摘要
本文通过对长江中下游地区侵入岩长石铅、矿石硫化物铅同位素组成对比研究。说明长江中下游铜铁多金属成矿带可划分为东区（宁芜以东宁镇和苏锡地区）和西区（宁芜及其以西至鄂东南地区）．东、西两区的侵入岩长石铅和矿石硫化物铅同位素组成具有明显差异，在207Pb／204Pb-206Pb／204Pb图上它们的投影点明显地分为两个分布区。据铅同位素资料计算，长江中下游地壳形成时间主要是26－38亿年；据亮幔混合铅模式计算的μMix值表明，本区侵入岩和接确交代型矿石铅为壳幔混合源，以地幔源为主，前者幔源铅约占63-74％．后者幔源铅约占51－74％，层状含铜黄铁矿型矿体矿石铅主要来自上地壳。
The research of Pb-isotope of the feldspar in intrusive rock, as well as that of the sulfidein ores reveals that there are two different areas in the Middle-Lower Yangtze Cu-Fe multi-metalmetallogenic belt, one is the east district including Nanjing-Zhenjiang and Suzhou-Wuxiareas, the other is the west district including the areas from Nanjing-Wuhu to Daye-Yangxin.lt is evident that the composition of Pb-isotope of the feldspar in the intrusive rocks and thesulfide in ores is different between the two districts. On the plot of 207Pb/204Pb-206Pb/204Pb,two distinct fields are clealy shown. According to the Pb-isotope composition, the age of thecrust in Middle-Lower Yangtze area is about 2600-3800Ma. The calculating values of μMix. aC-cording to the mantle-crust mixture model of lead demonstrate that the lead in intrusive rocksand in skarn ores were derived from the mantle-crust mixture, in which the mantle-derived ispredominent' The mantIe-derived lead in intrusive rocks is about 63-74%, while that in theskarn ores is about 51-74%. The lead in the stratiform cupriferous pyrite ore mainly derivedfrom the upper crust.
出处
《火山地质与矿产》
1995年第2期67-77,共11页
Volcanology & Mineral Resources
基金
国家攀登项目!30-12
国家自然科学基金!4790272104
关键词
铜矿床
铁矿床
多金属矿床
铅同位素
Pb-isotope composition,the mantle-crust mixture model of lead, Middle-Lower Yangtze area
