What can occur at a collisional boundary?

At a collisional boundary, the most significant geological activity that occurs is the crumpling and folding of land masses. This type of boundary is characterized by the collision of two tectonic plates, which often leads to intense pressure and deformation of the Earth's crust. As the plates push against each other, they can create mountain ranges, cause thickening of the crust, and result in the formation of complex geological structures such as folds and fault lines.

The process often involves the convergence of continental plates, which do not subduct as readily as oceanic plates due to their lower density. This results in the uplifting and crumpling of the crust, forming features like mountains and plateaus. This contrasts with other processes found at different types of boundaries, such as the formation of new oceanic crust at divergent boundaries or volcanic activity that can occur at subduction zones, but is not a primary feature of collisional boundaries. Thus, the correct focus on crumpling and folding reflects the unique geological dynamics present at collisional boundaries.