西藏沙让特大型钼矿的发现与瞬变电磁法探查  

Discovery and TEM detection for large-scale porphyry molybdenum deposit in Tibet

作　　者：薛国强[1] 秦克章[1] 李貅[2] 戚志鹏[2] 周楠楠[1] 

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院矿产资源研究重点实验室,北京100029 [2]长安大学地质工程与测绘学院,西安710054

出　　处：《地球物理学进展》2011年第3期954-960,共7页Progress in Geophysics

基　　金：国家自然科学基金项目(40772066);十一五科技支撑计划冈底斯成矿课题(2006BA01A04);青藏973斑岩铜矿课题(2002CB412605);中国科学院知识创新工程重要方向项目(KZCX2-YW-Q04-07)联合资助

摘　　要：近10年来,西藏冈底斯斑岩成矿带找矿取得重要研究成果,成为研究热点地区之一.西藏沙让地表为粘土化低温矿化蚀变、总体品位不够.穿插有小而富的脉状辉钼矿,规模有限,深部成矿状况不明.利用大回线源瞬变电磁法新技术进行工作,成功改装瞬变电磁接收装置;定义大回线源瞬变电磁晚期视电率计算公式;采用修正后的视电阻率计算公式进行数据处理,完成大深度瞬变电磁探测目的,划分出低电阻率异常,推测主矿体在地表200 m以下,矿体垂直延伸大于600m,异常区的面积总和为3.77 km^2,解释结果得到钻探验证,取得良好的地质效果.研究成果表明沙让钼矿为西藏首例独立的特大型斑岩型钼矿床,研究成果具有重要的区域找矿示范意义.During the last decade, many achievements of exploration to the Gangdese Metallogenic belt of Tibet have been reached, which became one of hot topics. The surface of Sha-rang area of Tibet is covered by low-temperature mineralization and alteration of clay, and the total ore grade is low. Although, an interlude of small and rich Mo mineralization has been discovered, the ore scale is limited, and the condition of deep ore is still unknown. Large-loop TEM, a new technology, was carried out in Sha-rang area in Tibet for deep target exploration. The TEM receiving configuration has been reformed. Large-loop Tern late-time resistivity formula has been defined. The revised formula has been employed to finish TEM field survey. After data processing, low resistance anomalies are discovered. The conclusion is that the main ore body is buried underground deeper than 200 m. The scale of ore body has a vertical extension more than 600 m, and total area of electromagnetic anomalies is 3.77 km2. The interpretation result agrees with the drill data, and good achievement has been reached. The result shows that it is the first special large-scale porphyry molybdenum deposit. This discovery has a great significance and guidance for regional research and prospecting.

关 键 词：瞬变电磁 大回线 西藏沙让 特大型钼矿 非零偏 

分 类 号：P631[天文地球—地质矿产勘探]