The induced polarisation probe measures the charge separation or ‘chargeability’ in porous, water-saturated, mineralised rocks caused by the passage of a low-frequency alternating current. The main cause of induced polarisation is a current-induced electron-transfer reaction between ions of an electrolyte in contact with grains of semi-conducting metallic minerals.
Principle of Measurement:
The probe passes a controlled, alternating current through the formation between two outer electrodes and detects the variation with time of the resulting voltage measured between two inner electrodes after the device is removed. The integrated area under the voltage-time curve is a measure of chargeability.