摘要
黔北务川、沿河地区是贵州碳酸盐岩中充填交代型萤石(重晶石)矿主要分布区,主要赋存在奥陶系桐梓组和红花园组碳酸盐岩内,多与重晶石共生。矿体分布严格受地层与北西向张性断裂控制。尽管前人对黔北地区萤石矿做了大量研究,然而对于其成矿物质来源及流体特征仍然存在争论。本文选择正安土坪地区姚树坪、大田萤石矿点开展微量及稀土元素地球化学研究。结果表明,所有萤石样品Ba、Sr、Y相对上地壳富集程度高,相对亏损Rb、Nb、Zr、Hf。所有萤石样品具有相似的稀土配分模式,曲线呈略微左倾趋势的重稀土富集型,且具有明显的Eu正异常与Ce负异常特征,说明正安土坪地区萤石为同源形成的产物。不同类型的萤石矿脉具有相似的Sm/Nd比值,说明它们具有相似的物源源区,而萤石矿脉的Sm/Nd比值略微大于赋矿围岩及蚀变围岩的Sm/Nd比值,指示萤石矿的成矿物质可能来源于深部。不同颜色萤石均显示出正Eu异常和负Ce异常,表明成矿流体有建造水的加入。
The Wuchuan and Yanhe areas in northern Guizhou are the main distribution areas of infill metasomatized fluorite(barite)deposits in the carbonate rocks of Guizhou,which are mainly occurred in the carbonate rocks of Tongzi formation and Honghuayuan formation in the Ordovician,and are mostly symbiotic with barite.The distribution of ore bodies is strictly controlled by strata and NW-trending tensile faults.Although a lot of research has been done on fluorite deposits in northern Guizhou,there are still controversies about the source of minerals and fluid characteristics.In this paper,the geochemical composition characteristics of fluorite and surrounding rock samples were analyzed on the trace and rare earth element such as Yaoshuping and Datian in the Tuping area of Zheng’an.The results showed that all fluorite samples had a high degree of relative crustal enrichment in Ba,Sr and Y,and a relative loss of Rb,Nb,Zr and Hf.All fluorite samples have a similar rare earth distribution pattern,that is,the light rare earth is relatively lost,the heavy rare earth is relatively enriched,and there are obvious positive anomalies of Eu and negative anomalies of Ce,indicating that the fluorite in the Tuping area of Zheng’an is a product formed at the same time.Different types of fluorite veins have similar Sm/Nd ratios,indicating that they have similar provenance areas,while the Sm/Nd ratio of fluorite veins is slightly larger than that of ore-bearing and altered surrounding rocks,indicating that the mineralization of fluorite ore may come from deep sources.All fluorites in the study area have both positive and negative Eu anomalies,which indicate that the metallogenic thermal fluid and the lower temperature seawater have mixed.
作者
石珉
陈兴
吴开彬
刘雨
邓贵标
樊洪富
刘奎勇
黄雄伟
吴滔
SHI Min;CHEN Xing;WU Kai-bin;LIU Yu;DENG Gui-biao;FAN Hong-fu;LIU Kui-yong;HUANG Xiong-wei;WU Tao(Guizhou Geologcal Survey,Guiyang 550081,Guizhou,China;Key Laboratory of Strategic Mineral Intelligent Exploration of Guizhou,Guiyang 550081,Guizhou,China;Geology and Mineral Resources Central Laboratory of Guizhou,Guiyang 550018,Guizhou,China)
出处
《贵州地质》
2025年第1期49-59,共11页
Guizhou Geology
基金
贵州省新一轮找矿突破战略行动项目《贵州1∶5万太白幅(H48E022021)、乐俭幅(H48E022022)、土坪幅(H48E023022)、旺草幅(H48E024022)矿产地质调查》(黔自然资函﹝2022﹞632号)
贵州省科技计划项目[黔科合基础-ZK[2022]一般081]
黔地矿科合(2024)TD004联合资助。
关键词
成矿物质来源
成矿流体
元素地球化学特征
萤石矿
正安地区
Source of minerals
Ore-forming fluids
Elementary geochemical characterization
Fluorite mines
Zheng’an area
