摘要
陕西省陈家坝铜铅锌多金属矿床是勉(县)—略(阳)—阳(平关)三角地区新发现的铜铅锌多金属矿床,通过对矿石及矿区地质体的微量与稀土元素地球化学对比分析,对陈家坝铜铅锌多金属矿床进行了成矿流体特征与成矿机制研究。研究表明,矿石富集LREE、Th/La、Nb/La、Hf/Sm值均小于1,指示成矿流体以富Cl为主。矿石的稀土元素配分曲线、微量元素蛛网图及含量类似于赋矿层位硅化白云岩,推断矿石为同生沉积成矿。矿石显示Ce负异常及Eu正异常,与海底高温热液及其沉积物的稀土元素组成和变化特征相似,反映了矿石与海底热流体及其沉积物形成过程相似,说明该区矿石形成于还原环境,成矿过程中岩浆流体、热卤水与海水组成的混合流体使其更有利于成矿。因此,认为成矿流体具有岩浆流体混合热卤水与海水的特征,流体之间的混合作用与水-岩作用是导致铜铅锌等成矿元素富集、沉淀的重要机制。
The Chenjiaba deposit is a new Cu-Pb-Zn polymetallic deposit discovered in MianxianLueyang-Yang Pingguan triangle area,Shaanxi Province.Based on the geochemical comparison between trace elements and rare earth elements in ore and geological bodies,the ore-forming fluid characteristics and metallogenic mechanism of this deposit have been studied.The result showsthat the ore in this deposit is rich in LREE,the Th/La,Nb/La and Hf/Sm ratios are all less than1,respectively,indicting the geochemical feature of ore-forming fluid mainly enriched in Cl element.The ore has similar REE distribution curve,trace element cobweb diagram and element content with the silicified dolomite in ore-bearing horizon,suggesting that the ore formed by syngenetic sedimentary mineralization.The ore has negative Ce anomalies and positive Eu anomalies,which is similar to those of seafloor hydrothermal fluids and their sediments,indicating that the ore formed in a reducing environment.In the process of mineralization,the mixture of magmatic fluid,hot brine and sea water makes it more favorable for mineralization.Therefore,it is considered that the ore-forming fluid has the geochemical characteristics of the magmatic fluid mixed with hot brine and seawater.The fluid mixing action and the water rock interaction are important mechanisms for the enrichment and precipitation of Cu,Pb and Zn ore-forming elements.
作者
丁坤
梁婷
王瑞廷
栾燕
张天运
杨秀清
李永勤
DING Kun1,LIANG Ting1,2,WANG Ruiting3,1,LUAN Yan1,2,ZHANG Tianyun4,YANG Xiuqing1,2,LI Yongqin4(1. School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,Shaanxi, China; 2. The Laboratory of Mineralization and Dynamics,Chang’an University,Xi’an 710054,Shaanxi,China;3. Northwest Nonferrous Geological Mining Group Limited Company,Xi？an 710054,Shaanxi,China; 4. Hanzhong No. 711 Geological Team,Northwest Nonferrous Geological Mining Group Limited Company, Hanzhong 723000,Shaanxi,China)
出处
《西北地质》
CAS
CSCD
北大核心
2018年第3期93-104,共12页
Northwestern Geology
基金
中国地质调查局项目"中国矿产地质与成矿规律综合集成和服务"(DD20160346)
中国地质调查局地质调查项目"秦岭-大巴山-大别山成矿规律及找矿方向研究"(1212011220869)
国家重点研发计划项目"深地资源勘查开采"专项(2017YFC0602701)"
关键词
稀土元素
微量元素
成矿流体来源
陈家坝
陕西
rare earth elements
trace elements
source of ore-forming fluids
Chenjiaba
Shaanxi
