豫西陈楼萤石矿床地质特征及Sm-Nd同位素年龄  

GEOLOGICAL CHARACTERISTICS AND Sm-Nd ISOTOPIC AGE OF CHENLOU FLUORITE DEPOSIT,WESTERN HENAN PROVINCE

作　　者：刘纪峰[1] 白德胜[1] 张凯涛 杨东潮[1] Liu Jifeng;Bai Desheng;Zhang Kaitao;Yang Dongchao(The Second Institute of Geology and Mineral Resources Investigation,Henan Provincial Bureau of Geology and Mineral Exploration and Development,Zhengzhou,Henan 450001,China)

机构地区：[1]河南省地质矿产勘查开发局第二地质矿产调查院,河南郑州450001

出　　处：《矿物岩石》2020年第1期69-75,共7页Mineralogy and Petrology

基　　金：河南省两权价款项目(2015-05)。

摘　　要：对陈楼萤石矿床地质特征进行归纳总结,并测定萤石的Sm-Nd同位素等时线年龄,为矿床成矿年龄、物质来源的研究及进一步找矿提供依据。陈楼萤石矿床是典型的中—低温热液裂隙充填型矿床,矿体严格受构造带控制,F2,F3,F4,F5为其主要容矿构造;主矿体自上而下具上陡—中缓—下陡的趋势,矿体平均厚度2.97 m,平均品位63.99%;矿石主要有块状、胶结状、条带状和玉髓萤石矿四种类型;围岩中常见硅化、高岭石化、绿泥石化、绢云母化等,且含矿构造自中心向两侧蚀变具有明显分带特征。测得萤石Sm-Nd同位素等时线年龄为(120±17)Ma,143Nd/144Nd初始比值0.512031±0.000026,εNd(t)=-8.8,对比前人测得太山庙岩体的SHRIMP锆石U-Pb年龄112~125 Ma,143Nd/144Nd初始比值0.511653~0.512506,εNd(t)值-16.1^-7.5,说明成矿作用发生在燕山晚期早白垩世,指示萤石成矿物质可能来源于地壳,且与太山庙岩体的成矿物质来源应一致或相近。The geological characteristics of Chenlou fluorite deposit are summarized and the Sm-Nd isochron age of fluorite is determined in order to provide basis for the study of ore-forming age,material source and further prospecting of the deposit.Chenlou fluorite deposit is a typical medium-low temperature hydrothermal fissure filling type deposit.Its ore bodies are strictly controlled by structural belts and F2,F3,F4 and F5 faults in the deposit are the main ore-hosting structures.In the profile,the main ore body shows a tendency of steepness in the upper part,slowness in the middle part and steepness in the lower part with an average thickness of 2.97 m and with an average grade of 63.99%.There are four types of ores,massive,cemented,band and chalcedony fluorite.Silicification,kaolinization,chloritization and sericitization are common in the surrounding rocks.From centre of ore-bearing structures toward outside country rocks,the alteration displays obvious zoning characteristics.Sm-Nd isotopic dating of fluorite yields an age of 120±17 Ma with initial 143Nd/144Nd ratio of 0.512031±0.000026 andεNd(t)=-8.8,similar to the SHRIMP zircon U-Pb dating age 112-125 Ma for Taishanmiao intrusion(initial 143Nd/144Nd ratio=0.511653-0.512506 andεNd(t)=-16.1 to-7.5).Ii is obvious that the mineralization took place in the late Yanshanian of early Cretaceous.Therefore,the ore-forming materials of fluorite deposit are similar to those of Taishanmiao intrusion and were originated from the crust.

关 键 词：萤石矿 地质特征 SM-ND同位素年龄 陈楼 豫西 

分 类 号：P597.3[天文地球—地球化学] P619.2[天文地球—地质学]