Gossan or rust is formed at the surface due to the hydration of iron oxides in areas underlain by mineralized sulfides. Which technique is particularly suited for investigating these ore bodies?

• A. Landsat remote sensing
• B. Ground-penetrating radar
• C. Magnetic surveying
• D. Seismic reflection

Answer: (A)

The key idea is using a surface alteration signature to locate sulfide ore systems. Gossan forms a noticeable iron-oxide–rich cap at the ground surface above sulfide mineralization, and its iron oxides have distinctive spectral properties that Landsat satellites can detect across large areas. Landsat’s visible to shortwave infrared bands let you map oxidation zones and iron-oxide–bearing rocks, making it particularly useful for regional exploration and targeting where sulfide ore bodies lie beneath the surface. Other methods focus more on subsurface features or different rock properties (ground-penetrating radar for near-surface imaging, magnetic surveys for magnetic mineral anomalies, seismic reflection for deep structure), and don’t specifically exploit the surface iron-oxide signatures that indicate gossan mineralization.