投稿时间：2019-08-06
修订日期：2019-09-16
网络发布日期：2019-11-04
中文摘要:白云鄂博是世界第一大稀土元素矿床，其稀土元素资源量占世界目前已知稀土元素资源总量的三分之二以上，具有重要的经济和战略地位。白云鄂博自1927年发现至今已有92年，对其的开发和研究历史悠久，在赋矿碳酸岩的成因、成矿年代、稀土矿物学等方面取得了一系列重要进展，为碳酸岩型稀土元素成矿理论发展做出了突出贡献。由于矿床经历了成矿后复杂的构造变形和热液蚀变，致使其地质、地球化学特征复杂，学界对其成因和成矿过程一直存在不同认识，对成矿碳酸岩的岩浆演化、稀土元素迁移与富集机理等方面的研究也相对薄弱。笔者最新研究表明，矿区过去被认为是下白云鄂博群的H1、H2、H9岩石单元并非沉积变质岩或变质火山岩，而应为岩浆侵入成因，矿区其他岩石单元（H3~H7）的成因也值得商榷。H9岩石单元中的黑云母岩（前人称为黑云母板岩）和富含黑云母的碳酸岩（前人称为暗色板岩）为成矿碳酸岩的一部分，是碳酸岩不同岩相带的表现。黑云母岩和富黑云母碳酸岩相对于含矿碳酸岩具有相对低的稀土元素含量和轻、重稀土元素比值，表明岩浆演化可能对稀土元素的富集和分异具有重要贡献。矿区主要岩石单元成因的新认识不仅为矿床成因、成矿背景研究提供了新的依据，同时也为研究区域构造演化、正确厘定矿区构造式样和指导矿区深部和外围找矿提供了新的思路。
中文关键词:地球化学 碳酸岩型稀土元素矿床 研究进展 新认识 白云鄂博
Abstract:As the world's largest rare earth elements (REEs) deposit, the Bayan Obo REE-Nb-Fe deposit accounts for more than two-thirds of the world's REEs resources, and play an important role in REEs resource economy and strategy. Since its discovery in 1927, the Bayan Obo has been exploited and studied for 92 years. Many discoveries and hypothesis involving the genesis of the deposit have been proposed and which improve the understanding to carbonatite related REEs metallogeny. However, because of the intensive post-ore deformation, metamorphism and hydrothermal alteration, the geological and geochemical characteristics of the Bayan Obo is very complex, leading to the long term controversy about the ore genesis. In addition, the knowledge about the magmatic evolution of carbonatite and the mechanics of REE transport and enrichment is lacking. Our new petrological and mineralogical results indicate that the H9, H2 and H1 lithological units in the area may have a magmatic intrusive origin, but they have long been regarded as metamorphic sedimentary rock or volcanic rock by previous researchers. Biotitite (previously known as biotite slate) and biotite-rich carbonatite (previously known as dark slate) of the H9 unit are intrusive magmatic rocks, comprising the outer zone of silicate-carbonatite complex. The petrogenesis of other lithological units (H3~H7) in the area is still debate. Our new understanding of above-mentioned petrogenesis and lithofacies zonation provide innovative insight for magmatic evolution of REE-host carbonatite and the mechanism controlling REEs enrichment. Comparing with the REEs host carbonatite (H8 unit), the biotitite and biotite-rich carbonatite of outer zone have lower total REEs content and LREE/HREE ratios, indicating that the magmatic evolution might have play an important role in enrichment of REEs and fractionation between LREE and HREE. The possible magmatic origin of H1~H9 also lead to re-understanding of the structure pattern of the deposit and provide significant guidance for effective mineral exploration.
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基金项目:本文得到国家自然科学基金项目（编号：41472072、41072066）和国际地学对比计划项目（编号：IGCP/SIDA-600）的联合资助
引用文本：
谢玉玲,曲云伟,杨占峰,梁培,钟日晨,王其伟,夏加明,李必成.2019.白云鄂博铁、铌、稀土矿床：研究进展、存在问题和新认识[J].矿床地质,38(5):983~1003XIE YuLing,QU YunWei,YANG ZhanFeng,LIANG Pei,ZHONG RiChen,WANG QiWei,XIA JiaMing,LI BiCheng.2019.Giant Bayan Obo Fe-Nb-REE deposit: Progresses, Controversaries and new understandings[J].Mineral Deposits38(5):983~1003
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