Geophysical Journal | 2005 volume 27 5

The role of mineral composition in the change of electrical properties of crystalline rocks

© Shepel S.I., Novik N.I.

An investigation of the influence of mineralogical composition of series of rocks on their specific electrical resistance (r) wich is measured by direct and alternating current (1 kHz) also on dielectrical permeability (e) on the frequency 1 and 700 kHz has been made. The studied complexes are presented by the rocks of ultra-basic composition, alkaline-subalkaline, and metamorphic (gneisses, shales, migmatites). The increase of total content of quartz and feldspar causes the increase of r, and decrease of e of dry and air-dried samples of rocks. The increased number of lowohm ore minerals bring to decrease of specific electrical resistance and increasing dielectrical permeability of individual groups of rocks and also all of them. The increasing of amorphous glass in basalt composition decreases their r and increases their e. Equations of linear regressions between sums of highohmed, lowohmed minerals with logariphms of electrical resistance, dielectrical permeability for some types of rocks and also for totality of magmatic formations were calculated. The received coefficients of correlation show that in the last case more close connentions are fixed. The influence of mineral composition on the electrical characteristics of metamorphic rocks are mostly weak which is connected with the raised heterogeneity of their texture with the presence of noticable foliation and slaty cleavage.

<<back |