摘要
镇旬盆地是南秦岭构造带中部的早古生代断陷盆地,近年在盆地中部发现多处微细浸染型金矿床(包括小河、惠家沟、王庄等),查明矿床中金的赋存状态对揭示区域金成矿富集机制具有重要的意义。笔者以王庄、老君庙两个微细浸染型金矿床为研究对象,通过系统的镜下鉴定和EPMA分析进行成因研究。区内金矿床均表现出低品位、载金矿物为金属硫化物等特征,区域内主要发育3类与金成矿密切相关的黄铁矿:无砷黄铁矿(Py1、 Py2)、含砷黄铁矿(毒砂)(Py3、Apy)、贫砷黄铁矿(Py4),Au元素的富集主要位于Py2之后。成矿期黄铁矿Co/Ni值主要为1~10,为热液成因,且与含砷热液加入有关。此外,结合Au-As关系,初步判断区内微细浸染型金矿床中金元素主要以晶格金形式赋存于黄铁矿、毒砂中。
The Zhen’an-Xunyang basin,an Early Paleozoic rifted basin situated in the central part of the South Qinling tectonic belt,has seen the discovery of several disseminated gold deposits,like Xiaohe,Huijiagou,and Wangzhuang in recent years.Understanding the occurrence state of gold in these deposits is crucial for uncovering the regional gold mineralization enrichment mechanism.This study focuses on two fine-disseminated gold deposits,Wangzhuang and Laojunmiao,by carrying out the systematic microscopic identification and EPMA analysis.These gold deposits exhibit low-grade and metallic sulfide-hosted mineralization.Three types of pyrite closely associated with gold mineralization are identified in the region:arsenic-free pyrite(Py1,Py2),arsenicbearing pyrite(arsenopyrite)(Py3,Apy),and arsenic-poor pyrite(Py4),with gold enrichment mainly observed after Py2.The Co/Ni ratios of the ore-forming pyrite during the mineralization period typically fall between 1 to 10,indicating a hydrothermal origin linked to the influx of arsenic-bearing hydrothermal fluids.Furthermore,based on the Au-As relationship,it is tentatively suggested that gold elements in the fine-disseminated gold deposits in the area are primarily present in lattice gold form within pyrite and arsenopyrite.
作者
孟五一
魏立勇
高永宝
张振
田映天
李先晨
吴欢欢
郝迪
贾彬
Belt MENG Wuyi;WEI Liyong;GAO Yongbao;ZHANG Zhen;TIAN Yingtian;LI Xianchen;WU Huanhuan;HAO Di;JIA Bin(Xi'an Center of Mineral Resources Survey,China Geological Survey,Xi’an 710199,Shaanxi,China)
出处
《西北地质》
北大核心
2026年第1期97-109,共13页
Northwestern Geology
基金
深地国家科技重大专项(2025ZD1009603-1)
自然资源综合调查指挥中心科创基金(KC20240008、KC20240007)
陕西省自然科学基础研究计划项目(2023-JC-QN-0363、2024JC-YBQN-0349)
中国地质调查局项目(DD20230206504)联合资助。
关键词
金的赋存状态
黄铁矿
微细浸染型金矿
南秦岭
gold occurrence
pyrite
micro-disseminated gold deposits
South Qinling
