投稿时间：2020-06-10
修订日期：2020-11-16
网络发布日期：2021-01-08
中文摘要:华北克拉通破坏及其成矿事件已引起地学界的广泛关注，其中张宣地区是华北克拉通的重要金矿集中区之一，通过对张宣地区大白阳金矿成矿类型、成矿深度及剥蚀保存的探讨，为区内深部找矿提供了重要的参考依据。文章通过流体包裹体研究对大白阳金矿成矿温度及成矿深度进行计算，利用矿物压力计对矿区周边岩体侵位深度进行估算。流体包裹体研究结果显示大白阳金矿成矿温度160~220℃、盐度w（NaCleq）=9%~15%，密度0.78~0.97 g/cm3、压力46.3~104.6 MPa，成矿流体主要属于NaCl-H2O体系，成矿过程中流体温度和盐度都呈现明显的降低趋势。采用黑云母压力计，针对大白阳金矿周边谷嘴子、杨家营以及前坝口花岗质岩体的侵位深度进行估算，并对大白阳金矿自形成以来的剥蚀保存情况进行了探讨，估算结果显示，谷嘴子岩体（236.0 Ma）成岩深度7.02 km、杨家营岩体（138.6 Ma）成岩深度2.66 km、前坝口岩体（140.2 Ma）成岩深度3.13 km。结合前人的裂变径迹结果，认为张宣地区自中生代以来剥蚀速率为0.022~0.029 km/Ma，剥蚀量为3 km。按照前述成矿压力46.3~104.6 MPa换算，大白阳金矿成矿深度6.93 km，剥蚀量小于矿床成矿深度，说明该矿深部仍具有良好的找矿前景。
Abstract:The destruction of the North China craton and its metallogenic events have attracted wide attention in geosciences. Zhangxuan area is one of the important gold ore concentration areas in the North China craton. The discussion on the metallogenic type, mineralization depth and denudation preservation of the Dabaiyang gold deposit in Zhangxuan area provided an important reference for deep prospecting in this area. Fluid inclusions were used to calculate the mineralization temperature and depth of the Dabaiyang gold deposit, and mineral pressure gauge was used to estimate the emplacement depth of surrounding rocks. The research results of ore-forming fluid inclusions of the Dabaiyang quartz vein type gold deposit show that, according to the ore-forming temperature (160~220℃), the salinity (w(NaCleq)=9%~15%), the density (0.78~0.97 g/cm3) and the pressure (46.3~104.6 MPa), the ore-forming fluid mainly belongs to NaCl-H2O system, and that, during the process of mineralization, the fluid temperature and salinity both showed a clear decreasing trend. With biotite manometer, the emplacement depth of Guzuizi, Yangjiaying and Qianbakou granitoids around the Dabaiyang gold mine was estimated, and the denudation and preservation of the Dabaiyang gold deposit since its formation were discussed. the results show that the depth of formation of Guzuizi (236.0 Ma) was 6.93km, that of Yangjiaying (138.6 Ma) was 3.01 km and that of Qianbakou (140.2Ma) was 3.13 km. Combined with the results of fission tracks obtained by the previous researchers, it is believed that the erosion rate of Zhangxuan area since the Mesozoic period has been 0.022~0.029 km/Ma, and the erosion amount has been 3km. According to the above-mentioned conversion of ore-forming pressure 46.3~104.6 MPa, the ore-forming depth of the Dabaiyang gold deposit was 6.93 km and the denudation amount was less than the mineralization depth of the deposit, which indicates that the deep part of the deposit still has a good ore-search prospect.
keywords:geochemistry fluid inclusion biotite manometer deposit denudation and preservation Dabaiyang gold deposit Zhangxuan area
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基金项目:本文得到国家重点研发计划“华北东部金成矿区域差异性”（编号：2016YFC0600106）项目资助
引用文本：
徐渴鑫,申俊峰,李胜荣,黄绍峰,张士全,王业晗.2020.张宣地区大白阳金矿床包裹体特征及矿床剥蚀保存[J].矿床地质,39(6):1030~1048XU KeXin,SHEN JunFeng,LI ShengRong,HUANG ShaoFeng,ZHANG ShiQuan,WANG YeHan.2020.Characteristics of fluid inclusions in Dabaiyang gold deposit of Zhangxuan area and its erosion preservation of deposit[J].Mineral Deposits39(6):1030~1048
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