Which process most effectively forms tall mountain belts during continental collision?

• A. Subduction alone.
• B. Erosion of crust.
• C. Crust thickening and deformation creating folds and thrust faults.
• D. Ocean spreading.

Answer: (C)

Tall mountain belts form when continents collide and the crust is continuously squeezed. This compression shortens and thickens the crust, causing rocks to fold and stack along thrust faults. As the crust thickens, isostatic forces push upward, lifting the surface to create tall mountain ranges. Erosion can later wear them down, but the initial height comes from crustal thickening and deformation.

Subduction alone doesn’t produce these lofty continental ranges because continental crust is buoyant and resists sinking deep; the dominant process here is the compression that thickens and deforms the crust. Ocean spreading builds new crust at oceanic ridges, not tall continental mountains either.