阿尔泰成矿带中蒙边界地区稀有元素铌和钽区域地球化学特征
Regional Geochemistry of Niobium and Tantalum Across the Boundary of China and Mongolia in the Altay Metallogenic Belt

摘要： 铌和钽是高科技不可或缺的稀有金属材料，阿尔泰是重要的稀有金属成矿带，开展阿尔泰成矿带铌和钽资源远景优选至关重要。收集了中蒙边界1∶100万铌和钽地球化学数据，探讨其在不同构造单元内的背景值及区域地球化学异常特征。全区铌、钽元素中位值和平均值分别是1380×10-6和1493×10-6、111×10-6和131×10-6，中国境内铌元素中位值(1219×10-6)和平均值(1331×10-6)分别低于蒙古国境内铌元素中位值(1490×10-6)和平均值(1639×10-6)；相应地，中国境内钽元素中位值(102×10-6)和平均值(120×10-6)也分别低于蒙古国境内钽元素中位值(120×10-6)和平均值(141×10-6)；对于划分的构造单元而言，戈壁阿尔泰弧盆系、阿尔泰南缘弧盆系和阿尔泰构造带铌、钽元素的中位值和平均值分别高于全区中位值和平均值，是铌、钽元素的富集区，且产出大量稀有金属矿床；根据85%累积频率，圈定出13个铌异常区并优选出7个铌地球化学省，同时圈定出13个钽异常区并优选出10个钽地球化学省，根据铌、钽组合异常图为该区寻找稀有金属矿床提供了重要选区。研究填补了阿尔泰成矿带中蒙边界地区铌、钽元素地球化学分布的空白，同时为研究区稀有金属矿床对比提供基础数据。
Abstract: Niobium and tantalum are indispensable rare metal materials for high technology, and Altay is an important rare metal metallogenic belt, so it is crucial to carry out the potential prospect areas of niobium and tantalum resources in this area. This paper discussed the background values of niobium and tantalum in different tectonic belts and the regional geochemical anomalies based on the 1∶1,000,000 geochemical data across the boundary of China and Mongolia in the Altay metallogenic belt. The median and average values of niobium in the whole area are 1380×10-6 and 1493×10-6, and the two values in China side (1219×10-6 and 1331×10-6) are lower than those in Mongolia side (1490×10-6 and 1639×10-6). The median and average values of tantalum in the whole area are 111×10-6 and 131×10-6, and the two values in China side (102×10-6 and 120×10-6) are also lower than those in Mongolia side (120×10-6 and 141×10-6). The median and average values of the arc basin system in the Gobi Altay, the arc basin system in the southern margin of Altay and the Altay tectonic belt are higher than other tectonic belts, showing that niobium and tantalum are enriched in those area. The total of 13 niobium and 13 tantalum geochemical anomalies have been delineated respectively based on the 85% cumulative percentage, and 7 niobium and 10 tantalum geochemical provinces have been selected. The work fills the gap in the niobium and tantalum geochemical distribution and provides important data for the comparison of deposits in the study area