On the vast land of Africa, there is a huge word "Zhi". It is the largest continental rift valley system on the earth-the Great Rift Valley of East Africa, with a total length of 6500 kilometers. It runs through the African continent from north to south and branches into east and west. The eastern Rift Valley is the main trunk, extending from northern Africa through Ethiopia and southward to Kenya, including a long and narrow rift valley and majestic plateau; the western branch is slightly smaller and adjoins a series of Africa's highest peaks and deepest lakes.
The Great Rift Valley of East Africa is ultimately a masterpiece of plate tectonics. Canadian geophysicist and geologist Wilson put forward a hypothesis to describe the movement pattern of the earth's plates: the continental lithosphere cracked up under mantle convection to form a rift, which was the beginning of the primitive ocean; as the rift continued to expand, mid-ocean ridges were gradually formed, and the rift expanded to form a real ocean; the oceanic plate subducted to the continental lithosphere on both sides, or collisions between continental plates occurred, resulting in orogenic belts, leading to the proliferation and splicing of continents. The Great Rift Valley of East Africa is a young rift system, where it can be thought that the primitive ocean or embryonic form of the ocean is gradually expanding and forming.
The mechanism that formed the Great Rift Valley in East Africa is very complex, and there has been no unified answer among scientists for a long time. Most geologists believe that in the asthenosphere deep underground, the mantle upsurges, stretching and thinning the originally unified African plate, and cracks appear in some areas. The plates on both sides of the fault continue to move, either horizontally expanding or vertically. Uplowing, as a result, smaller faults continue to develop and eventually form a huge rift system on a continental scale that reaches the upper mantle. Mantle upwelling also drives the continuous uplift of the crust in the Great Rift Valley, forming the huge East African Plateau. The upwelling mantle also provides part of the source of magma upward, resulting in a lot of volcanic activity in Africa.
Some geologists believe that there once existed a huge mantle plume under the Africa-Arabian Peninsula plate. The heating and impact of the mantle plume would arch the fragile lithosphere in the upper layer and eventually rupture it. Under ideal conditions, the arched lithosphere forms a large "triple cusp". The three fault zones generated from the rupture point are at an angle of 120° to each other. These fault zones will eventually develop into a three-pronged rift system. The Great Rift Valley of East Africa is only one branch of this large three-pronged Rift Valley. The other two branches are the Red Sea and the Gulf of Aden. As time progresses, the trident rift system develops wider and wider, and will eventually tear the complete continental plate into several small plates. The widening rift may evolve into a new ocean.