Induced-Polarisation
Probe
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 drive is removed. The integrated area under the
voltage-time curve is a measure of chargeability.
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