The wilson cycle: he suggested that thorughout the history of the earth there have been two cyclic processes of rifting and reuniting of supercontinents. A clear example of continental rifting is found in the rift valley in east africa. 1. A dome forms: the heat under the continent causes the crust to expand and lift up. 2. Continental rift stage: large fractures appear which make the litosphere thinner and lead to the formation of a continental rift. 3.Narrow sea stage: the continent has completely split and separated. 4. Maturing ocean stage: the divergence continues and the fomation of oceanic litosphere due to sea-floor spreading increases. 5.Shrinking ocean stage: the ocean begins to coles because of subduction on its boundaries. 6. Convergence stage: the ocean has almost closed. The continents converge with marine sediments on their edges. 7.Continental colission satge: The boundaries of both continents and the sediment trapped between them are deformed. 8.Final stage: the continental masses are joined together and a mountain range is formed from the collision of the continents. Eventually the plate boundary will become inactive.