Induced polarization (IP) phenomena were first observed in 1912 by Conrad Schlumberger, where electrically conductive materials exhibited a delayed voltage response after an applied current was switched off. IP parameters respond to disseminated mineral grains and chargeability is measured by sending a pulsating current to create ion exchange between mineral grains and pore fluids. When the current stops, the voltage drops and dissipates gradually over time. IP measurements use similar equipment to resistivity surveys and the two techniques are usually conducted together.

1. Induced Polarization (IP), background
• IP phenomena have been noted by Conrad Schlumberger in
1912, i.e. earth materials discharge after applied current is
switched off
→ capacitance effect or chargeability
• Electrically conductive materials exhibit delayed voltage
response or over-voltage effect
• IP parameters response to disseminated mineral grains (rather
than massive ore)
• Equipment used in IP measurement is similar to (but much
more elaborate than) that employed in resistivity work
→ IP and resistivity surveys are usually conducted at the
same time

2. Induced Polarization (IP), origin
• Exact cause of IP phenomena are still unclear, but two main
mechanisms of electrochemical process are reasonably
understood
→ grain or electrode polarization
→ membrane polarization
• Chargeability is measured by sending a pulsating current to the
ground that creates an exchange of ions between mineral
grains and surrounding pore fluids. When the current is
stopped, the voltage drops and then gradually dissipates.
• Chargeability is related to the ratio of the overvoltage to the
applied voltage, and the lapse time it takes the ground to
“uncharge” after the transmitter is cut off.

3. Induced Polarization (IP)
grain or electrode polarization

4. Time Domain IP

5. Frequency Domain IP

6. Frequency Domain IP

7. resistivity
and
induced polarization
in mineral
exploration

8. resistivity
and
induced polarization
in mineral exploration

9. resistivity
and
induced polarization
in mineral
exploration

10. resistivity
and
induced polarization
in mineral exploration

11. 3-D
resistivity
3-D
induced
polarization

12. Induced Polarization
in groundwater study
(modelling)