U-Pb定年 岩石地球化学 构造环境 青海省 |
| 英文关键词:Qunaihai granodiorite zircon U-Pb dating lithogeochemistry tectonic environment Qinghai province |
| 基金项目:中国地质调查局"青海西宁-贵南地区地热资源调查"项目（编号：DD20179621）资助。 |
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| 中文摘要: |
| 文章对青海共和盆地东部曲乃亥花岗闪长岩体的岩石学、岩石地球化学、年代进行了研究，其结果表明：曲乃亥花岗闪长岩LA-ICP-MS锆石U-Pb定年239.4 Ma±2.8 Ma（n=16，MSWD=0.29），表示该岩体形成于中三叠世；岩石的主量元素地球化学特征值反映曲乃亥花岗闪长岩（体）具富硅、富钾、准铝质-过铝质等特征，属于高钾钙碱性花岗岩；岩石的微量元素地球化学分析显示，富集大离子亲石元素（如Rb、Th、K、U），亏损高场强元素（如Nb、Ta、Ti），在稀土配分图上呈现轻稀土元素富集、重稀土元素亏损的右倾曲线特征；岩石构造环境判别图解反映曲乃亥花岗闪长岩（体）为Ⅰ型花岗岩，属于俯冲环境下活动大陆边缘构造作用所形成的产物，其可能主要来自于地壳物质的部分熔融。 |
| 英文摘要: |
| This paper studied petrology, chronology and rock geochemistry of Qunaihai granodiorite in the eastern part of the Gonghe Basin. The LA-ICP-MS zircon U-Pb dating of the granodiorite is 239.4 Ma±2.8 Ma (n=16, MSWD=0.29) indicating that the rock mass was formed in the Middle Triassic Epoch. Major elements of the granodiorite are characteristic of silicon-rich, potassium-rich, metaluminous to weak peraluminous material thus it belongs to high-potassium-calcium-alkaline granite; trace elements characteristic of enrichment of large-ionic lithophile elements (Rb, Th, K, U) and depletion of high-field strength elements (Nb, Ta, Ti) LREE enrichment and HREE depletion pattern. In the geotectonic environment discremination plot it is identified as I-type granite, the product of active continental marginal structural activity under subduction environment derived mainly from partial melting of the crustal material. |
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