摘要
热液型重晶石因其高品质而成为近些年的重点勘查对象。位于扬子克拉通中部的武陵-苗岭一带是我国主要的热液重晶石成矿区,已成为重要钡资源基地。近些年,在贵州黔北新发现了受上寒武统娄山关群白云岩与下奥陶统桐梓组底部页岩接触部位控制的重晶石矿体,矿体延伸稳定,具有较大的成矿潜力,但其特殊热液成矿机制尚未开展系统研究,制约了进一步的勘查部署工作。以贵州余庆地区热液型重晶石为研究对象,开展了系统的岩相学、主微量元素地球化学和硫同位素组成分析研究。野外地质调查表明,硅(碎屑岩)-钙(白云岩)界面产生的层间破碎带及张性裂隙是该区重晶石的主要控矿构造。元素地球化学分析表明,围岩白云岩样品δCe呈现无异常特征(平均1.06),而重晶石样品呈明显的δCe负异常(平均0.66),揭示重晶石在氧化条件下形成。(Cu+Zn)与Sr元素协变关系和Y/Ho比值指示成矿物质可能来自寒武系富Ba的碳酸盐岩(含膏岩)地层。同样重晶石硫同位素组成(δ34SVCDT为30.94‰~41.27‰)也指示硫主要来自寒武系海相蒸发岩。综合前人研究认为,构造运动驱使盆地流体发生运移,并萃取富Ba蒸发岩地层,在层间断层(硅-钙界面)与大气降水混合,形成重晶石矿床。研究成果为重晶石矿床的勘查提供重要参考。
[Objective]Hydrothermal barite deposits are the main exploration targets for barium.The Wuling-Miaoling area,located in the middle part of the Yangtze Craton,contains abundant hydrothermal barite deposits.In recent years,some barite orebodies have been discovered within the interlaminar fracture zone between the Upper Cambrian Loushanguan Formation and the Lower Ordovician Tongzi Formation in the region.These orebodies,which exhibit stable extension,have significant metallogenic potential.However,the genesis of the barite deposits in the Yuqing area is poorly understood,leading to ambiguity regarding further ore exploration.[Methods]In this study,we investigate the barite deposits in the Yuqing area and present a metallogenic model based on detailed petrographic observations and major/trace elements and sulfur isotopic analyses.[Results]Results show that the interlayer fracture zone and tensile fractures generated by the silica-calcium interface are the main ore-controlling structures for barite in this area.The geochemistry of barite shows that theδCe of the wall rocks(dolomite)is normal.In contrast,the negativeδCe anomaly(mean value is 0.66)in the barite samples indicates that barite was formed under oxidation conditions.The(Cu+Zn)vs.Sr,Y/Ho ratios,and sulfur isotopes suggest that the oreforming materials(S and Ba)originated from marine evaporites in the Cambrian.Based on previous studies,we propose that the tectonic event drove the migration of basinal fluids,extracting the Ba-rich evaporite strata.The mixing of these fluids with meteoric water led to the precipitation of barite along the interlayer faults(silica-calcium interfaces).[Conclusion]The research results provide an important reference for the exploration of barite deposits.
作者
李源洪
杜红毅
陈军
徐石辉
胡涛
袁清松
LI Yuanhong;DU Hongyi;CHEN Jun;XU Shihui;HU Tao;YUAN Qingsong(106 Geological Brigade of Guizhou Provincial Bureau of Geology and Mineral Exploration and Development,Zunyi Guizhou 563000,China;College of Geosciences,China University of Geosciences(Wuhan),Wuhan 430074,China;College of Natural Resources,China University of Geosciences(Wuhan),Wuhan 430074,China;College of Resources and Environmental Engineering,Ministry of Education,Guizhou University,Guiyang 550025,China;Key Laboratory of Karst Geological Resources and Environment,Ministry of Education,Guizhou University,Guiyang 550025,China)
出处
《地质科技通报》
北大核心
2025年第3期122-133,共12页
Bulletin of Geological Science and Technology
基金
贵州省地质矿产勘查开发局地质科研项目(黔地矿科合[2022]9号)。
关键词
主微量元素
硫同位素
热液重晶石矿床
余庆地区
贵州
层间破碎带
major and trace element
sulfur isotope
hydrothermal barite deposit
Yuqing area
Guizhou Province
interlaminar fracture zone
