滇东南老寨湾金矿床主微量元素迁移及稀土元素地球化学特征  

Characteristics of major and trace element migration REE geochemistry of Laozhaiwan gold deposit,Yunnan province

作　　者：赵德坤[1] 代鸿章 魏宇[1] 艾金彪[1] 柳维[1] ZHAO Dekun;DAI Hongzhang;WEI Yu;AI Jinbiao;LIU Wei(Sichuan Institute of Metallurgical Geology&Exploration,Chengdu 610051,China;MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resource,CAGS,Beijing 100037,China)

机构地区：[1]四川省冶金地质勘查院,成都610051 [2]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037

出　　处：《地质找矿论丛》2019年第4期529-537,共9页Contributions to Geology and Mineral Resources Research

基　　金：国家自然科学基金项目（编号：40930423,41372093,41171302）资助

摘　　要：老寨湾金矿床位于扬子地台西南缘与华夏地块结合部位的南盘江造山褶皱带文山-富宁断褶束西畴拱凹北缘。矿体主要赋存于下泥盆统坡松冲组下段(D1ps1)石英砂岩、石英岩,硅化石英细砂岩、石英细砂岩中。本文运用Gresens和Grant提出的蚀变岩成分、体积公式和Ci0-CiA图解法,对老寨湾金矿床岩(矿)石形成过程中主要元素迁移规律进行了研究,结果表明:1)石英砂岩在硅化过程中,SiO2和As被带入,Au被带出进入流体;在氧化矿形成过程中,SiO2和Au被带入;而在黄铁矿化矿石形成过程中,As、Au、FeO和Fe2O3被带入,SiO2被带出。2)矿区各类岩(矿)石稀土元素分布模式图均呈右倾型式,为轻稀土富集型;氧化型岩(矿)石、硅化型岩(矿)石和石英砂岩的稀土元素分布型式类似,均表现为负铕异常,无明显的铈异常。3)黄铁矿化型矿石稀土元素分布模式图中样品分为2类:沉积成因和热液成因;沉积成因黄铁矿化型矿石含金低,w(ΣREE)值高,表现为负铕异常;热液成因黄铁矿化型矿石含金较高,w(ΣREE)值低,表现为正铕异常。4)黄铁矿化型矿石w(ΣREE)值明显低于其它几类岩矿石,说明热液型黄铁矿化型矿石的形成可能与矿区辉绿岩脉相关,表现出了深源的特征。Laozhaiwan gold deposit is located in the northern rim of Xichou arch of the Wenshan-Funing fault-fold bundle of Nanpanjiang orogenic blet at the joint of southwest margin of Yangtz platform and the Cathaysia block.Studies on the characteristics of Laozhaiwan gold deposit showed that ore bodies mainly occurred in quartz sandstone,quartzite,silicified quartz fine sandstone,quartz fine sandstone of the lower Posongchong formation(D1ps1).In this paper altered rock composition-volume formula and Ci0-CiA plot proposed by Gresens and Grant are used to study the migration law of major elements in the rock and ore formation process.The result shows that 1)during silicification SiO2 and As are introduced to the sandstone and Au move out of the sandstone with hydrothermal fluid;during oxidation SiO2 and Au into the sandstone;during formation of pyritization ore As、Au、FeO and Fe2O3 into the sandstone and SiO2 out of the sandstone;2)REE pattern of each rock and ore are all characterized by right decline phenomenon with enrichment of LREE;REE pattern of oxidized rock and ore,silicified rock and ore and quartz sandstone similar and characterized by negative Eu anomly;3)Samples of pyritized rock and ore show two REE patterns representing the sedimentary pyrite and hydrothermal pyrite and Au value is lower with the former and the former characterized by high w(ΣREE)and negative Eu anomly,Au higher with the latter and the latter by low w(ΣREE)and positive Eu anomly;4)w(ΣREE)value of the pyritized ore is apparently lower than the other ore types that reflects such ore is possibly related to diabase dyke in the area.

关 键 词：寨湾金矿 元素迁移 稀土元素 卡林型金矿床 云南省 

分 类 号：P595[天文地球—地球化学] P618.51[天文地球—地质学]