摘要
老湾金矿床位于桐柏—大别造山带北麓,是河南省最大的单体金矿床。为揭示老湾金矿成因,对老湾金矿床结构构造、岩石矿物组合、金矿物组成和赋存形式、成矿期次和成矿流体特征进行了讨论。研究表明:老湾金矿的矿石结构构造和围岩蚀变特征与小秦岭金矿和胶东金矿具有相似性,矿物组合与西秦岭造山型金矿和胶东金矿类似。老湾金矿普遍有明金的存在,此为造山带金矿的重要特征。老湾金矿可划分为4个成矿阶段,分别为石英-粗粒自形黄铁矿阶段、石英-中细粒黄铁矿阶段、石英-多金属硫化物阶段、石英-碳酸盐阶段。老湾金成矿过程中有幔源物质的加入,成矿流体富含CO2且以深源为主混合有大气水,与造山型金矿典型特征吻合。矿石硫由深源岩浆与龟山岩组地层共同提供,并且随着成矿作用进行,地层所提供的硫源逐渐增加。成矿初始阶段成矿流体为岩浆热液与大气降水的混合热液,后期大气降水含量逐渐增加。老湾金矿形成的锆石U-Pb年龄为加里东—印支期,结合矿床所处的东秦岭—桐柏—大别碰撞造山带的构造环境,认为老湾金矿为南秦岭由南向北俯冲碰撞造山带型金矿。老湾造山型金矿与胶东金矿相似,成矿深度可达3000 m,经钻探验证在垂深1534.64 m钻遇金矿体,揭示了老湾金矿深部良好的找矿前景。上述分析对于该区进一步研究成矿规律以及发现深部第二找矿空间有一定的参考价值。
Laowan Gold Deposit is located at the northern foot of Tongbai-Dabei orogenic belt and is the largest single gold deposit in Henan Province.In order to reveal the genesis of Laowan Gold Deposit,the characteristics of Laowan Gold Deposit,including the structure,mineral assemblages,composition and existing form of gold minerals,metallogenic epoch and metallogenic fluid characteristics were discussed.The following research achievements have been obtained.The ore structure and wall rock alteration characteristics of Laowan Gold Deposit are similar to Xiaoqinling Gold Deposit and Jiaodong Gold Deposit,and the mineral assemblage is similar to Western Qinling orogenic gold deposit and Jiaodong Gold Deposit.The native gold in Laowan Gold Deposit is an important feature of orogenic gold deposits.Laowan Gold Deposit can be divided into four metallogenic stages:quartz-coarse autogenous pyrite stage,quartz-medium fine pyrite stage,quartz-polymetallic sulfide stage and quartz-carbonate stage.The mantle-derived materials were added to the Laowan gold mineralization process.Metallogenic fluid is rich in CO2 and is mainly mixed with atmospheric water from deep source.They are consistent with the typical characteristics of orogenic gold deposits.The sulfur is provided by the strata of deep magma and Guishanyan formation,and with the progress of mineralization,the sulfur source provided by the strata increases gradually.In the initial stage of mineralization,the ore-forming fluid is a mixture of magmatic hydrothermal and meteoric water,and the atmospheric precipitation content gradually increases in the later period.Considering the tectonic environment of collisional orogeny in eastern Qinling-Tongbai-Dabie orogen where Laowan Gold Deposit is located,and that the U-Pb age of zircons formed in Laowan gold deposit is caledonian-indosinian period,it is believed that Laowan Gold Deposit is orogenic type gold deposit.It was caused by south Qinling from south to north subduction collision.This suggests that Laowan Orogenic Gold Deposit
作者
陈建立
陈英男
陈金铎
郭鹏
CHEN Jianli;CHEN Yingnan;CHEN Jinduo;GUO Peng(The First Geological Exploration Institute of Henan Provincial Bureau of Geo-exploration and Mineral Development,Zhengzhou 450001,China)
出处
《金属矿山》
CAS
北大核心
2021年第2期127-138,共12页
Metal Mine
基金
河南省国土资源科研项目(编号:豫国土资函[2015]258号-12)
河南省财政地质勘查项目(编号:[2018]22-11)
河南省财政地质勘查项目(编号:[2020]18-13)
河南省地矿局地质科研项目(编号:豫地矿科研[2020]4号)。
关键词
老湾金矿
造山型
碰撞造山
成因
找矿前景
Laowan Gold Deposit
orogenic
collisional orogeny
cause
prospecting potential
