| 东秦岭商丹地区富铷花岗伟晶岩脉矿化特征及其地质意义 |
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| 引用本文： | 朱伟鹏,宋公社,许锋,杨文博,吴鹏.东秦岭商丹地区富铷花岗伟晶岩脉矿化特征及其地质意义[J].地质科技通报,2022,41(3):54-67. |
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| 作者姓名： | 朱伟鹏 宋公社 许锋 杨文博 吴鹏 |
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| 基金项目： | 陕西省公益性地质矿产调查专项[2012]56陕西省地质调查院公益性地质矿产科研类专项20170304 |
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| 摘 要： | 花岗伟晶岩作为稀有金属矿产的重要来源，其矿化特征有待深入探讨。采用野外地质调查，室内镜下鉴定以及主量、微量和稀土元素含量分析相结合的方法，系统研究了东秦岭商丹地区资峪沟富铷花岗伟晶岩脉的岩石学和地球化学特征。结果显示:资峪沟花岗伟晶岩脉主要集中产出于丹凤岩群中，经综合评价后圈定出14条出露的富铷脉体，依据石榴石含量和岩石蚀变类型可将其划分为微斜长石花岗伟晶岩、富石榴石微斜长石花岗伟晶岩、云英岩化微斜长石花岗伟晶岩、云英岩化富石榴石微斜长石花岗伟晶岩与硅化微斜长石花岗伟晶岩5种类型；资峪沟花岗伟晶岩脉总体显示为过铝质，富集Rb、高场强元素(HFSE)和重稀土元素(HREE)，亏损Ba, Sr和Ti，其中少含或不含石榴石且未发生蚀变的花岗伟晶岩脉通常具有较高的Rb含量，因此，可以将原生微斜长石、石榴石及次生白云母、石英作为标型矿物来综合判断花岗伟晶岩脉的铷矿化程度；资峪沟花岗伟晶岩脉的形成时代明显晚于宽坪花岗岩体，二者的地球化学特征存在显著差异，经综合分析得出花岗伟晶岩脉并非由宽坪花岗岩体的岩浆演化而来，其母岩可能位于宽坪花岗岩体下方的更深部位。
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| 关 键 词： | 东秦岭 商丹地区 富铷花岗伟晶岩脉 矿化特征 地质意义 |
| 收稿时间： | 2021-08-05 |
Mineralization characteristics and geological significance of Rb-rich granitic pegmatite veins in Shangnan-Danfeng area,eastern Qinling belt |
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| Abstract: | Granitic pegmatite is an important source of rare metal minerals, but its mineralization characteristics need to be further studied. This study conducted a combined field geological, indoor microscopic and major-trace elemental investigation on the petrological and geochemical characteristics of the Ziyugou Rb-rich granitic pegmatite veins in the Shangnan-Danfeng area of the eastern Qinling belt. The Ziyugou granitic pegmatites intruded the Danfeng Group. After comprehensive evaluation, 14 Rb-rich granitic pegmatite veins have been identified. On the basis of garnet contents and alteration types, the granitic pegmatites can be divided into five types: microcline granitic pegmatite, garnet-rich microcline granitic pegmatite, greisenized microcline granitic pegmatite, greisenized garnet-rich microcline granitic pegmatite and silicified microcline granitic pegmatite. The Ziyugou granitic pegmatite veins are generally peraluminous, rich in Rb, HFSE and HREE but depleted in Ba, Sr and Ti. Granitic pegmatite veins with little or without alteration usually contain highest Rb contents. Therefore, primary microcline, garnet, secondary muscovite and quartz can be served as key minerals to effectively indicate the Rb fertility of granitic pegmatite veins. The Ziyugou granitic pegmatite veins obviously postdate the Kuanping granite, and both of them exhibit significantly different geochemical characteristics. These features strongly indicate that the Ziyugou granitic pegmatite veins cannot be derived from the magmas forming the Kuanping granite, and their parent rocks were speculated to be located in depth. |
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