莫桑比克上利戈尼亚地区航磁、航放异常特征及钽-铌矿找矿方向

Aeromagnetic and Aeroradiometric Characteristics in Alto Ligonha Area,Mozambique and Prospecting Direction of Ta-Nb deposits

为深化莫桑比克上利戈尼亚钽−铌稀有元素成矿带区域成矿规律研究,充分挖掘已有区域成果资料中隐含的找矿有利信息,笔者对所收集莫桑比克北部地区高精度航磁、航放测量网格数据进行转换处理,加强成矿弱信息提取,并在已有成果认识基础上开展区内地质构造的综合推断解释,分析总结区内的航磁、航放异常展布特征及与本区伟晶岩型钽−铌矿的空间对应关系,查明区内主要控矿构造−纳玛玛逆冲推覆带的分布范围和内部断裂构造展布特征。结合区内姆艾尼大型钽铌矿床航空物探综合异常特征,对全区进行类比找矿预测,圈定钽铌矿远景区5处。研究认为,该成矿带北东向延伸被F2断裂错断,南西向断距超过20 km,引起成矿有利区的整体北西转移,追索异常找矿意义重大。

In order to deepen the study on the metallogenic regularity of Ta–Nb rare element metallogenic belt and fully exploit the ore–prospecting favorable information contained in the aerial geophysical data in Alto Ligonha,Mozambique,the high–precision aeromagnetic and aeroradiometric survey grid data are collected in northern Mozambique and converted to enhance the extraction of weak metallogenic information.Based on the achievement recognition,the comprehensive inference and interpretation are carried out about the geological structure in the area.The distribution characteristics are analyzed and summarized of the aeromagnetic and aeroradiometric anomalies,and their spatial correspondences with pegmatite Ta–Nb ore in the area is discussed.A comparative study is carried out to find out the scope of Namama overthrust nappe belt,the main ore–control-ling structure in the area and the distribution characteristics of internal fault structures.Combined with the com-prehensive anomaly characteristics of the large Ta niobium deposit in the area,the analogy prospecting predic-tion was made for the whole area,and five Ta-Nb deposit prospects were delineated.It is believed that the northeastward extension of the metallogenic belt is faulted by F2 fault,and the southwestward fault distance is more than 20 km,which leads to the overall NW transfer of the favorable ore-forming area,and it is of great prospecting significance to pursue the anomaly.