铜陵新桥Cu-S-Fe矿床下盘石英黄铁矿脉石英流体包裹体Rb-Sr同位素定年  

Rb-Sr Isotope Dating of the Fluid Inclusions in Quartz from Quartz—Pyrite Veins in the Footwall of Xinqiao Cu-S-Fe Deposit,Tongling

作　　者：张宇[1,2] 邵拥军[1,2] 全伟[1,2] 刘忠法[1,2] 刘清泉[1,2,3] 

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,长沙410083 [2]中南大学地球科学与信息物理学院,长沙410083 [3]河南省有色金属矿产探测工程技术研究中心,郑州450016

出　　处：《地质论评》2015年第5期1168-1176,共9页Geological Review

基　　金：中南大学"创新驱动计划"项目;国土资源部公益性行业科研专项经费项目04课题(编号200911007-04);中南大学地球科学与信息物理学院教育部重点实验室"有色金属成矿预测"专项基金;中南大学中央高校基本科研业务费专项基金(2013zzts056)成果

摘　　要：为了探讨新桥Cu—S—Fe矿床的形成是否经历过海西期海底喷流沉积成矿作用,在详细的野外调研和室内工作基础上,对层状矿体下盘石英黄铁矿脉中的石英流体包裹体进行Rb-Sr同位素定年分析。研究结果表明:下盘石英黄铁矿脉中的石英流体包裹体Rb-Sr等时线年龄为138.0±2.3Ma(MSWD=5.4),与矶头复式岩株的成岩年龄相近(140.4±2.2Ma),而且下盘网脉状矿化石英流体包裹体中流体的n(^(87)Sr)/n(^(86)Sr)初始值(0.71138±0.00014)和矶头岩株的n(^(87)Sr)/n(^(86)Sr)初始比值相近,说明下盘网脉状矿化为岩浆热液成因,并非为海西期海底喷流通道。与典型海底喷流沉积矿床进行地质特征对比分析也发现,新桥Cu—S—Fe矿床地质特征有别于典型的海底喷流沉积矿床。综合分析认为,新桥Cu—S—Fe矿床应属于燕山期岩浆热液矿床。In order to investigate whether Xinqiao Cu-S-Fe deposit experienced Hercynian Sedex mineralization,Rb-Sr isotope analysis of fluid inclusion in quartz from stockwork mineralization of footwall in Xinqiao Cu-S-Fe deposit,based on detailed field investigation and laboratory work.The results indicate that the Rb-Sr isochron age of fluid inclusion in quartz from stockwork mineralization of footwall is 138.0±2.3Ma（MSWD =5.4）,close to the weighted average age of zircons in Jitou Rock Strain （140.4 ± 2.2Ma）,and the 87Sr/86Sr initial value is 0.71138 ± 0.00014,close to the one of Jitou Rock Strain.Form the dating data,we get that stockwork mineralization of footwall formed for magmatic hydrothermal,not for the Sedex mineralization in Hercynian.The comparison between typical Sedex type deposit and Xinqiao Cu-S-Fe deposit suggests that the geological characteristics of Xinqiao Cu-S-Fe deposit is different form typical Sedex deposit,obviously.Comprehensive analysis shows that Xinqiao Cu-S-Fe deposit didn＇t experience Sedex mineralization in Hercynian.

关 键 词：RB-SR等时线年龄 石英流体包裹体 下盘石英黄铁矿脉 新桥Cu-S-Fe矿床 铜陵 

分 类 号：P618.2[天文地球—矿床学] P597.3[天文地球—地质学]