冀北招素沟萤石矿地球化学特征及矿床成因探讨  

Geochemical characteristics and genesis of the Zhaosugou fluorite deposit,northern Hebei Province

作　　者：代晓光[1] 商朋强 张成信[1] 梁中朋 王锦鹏 李健[1] 杨海波 聂新明 DAI Xiao-guang;SHANG Peng-qiang;ZHANG Cheng-xin;LIANG Zhong-peng;WANG Jin-peng;LI Jian;YANG Hai-bo;NIE Xin-ming(Institute of Geology,China Bureau of Chemical Geology and Mine,Beijing 100101,China;China Bureau of Chemical Geology and Mine,Beijing 100013,China;Hebei Chemical Geological Prospecting Institute,China Bureau of Chemical Geology and Mine,Shijiazhuang 050031,China)

机构地区：[1]中化地质矿山总局地质研究院,北京100101 [2]中化地质矿山总局,北京100013 [3]中化地质矿山总局河北地质勘查院,河北石家庄050031

出　　处：《岩石矿物学杂志》2021年第1期27-38,共12页Acta Petrologica et Mineralogica

基　　金：中国地质调查局资助项目(DD20160057,DD20190086)。

摘　　要：招素沟萤石矿是冀北地区较为典型的萤石矿,矿床产于张家口组火山岩及早白垩世正长斑岩的断裂构造中,其矿体的产出严格受断裂控制。对萤石矿石及围岩的微量元素及稀土元素进行了系统分析。微量元素分析结果显示所有样品均表现出较高的Co、Cr、Cu、Ni含量,且变化较稳定,特别是Ni的含量明显偏高;U、Be、Mo含量较低,变化较大;萤石矿稀土元素分布模式表现为右倾的轻稀土富集型,Eu既有正异常又有负异常,Ce表现为轻微的负异常。流体包裹体主要为富液包裹体及纯液体包裹体两种形式,包裹体测温显示,完全均一温度为137~238℃,均一温度较为集中,平均189℃,盐度(Na Cleq,质量分数)为0.88%~2.07%,平均1.61%,密度为0.63~0.89 g/cm3,总体反映招素沟萤石矿的成矿流体是一种较均一的中低温、低盐度、低密度的流体。根据成矿压力估算出成矿深度为0.289~0.538 km,平均0.428 km。通过对矿石与围岩的地球化学及成矿流体包裹体特征研究,认为该萤石矿系中低温热液成因。The Zhaosugou fluorite deposit is a typical fluorite deposit in Longhua area.The deposit is located in the fault structure of volcanic rocks of Zhangjiakou Formation and early Cretaceous syenite porphyry.The occurrence of its orebody is strictly controlled by faults.Trace elements and rare earth elements in fluorite ores and surrounding rocks were systematically analyzed.Trace elements show that all samples have relatively high Co,Cr,Cu and Ni content,and the changes are stable,especially the Ni content is obviously higher.The values of U,Be and Mo are low and vary greatly.The distribution pattern of rare earth elements in fluorite ore shows a rightward light rare earth enrichment type,with both positive and negative Eu anomalies,and Ce shows a slight negative anomaly.The oreforming inclusions are mainly liquid-rich inclusions and pure liquid inclusions.The temperature measurement of the inclusions shows that the complete homogenization temperatures are 137~238℃,and the homogenization temperatures are relatively concentrated,with an average of 189℃,the salinities are 0.88%~2.07%Na Cleq,with an average of 1.61%,and densities are 0.63~0.89 g/cm3.Overall,the ore-forming fluid of the Zhaosugou fluorite deposit was a relatively uniform low temperature,low salinity and low density fluid.According to the metallogenic pressure,the metallogenic depth is estimated to be 0.289~0.538 km,with an average of 0.428 km.The geochemical characteristics of ore and surrounding rocks and the characteristics of ore-forming fluid inclusions show that the fluorite ore system was of low-temperature hydrothermal origin.

关 键 词：招素沟 萤石矿床 地球化学 稀土元素 流体包裹体 

分 类 号：P619.215[天文地球—矿床学]