Which geological process is primarily responsible for forming mountains?

Subduction is the geological process responsible for forming mountains, particularly in convergent plate boundary settings. When two tectonic plates collide, one plate is forced beneath the other in a process called subduction. This leads to the formation of mountain ranges, such as the Andes in South America, which were formed by the subduction of the Nazca Plate beneath the South American Plate.

During subduction, the descending plate can cause significant geological activity, including the uplift of mountain ranges and the creation of volcanic arcs. The intense pressure and heat at these plate boundaries can also lead to the metamorphosis of rocks, contributing to mountain building.

In contrast, weathering refers to the breaking down of rocks at the surface, erosion is the process of transporting soil and rock, and metamorphosis pertains to the transformation of existing rocks through heat and pressure. While weathering and erosion can shape mountain landscapes over time, they are not the primary processes responsible for the formation of mountains themselves. The critical role of plate tectonics and specifically subduction highlights why this process stands out in mountain formation.