Question

Which of the following can indicate the presence of significant sub-surface iron mineralization?

• A. Free air gravity anomaly
• B. Bouguer gravity anomaly
• C. Magnetic anomaly
• D. Electrical resistivity measurements

Hint:

Magnetic surveys and gravity anomalies are key methods for detecting iron ore deposits due to the physical properties of iron-rich minerals.

Answer 1

The Correct Option is B, C

Step 1: Understanding Geophysical Methods for Iron Mineralization
Iron mineralization is often associated with magnetic anomalies due to the magnetic properties of iron ores, as well as with gravity anomalies:

Bouguer gravity anomaly: This anomaly accounts for variations in the Earth's gravitational field due to changes in the density of subsurface materials, including iron mineralization.
Magnetic anomaly: This anomaly arises due to variations in the Earth's magnetic field caused by the presence of magnetic minerals such as iron ore. Magnetic anomalies are commonly used to detect the presence of significant subsurface iron mineralization.
Free air gravity anomaly: This anomaly is related to the Earth's gravity field at a specific altitude and is not specifically indicative of iron mineralization.
Electrical resistivity measurements: These are used to detect the presence of water or conductive materials but are not typically used to detect iron mineralization directly.

Step 2: Conclusion
Option (B) and (C) are correct because both Bouguer gravity anomalies and magnetic anomalies are commonly used to detect subsurface iron mineralization.