不同类型低阻异常航电时间常数的特征分析  

The characteristics of time constant of different conductive anomalies from airborne TEM data

作　　者：骆燕[1,2] 江民忠[1,2] 宁媛丽[1,2] 彭莉红[1,2] 朱琳[1,2] LUO Yan JIANG Min-Zhong NING Yuan-Li PENG Li-Hong ZHU Lin(Airborne Survey and Remote Sensing Center of Nuclear Industry, Shijiazhuang 050002, China Key Laboratory for Geophysical Exploration Technol- ogy Center of Uranium Resource CNNC, Shijiazhuang 050002, China)

机构地区：[1]核工业航测遥感中心,河北石家庄050002 [2]中核集团铀资源地球物理勘查技术中心重点实验室,河北石家庄050002

出　　处：《物探与化探》2016年第5期991-997,共7页Geophysical and Geochemical Exploration

基　　金：内蒙古自治区地质勘查基金管理中心地质勘查项目(2014-01-KY04);新疆维吾尔自治区地质勘查基金项目管理中心地质勘查项目(T14-1-LQ29)

摘　　要：时间域航空电磁系统工作原理是机载发射线圈向地下发射脉冲电磁波,接收线圈观测断电后来自地下低阻体的二次感应电磁场,通过对观测数据进行处理解释达到探测地下低阻体的目的。结合近年来从事时间域航空电磁法探矿数据和资料解释的实践,分别对电力干扰、表层强低阻体、表层弱低阻体和地下低阻体航电异常响应的时间常数τ的特征进行了综合分析,总结出以下规律:电力干扰在τ图上一般显示为不连续的线性异常,电磁响应呈跳跃状的无规律衰减;低阻异常在τ图上一般显示为高值区,电磁响应呈指数衰减,导电性越好规模越大的低阻体衰减越慢。The principle of airborne time domain electromagnetic system is that Tx coil transmits electromagnetic pulse into ground,and Rx coil receives the induced secondary EM fields from conductive bodies in the earth. The secondary fields generated by induced current of conductive bodies contain geological information. Data processing and interpretation help to achieve prospecting for multi-metal mineral resources. The authors analyzed features of time constant reflection to power line interference under the conditions of near surface conductive bodies,near surface weak conductive bodies,and deep conductive bodies respectively and summarized the characteristics of time constant of different geological bodies based on knowledge of known mineral formation and two years＇ experience in airborne EM surveys. Some conclusions have been reached： the power line interference generally shows a discontinuous linear anomaly in τ map and electromagnetic response is jumping like irregular attenuation; low resistivity anomaly generally shows high value area in τ map and the electromagnetic response decays exponentially. The low resistance body decays more slowly when the conduction is better and the body is bigger.

关 键 词：低阻异常 时间常数 时间域航空电磁法 电磁响应 感应磁场 

分 类 号：P631[天文地球—地质矿产勘探]