多道能谱测量在冀东花岗岩型稀有金属矿勘查中的应用

The application of multi-channel energy spectrum survey to the exploration of granite type rare metal deposits in eastern Hebei

冀东地区分布有众多燕山期花岗岩侵入体,具备良好的花岗岩型稀有金属矿成矿背景。为研究这些岩体的成矿前景,以该地区的汉儿庄花岗岩体为研究对象,开展多道能谱测量工作,分析了不同岩性放射性参数特征、放射性异常特征及与稀有金属成矿关系。研究表明,区内U、Th、总道计数异常明显,在二长花岗岩中的平均含量分别是全区背景值的9倍、8.5倍和3.9倍,异常场异常场展布特征与二长花岗岩的地表出露形态基本一致;结合岩石地球化学、人工重砂等成果,二长花岗岩全岩稀有金属矿化较好,岩石中含有大量褐钇铌矿、独居石等含U、Th、Hf矿物,这些矿物与Nb、Ta、Rb等稀有金属矿物存在共生关系。依据异常场分布及钍钾、钍铀、铀钾比值等参数的特征可直接圈出稀有金属矿化有利地段,指导探矿工程的布置。该方法的有效实施,为今后在花岗岩地区开展稀有金属矿勘查提供了一种便捷、高效、廉价的手段。

There are many Yanshanian granite intrusions in eastern Hebei,which constitute a good metallogenic background of granite-type rare metal deposits.In order to study the metallogenic prospects of these rock masses,the authors chose the Hanerzhuang granitic body in this area as the research object,and carried out the multi-channel energy spectrum survey to analyze the characteristics of radioactive parameters of different lithologies,the characteristics of radioactive anomalies and their relationship with rare metal mineralization.The results show that the average content of U,Th and total trace in the monzogranite is 9 times,8.5 times and 3.9 times the background value in the whole area,respectively.The distribution characteristics of the anomaly field are basically consistent with the surface outburst form of the monzogranite.Combined with the results of petrogeochemical study and artificial heavy sand,the authors hold that the monzogranite whole rock has a good mineralization of rare metals.The rocks contain a large number of U,Th and Hf minerals such as yttrium-brown niobium ore and monazite,and these minerals have a symbiotic relationship with Nb,Ta,Rb and other rare metal minerals.According to the distribution of anomaly field and the characteristics of thorium potassium,thorium uranium,uranium potassium ratio and other parameters,the favorable areas of rare metal mineralization can be directly delineated to guide the arrangement of prospecting engineering.The effective implementation of this method provides a convenient,efficient and cheap means for the exploration of rare metals in the granite area in the future.