The Gulf of Suezthe arm of the sea that extends in the northern part of Red Sea delimiting the Sinai peninsula, it progressively widens at the rate of approximately 0.5 mm per year. It is the result of the study by a team of Chinese, French and English researchers, published in the journal Geophysical Research Letters. Until now it was believed that the fracture hosting the Gulf of Suez, which originated from the separation of the African and Arabian plates, was now stable for 5 million years. New investigations have instead revealed that it is only expanding to a slower pace.
The study on the Gulf of Suez fracture
About 35 million years ago the Arabian plate and the African plate began to separate, moving in opposite directions with respect to each other, driven by the forces due to the rise of hot material from the Earth’s mantle. As a consequence, the crust has thinned and fractured. The fracture progressively widened until it entered into communication with the ocean waters: in this way the Red Sea. This sea bifurcates in its northern part into two branches: the Gulf of Suez and the Gulf of Aqabatwo fractures also generated by the movement of the plates, then filled by water.
Until now, researchers believed that the Gulf of Suez fracture, which opened approximately 28 million years agohad stopped widening approximately 5 million years ago with the change in the movement of the plates, preventing the gulf from evolving into a sea. Now new investigations have shown that this continental rift zone (i.e. a fracture zone that has developed within the continental lithosphere) it is still active: the gulf continues to widen, albeit at a slower pace, by approximately 0.5 mm per year. It was possible to find this out by examining hundreds of topographic profilesi.e. vertical sections of the terrain, along approximately 300 km of rift (the Gulf of Suez is 316 km long) and river profileswhose progress can demonstrate movements of the earth’s crust. The researchers also measured theheight of coral reefs which over time emerged from the sea until they reached 18.5 m above the gulf as a consequence of tectonic movements.
The importance of discovery
The discovery shows that the fractures generated in the continental lithosphere by the processes of separation between the plates they can slow down the pace with which they expand without necessarily being considered inactive. Until now it was defined as “failed“a process of continental rifting if this did not progress at a certain speed, leading to the opening first of a sea and then of an ocean, as is happening in the nearby African Rift Valley. Here the Somali and Nubian plates are moving away from each other at a speed of approximately 6-7 mm per year: According to forecasts, this process in about 210 million years will lead toopening of an ocean which will separate East Africa from the rest of the continent. The results of the study highlight the need for re-evaluate fractures considered inactive in the rest of the planet, verifying whether they are characterized by even minimal evolution. These characteristics could make areas like the Gulf of Suez more susceptible than expected to potentially destructive earthquakes.
