Experts note the slow but inevitable fragmentation of the African continent
A crack that appeared fifteen years ago in a region of Ethiopia serves as an important point of study for scientists on the movements of plate tectonics. According to them, the evolution of the fault will result in the detachment of part of the continent, with the consequence of the emergence of a new ocean.
In eastern Ethiopia, the Afar region is one of the warmest, driest areas in the world, temperatures can reach 55 degrees Celsius during the day and 35 degrees at night. It is also the junction point between three tectonic plates (Nubian, Somali, Arabic) that would be related to the brutal appearance in 2005 of a crack of more than 500 meters in a few days, while it should normally have formed in several centuries to such an extent .
Now, a crack over 56 km long can be seen. But in the depths of the gap, signs of separation part of the African continent have been detected, a phenomenon that attracts researchers around the world. This process, which will last between five and ten million years, will conclude with the formation of an ocean in the detachment zone, which will be significantly larger than the gap observed today.
Numerous hypotheses and estimates were made possible thanks to technological progress and, more specifically, to new measurements carried out by satellite, which also allowed researchers to closely monitor the volcanic activity linked to the movements of tectonic plates in the east. Africa.
In the Earth's crust, a dozen large plates constantly deform, colliding, separating or even overlapping. Afar is the only region in the world it is possible to study the formation of an ocean after significant tectonic movements, with the presence of three smaller plates ideal for research.
The detachment of one of them Africa (the Arabian plate) is responsible for the formation of the Gulf of Aden and the Red Sea, and the separation of the Somali plate and the Nubian plate. it is estimated to be responsible for the separation of the continent, which will start towards the Horn of Africa, along Kenya and Ethiopia.
GPS and satellite analyzes suggest to researchers that a powerful column of overheated rocks in the Earth's mantle is the cause of the activities that cause the crack. "With GPS measurements, you can measure movement rates of a few millimeters a year," said Ken Macdonald, a marine geophysicist and professor emeritus at the University of California. "As we get more and more measurements the GPS, we can get a much better idea of what's going on."
A comparison of the gap size with visitors. Credit: Anthony Philpotts
Cynthia Ebinger, a geophysicist at Tulane University, who has been studying the breach for many years to understand its rapid and violent onset, suggests that the large presence of magma must have caused extreme pressure. In fact, during the events of 2005, a volcano at the northern end of the rift erupted. However, magma never surfaced. It cooled below the crack and raised the soil at some point, causing the surface to rupture. But all experts agree that this is only the beginning of profound changes on the African continent.
"The Gulf of Aden and the Red Sea will invade the Afar region and the East African Rift Valley will become a new ocean, and this part of East Africa will become its small separate continent," said MacDonald.
Although the plates move away Africa at particularly slow and different speeds (about 2.5 cm per year for the Arab plate and 0.5 cm for Somalia and Nubia), they will eventually form a crest in a few million years. new ocean, in other words, a mountain range at the bottom of the sea. Clues observed by the researchers were demonstrated, with materials coming the depths of the earth's crust rising to form oceanic crusts.
"We can see that the oceanic crust is starting to form, because it is distinctly different the continental crust in its composition and density," said Christopher Moore, a doctoral student at the University of Leeds.