等效介质理论激电模型频率相关系数的影响因素

Influence factors of frequency-dependent coefficient with GEMTIP model

本文基于广义等效介质理论激电(GEMTIP)模型,通过分析岩矿石中含有多种不同极化颗粒时,其复电阻率随频率的变化特征,进而分析频率相关系数的主要影响因素。结果表明,岩石中所含极化颗粒的形状、尺寸不完全相同时,随着它们变化范围的扩大,岩矿石复电阻率频谱曲线变得平缓、频率相关系数变小;岩矿石含有极化特性相差较大的多种极化颗粒时,其频率相关系数也变小;岩石内极化颗粒的极化特性相差不大时,频率相关系数主要反映岩石内矿物颗粒的形状和尺寸的变化。这些认识对于根据频率相关系数值的相对大小进行异常划分,并按结构区分引起激电异常的极化体具有重要的指导意义。

We use the generalized effective-medium theory of induced polarization(GEMTIP)model to analyze theoretically the frequency characteristics of the complex resistivity of rocks and ores filled with a variety of polarized grains,and then to study the main physical influence factors of frequency-dependent coefficient.The following understandings are obtained:A.When the shape and size of polarized particles are different,the spectral curve of complex resistivity becomes smooth and the frequency-dependent coefficient becomes smaller with the increase of the range of the polarized particles;B.When rocks and ores contain multi-type polarized grains with different polarization,the frequency-dependent coefficient also becomes smaller;C.When the polarization characteristics of polar-ized particles in rocks and ores are similar each other,the frequency-dependent coefficient mainly reflects the shape and size of the mineral particles.The understandings have important significances for the anomaly interpretation and the identification of polarized bodies based on the relative magnitude of the frequency-dependent coefficient.