rifting

Rifting is a geological process where Earth's crust stretches and thins, leading to the formation of rift valleys. This occurs at divergent plate boundaries, where tectonic plates move apart. As the lithosphere stretches, normal faults develop, causing blocks of rock to slide downward, creating valleys.12

Continental rifting specifically happens when continents are pulled apart. Magma rises, causing uplift and stretching of the overlying crust. Fractures form, and as the continents separate, a rift valley emerges. This process can eventually lead to the creation of a new ocean basin as the continental crust thins and new oceanic crust forms along an ocean ridge. Examples include the East African Rift Valley and the rift valleys found along mid-ocean ridges.21