摘要
安徽铜官山矽卡岩型铜铁矿床富含多种稀有贵金属金银铂钯和铀,本文应用偏光显微镜与电子探针技术对该地区贵金属和铀矿物的含量、矿物种类、赋存状态及其嵌布特征进行研究,并利用电子探针Th-U-Pb定年技术推测铀矿物的形成时期。研究表明:金主要以银金矿独立矿物存在,成色均值约为638,与铜的硫化物密切依存,金矿物形成于成矿中晚期的中低温环境;银的独立矿物有银金矿、碲银矿、辉银矿,还与铜铋铅等以类质同象形式结合形成不同种类的矿物组合,且含量在74.15%~0.12%不等;铂钯矿物以含铂碲钯矿为主;铀以晶质铀矿独立矿物存在且与磁铁矿密切依存,晶质铀矿的形成年龄约为124±14 Ma,晚于岩体形成年龄(约139 Ma),早于黄铜矿和含金银铂钯等矿物,而与磁铁矿同在燕山中晚期形成。结合镜下观察,认为铜官山矽卡岩型铜铁矿床主要矿物生成顺序依次是:石榴子石-磁铁矿、晶质铀矿,含金银铂钯矿物,黄铜矿。本研究为贵金属选矿提供了线索,同时利用晶质铀矿的年龄数据界定了伴生贵金属的形成年代。
Many associated metals such as Au,Ag,Pt,Pd,and U have been found in the skarn type copper-iron deposit of Tongguanshan in Anhui. Combining microscope and Electron Microprobe( EPMA),the occurrence and distribution characteristics of these elements and calculations of the formation age of U-bearing minerals using EPMA for the first time is reported in this paper. The results show that Au exists as electrum and is related to copper sulfides and the average quality of gold is 638,indicating that gold minerals may have formed in the low temperature environment at the middle-late mineralization period. Ag occurs in different minerals and as the form of isomorphism of Cu,Te,Bi,Pb with Ag content from 74. 15% to 0. 12%. Pt and Pd occur as independent minerals such as platinum-bearing merenskyite. U occurs as uraninite and is associated with magnetite or occurs in the cracks of magnetite. Based on the Th-U-Pb system,the formation age of uraninite is 124 ± 14 Ma,later than the rock( about 139 Ma),but earlier than the formation of copper and other minerals containing Au,Ag,Pt,Pb.Combining with the geological characteristics it is likely that uraninite and magnetite formed at the same time.Microscope observation shows that the paragentic sequence of minerals is garnet magnetite,uraninite,and minerals containing Au,Ag,Pt,Pd,and copper sulfides. This study provides clues for precious metal dressing,and the age of uraninite can constrain the formation age of the associated precious metals.
出处
《岩矿测试》
CAS
CSCD
北大核心
2015年第2期187-193,共7页
Rock and Mineral Analysis
基金
中国地质调查局地质调查工作项目(12120113014500)
关键词
偏光显微镜
电子探针
铜官山
矽卡岩型铜铁矿床
伴生元素
赋存状态
贵金属
晶质铀矿
microscope
Electron Microprobe(EPMA)
Tongguanshan
the skarn type copper-iron deposit
associated elements
occurrence
precious metals
uraninite