The new ‘ocean’ that could be splitting Africa in two – 12/25/2023 – Science

A new ocean is emerging in Africa. It was believed that it was the result of a process that would take between 5 and 10 million years to occur. But new scientific discoveries indicate that this could happen sooner than expected.

“We cut time to something like 1 million years, maybe even half that,” says geoscientist Cynthia Ebinger to BBC Brasil. A researcher at Tulane University, in the United States, she has been studying the topic since the 1980s and has become a reference on the subject.

According to the Google Scholar website, Ebinger wrote, throughout his career, articles cited more than 16 thousand times by his professional peers and published in scientific journals as large as the English magazine Nature. In 2023, it signed 17 texts, most of which revolve around questions about the new ocean channel that is being opened in the Afar region, on the borders of three tectonic plates, the Arabian, the African (also called Nubian) and the Somalian .

The geoscientist has been paying attention to the subject since the late 1980s. In 1998, she published in Nature her article with the greatest impact in scientific circles, cited more than 900 times by her peers: “Cenozoic magmatism throughout East Africa resulting from impact of a single plume ” (“Cenozoic magmatism throughout East Africa resulting from the impact of a single hot spot”, in free translation into Portuguese).

In the study, he analyzed the action of magma on the Ethiopian plateau with a model that can be expanded to the action of volcanism throughout East Africa, which has been occurring for 45 million years.

It also identified that “the largest volumes of magma are in the Ethiopian highlands and East Africa, more than a thousand kilometers wide, crossed by the Red Sea, the Gulf of Aden and East African rift systems.”

Extent of the Red Sea

“There is a small volcano underground (in this region of Ethiopia) that is blocking a large body of salt water from passing through,” says Ebinger.

The three tectonic plates — the Somalian, to the east; the African (or Nubian), which is more extensive; and the Arabian, to the northeast—pressure a smaller plate, the Victoriana. As a rift in this plate encounter expands, part of the Somali plate may break away toward the Indian Ocean, making way for the new ocean.

“In fact, it won’t exactly be a new ocean, although we commonly call it that”, explains Ebinger.

“Visualize it as an expansion of the Red Sea.”

The three tectonic plates move at different rates.

Arabica moves 2.5 centimeters away from Africa per year. The other two, half a centimeter, each. This slow movement will divide the continent in half, cut by an immense mass of salt water coming from the Red Sea and the Gulf of Aden.

The main evidence for the theory comes from a colossal event that occurred in 2005. In September of that year, 420 earthquakes shook the ground in a desert area in Ethiopia. Volcanic activity sent ash into the air.

In the process, a 60-kilometer-long rift was opened in the Afar region, in one of the most inhospitable areas on the planet.

A study published in 2009, led by geophysicist Atalay Ayele, from Addis Ababa University, in Ethiopia, identified three sources of magma that caused the episode, in the Dabbahu-Gab’ho and Ado’Ale volcanic complexes, the largest of which part of the flow came from this second one.

According to the text published by Ayele in the scientific journal Geophysical Research Letters, this “volcanic-tectonic crisis” will “eventually form the morphology of an incipient oceanic rift.”

In responses to questions about the work sent by email by BBC Brazil, the geophysicist clarified: “Many rupture activities are already in action. The African plate is moving north and colliding with the Eurasian plate, forming mountains in the Alps”.

This entire geological process, however, will not occur in the next few centuries, nor in a few dozen millennia.

“The seismic map shows that an ocean is emerging, but it will take millions and millions of years,” Ayele summarized.

Maybe sooner than thought

Last month, Ayele and Ebinger were part of a group of nine scientists who published, in the journal Tectonophysics, a study that presented a 3D model of the geological actions occurring in the region.

Among the conclusions, they detected new and voluminous balsamic crusts forming in the region and that the layer under the Afar Depression would be less than 25 kilometers thick.

“These patterns suggest (…) a narrow zone of early seafloor spreading in the Afar depression,” the researchers wrote in the paper.

“Intense events can accelerate the process of crack opening and the passage of salt water”, theorizes geoscientist Cynthia Ebinger, in an interview with BBC Brasil, carried out via video call.

She now calculates an estimate of less than a million years to form the new ocean, from the waters of the Red Sea.

“But there could also be a large earthquake that accelerates it even further,” he says.

“The problem is that current science cannot accurately predict events like volcanic eruptions and earthquakes.”

Research into the great rift formed in the Ethiopian desert aims, in addition to answering questions about events that are only expected to occur in hundreds of thousands of years, to create seismic models capable of predicting future environmental catastrophes with greater accuracy.

“There are more immediate objectives, such as helping to improve the way we prepare to defend ourselves (from natural phenomena)”, concludes Ebinger.