Question

There are indications of presence of a massive tabular multimetal sulfide ore body at a shallow depth from the surface. Which of the following would be the most efficient geophysical method to confirm the presence of the ore body?

• A. Resistivity sounding
• B. Ground geomagnetic survey
• C. Self-potential method of geophysical prospecting
• D. Ground gravity survey

Hint:

The ground gravity survey is particularly effective for detecting dense ore bodies such as massive sulfides, which contrast well with their surroundings.

Answer 1

The Correct Option is C

To detect a massive tabular multimetal sulfide ore body at shallow depth, it is important to use a geophysical method that can effectively distinguish between the ore body and the surrounding rock. The best method for detecting sulfide ore bodies is the ground gravity survey.
- Option (A): Resistivity sounding measures the resistivity of the ground but is less effective for sulfide ores, as they may not always show significant resistivity contrasts compared to surrounding rocks.
- Option (B): Ground geomagnetic survey detects magnetic anomalies, but sulfide ore bodies do not always produce strong magnetic anomalies unless they are particularly magnetite-rich.
- Option (C): Self-potential method of geophysical prospecting measures natural electric potentials but is not as widely effective for detecting massive sulfide ore bodies compared to other methods.
- Option (D): Ground gravity survey measures density contrasts in the subsurface. Sulfide ore bodies are typically denser than surrounding rock, making gravity surveys a very effective tool for detecting them.
Step 2: Conclusion.
The best method for detecting a sulfide ore body at shallow depth is a ground gravity survey, which provides the most direct information based on density differences.