Low‐frequency permittivities of skarns and associated rocks

Abstract

The lossy dielectric properties of dry heterogeneous skarns and associated rocks vary significantly when the real (ε′) and quadrature (ε″) permittivity responses are measured between 1 Hz and 160 kHz. Ores containing iron oxides and/or sulfides show very large permittivity values and high loss tangents with some dc conductivity. Unmineralized skarns manifest large ε′ and moderate ε″ values. Country rock, limestones, and granitoids show relatively low permittivities. The dielectric responses are ascribed generally to Maxwell‐Wagner mechanisms. No clear, convincing correlations are apparent between petrological characteristics and dielectric properties, but as iron and titanium content increases, so does the imaginary permittivity. Both real and imaginary permittivities are strongly influenced by density, and this effect must be removed before the effects of mineralogy can be observed.