New Study Shows That a Gulf Thought Long 'Dead' Is Still Alive— and Quietly Pulling Continents Apart

Gulf of Suez. The story of this L-shaped piece of land began around 28 million years ago when a sinistral twisting of the Arabian plate triggered the divorce between the African and Asian plates. The two plates started pulling apart in a dramatic tectonic rifting dance, which ultimately birthed the Gulf of Suez. The more the rift kept widening in this tectonic ballet, the more magma burst from the crust and welled up along the edges, sandwiching an ocean that eventually filled up the gulf. Then, 5 million years ago, the gulf was declared a historic and classic textbook failure. The rift had stopped widening, and the gulf was supposedly “dead.” Or maybe not. In a research published in Geophysical Research Letters, researchers documented the entire mystery, revealing that the rifting just slowed down, never stopped.

The Gulf of Suez is regarded as an “archetypal failure” in Egypt. While millions of years ago, the rifting initiated with vigorous downwarping and normal faulting, eventually, it appeared to quieten down. For the past few decades, geologists were made to believe that the Gulf had died and gone static. Until this study, the gulf was just an ordinary stretch of land spanning 195 miles long and 20 miles wide, running from the northern mouth of the Red Sea to the western side of the Sinai Peninsula, flanked by the Mediterranean Sea and guarding the southern entrance of the Suez Canal. But as it turned out, the geometrical transformation had never stopped.

After this study, researchers think, and wholeheartedly believe, that this gulf, which partially divides Africa and Asia, may still be widening. The discovery was made only recently, but when they looked back in time, they noticed that little hints and clues had been scattered throughout for them to decipher. The fact that the Gulf is wholly alive had been hiding in plain sight all the time. Coral reef terraces had been lifting above sea level, small earthquakes had been shaking the surrounding landmasses, faults had been subtly raising certain portions of the ground, and little coastal mountains named "gebels" had been rising from the faults. Clues were everywhere, only eclipsed by the numerous geological processes and geometrical shifts.

The clues became illuminated when researchers studied a 186-mile fragment of the rift zone and noticed a disconnect between the age-old rifting story and the ongoing activities in the Gulf. The topography and the paths of rivers cutting through rock revealed unusual profiles that couldn’t be explained by erosion alone, which caused them to conclude that they must come from some sort of tectonic movement. Together with the elevation of the coral reefs, the mosaic of clues indicated clearly that the two plates are still pulling apart by about 0.02 inches a year.

The pulling apart is potentially driven by changes in some tectonic plates, far-field stresses, low-magnitude seismic activity, crustal movements, or young offshore faulting. Furthermore, earthquake tomography images portrayed potential “crustal necking structure in the southern rift that would favor lithospheric weakening,” as they described in the research. Whatever the complete story, the discovery challenges the “conventional views of post-rift tectonic quiescence.”

In conversation with Live Science, lead study author and geoscientist David Fernandez Blanco said, “We believe our work fundamentally changes how we think about rift evolution,” adding that the discovery unveils a “middle path” by which rifts can decelerate without truly failing. Concluding the research, Blanco mentioned that an “abandoned rift” doesn’t necessarily imply that it is a failure. It just means that the plate boundaries are changing, and this change doesn’t shut down rifting. The only thing that happens is, the plate tectonic dynamics become more complex and difficult to decode than previously possible.

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