| 内蒙古额济纳旗灰石山稀土铌多金属矿床地质特征及成因 |
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| 作者姓名： | 陈海东 王占富 鲁宁 张海峰 谢建玺 |
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| 作者单位： | 内蒙古地质矿产勘查院,呼和浩特 010010 |
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| 摘 要： | 灰石山稀土铌多金属矿床位于内蒙古阿拉善地块北缘,是近些年新发现的规模较大的稀土铌多金属矿床。通过系统的槽探钻探工程、野外地质调查及岩相学研究,探讨了该稀土铌多金属矿床的地质特征及成因。灰石山稀土铌多金属矿床与碱性正长岩密切相关,具岩浆期后热液交代型和岩浆结晶分异型2种不同成因类型。通过总结该矿床的找矿标志,建立了成矿模式: 岩浆期后热液交代型矿床受断裂控制,正长质岩浆沿断裂被动侵位,随着温度和压力的下降,流体与熔体发生溶离作用,富含Nb、REE和挥发分(F和Cl为主)的硅质流体发生水-岩反应,在有利部位形成了稀土铌矿床。矿床围岩褐铁矿化、黄铁矿化、硅化蚀变程度与稀土、铌的含量呈正相关,矿体与围岩界线不明显; 正长质岩浆主动侵位,伴随岩浆结晶分异作用,不相容元素(Nb、REE等)在残余熔体中富集成矿,形成了赋存于正长岩中的岩浆结晶分异型矿床。灰石山地区碱性正长质岩浆为稀土铌多金属矿床的形成提供了物质来源。
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| 关 键 词： | 稀土铌矿床 成矿模式 阿拉善地区 灰石山 |
| 收稿时间： | 2020-03-30 |
Geological characteristics and genesis of the REE-Nb polymetallic deposit in Huishishan of Ejinaqi in Inner Mongolia |
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| Authors: | CHEN Haidong WANG Zhanfu LU Ning ZHANG Haifeng XIE Jianxi |
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| Institution: | Inner Mongolia Institute of Geological Survey and Mineral Exploration, Hohhot 010010, China |
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| Abstract: | Huishishan REE-Nb polymentallic deposit located in the northern margin of Alxa Massif ang is a large-scale REE-Nb polymetallic deposit discovered in recent years. Through the systematic trench drilling, field geological investigation and petrographic study, the authors investigated the genesis and the ore-forming materials source of this REE-Nb deposit. The deposit is closely related with the alkali syenite and is of two different genetic types respectively magmatic crystallization differentiation type and hydrothermal metasomatism type. The metallogenic model was establieshed by summarizing the prospecting criteria of the deposit. The hydrothermal metasomatic deposit was controlled by faults, and the syenite magma was passively emplaced along faults. Then the fluid emerged out of the melt, with the further drastic drop of the temperature and pressure. The siliceous fluid rich in Nb, REE and volatile elements (mainly F and Cl) reacted with wall rocks, and finally the REE-Nb deposits were formed in favorable places. The alteration degree of limonization, pyritization and silicification in the wall rocks of the deposit is positively related to the contents of rare earth and niobium, and the boundary between the ore body and wall rocks is not obvious. The syenite magma was proactively emplaced along faults, with crystallization differentiation. The incompatible elements (Nb, REE, etc.) enriched in the residual melt and formed the magmatic crystallization differentiated deposit in the syenite. The alkaline syenite magmatism in Huishishan area provides material source for the formation of REE-Nb polymetallic deposit. |
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| Keywords: | REE-Nb deposit ore-forming model Alxa area Huishishan |
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