Why the continent’s split is so exciting for science

Time and time again, Hollywood has embraced an impending apocalypse, as films like “2012” projected the fictional end of the world onto the big screen.

Fortunately, the scientific logic of many of these films has been, to say the least, creative. The planet’s crust didn’t suddenly shift 14 years ago and sweep most of us into a series of earthquakes, eruptions and megatsunamis.

And yet, by the time you get to the end of this sentence, Africa will be one step closer to division. The remote Afar region of northern Ethiopia lies at the center of a Y-shaped rift system, along which the continent separates to form a new ocean.

Leave your canned goods on the shelf and put down the apocalypse shovel, you don’t need to head straight to your apocalypse bunker. It’s less about the movie “The Day After Tomorrow” and more about the day after a few million years.

“It can often get lost in communication,” Emma Watts, part of a research team that embarked on a large research project to study the region, told CNN.

“People see that and say, ‘Oh no, it’s falling apart!’ » No, it’s very, very slow… I could say it until I’m blue in the face, but people still go for the clickbait title. Just grin and bear it.

A hellish paradise

One of the driest and hottest regions on Earth, where summer temperatures exceed 50 degrees Celsius (122 Fahrenheit), the aptly named Afar region is about as isolated and hostile as it gets. In its Danakil depression lies the Erta Ale volcano, home to a decades-old lava lake and locally nicknamed “the gate to hell”.

But for scientists, it’s paradise.

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Indeed, it lies at the junction of three tectonic plates – the Great Ethiopian Rift, the Gulf of Aden Rift and the Red Sea Rift – which are gradually moving apart in a process known as continental rifting. As the plates diverge, the mantle beneath rises and, if observed all the way, melts to form a new ocean basin.

It’s far from the only triple-junction rift system on the planet and continental rifting has been happening for billions of years, but Afar is invaluable to researchers because the process is literally happening beneath their feet. By the time rifting occurs, in the late stage when the ocean floor has almost formed, it is usually hidden far beneath the sea.

“Afar is a beautiful place because it (the new ocean floor) is not completely submerged yet,” Watts explained. “It gives us a window into a process we don’t normally see.”

Fascinated by volcanoes since hearing about the eruption of Mount St. Helens in Washington state in 1980 while she was in college, Watts jumped at the chance to join a team studying the region while pursuing her doctorate in volcanology at the University of Southampton in southern England.

Their research, published last June, revealed the presence of a single asymmetric plume rising from the depths of Afar. Geologists had already theorized its existence, but the new findings went further by showing that the plume pulsated in a pattern similar to a “heartbeat”, although not necessarily at a constant rate.

This pattern propagates differently at each of the three faults depending on tectonic conditions, Watts explained, evidence that the plume is dynamic and reacting to the plate above it, not static.

“Before this study, we thought the plume was simple: it emerged, it was a single composition,” she said.

“But we actually think there could be heterogeneities (varied characteristics) within the plume, whether it’s the amount of melt or its composition. That also interacts with that division rate, causing these variations.”

It’s time to learn

This fracture rate, Watts points out, is extremely slow.

The Red Sea and Gulf of Aden rifts are moving at a rate of about 15 millimeters per year, half the speed at which fingernails grow, while the main Ethiopian rift is moving even slower, at about 5 millimeters each year.

At this rate, it will be millions of years before a new ocean forms, and it’s not guaranteed. The process of continental division can fail, like the Mid-Continental Rift which would have torn North America apart around the Great Lakes.

This is music to the ears of scientists, who continue to make new discoveries in the region. The separation of the plates exposes older layers of sediment, shedding light on nearly 5 million years of evolution.

A series of preserved fossils have been discovered in Afar, with research published in the journal Nature in January revealing the discovery of a 2.6 million-year-old fossil of an extinct human relative.

The remains of Paranthropus, nicknamed the Nutcracker because of its pronounced chewing muscles, were typically found in the southern and eastern regions of the continent, such as Kenya. Its existence approximately 1,000 kilometers (621 miles) north of any other record suggests that the species was more adaptable and widespread than previously thought.

“It (Paranthropus) was thought to have never dispersed this far north, either due to ecological factors or competition with other species in the area,” London Natural History Museum paleontologist Dr. Fred Spoor, a member of the research team, said in a press release.

“The new discovery now suggests the opposite and the supposed absence was the result of an incomplete fossil record.”

Last August, fossilized teeth of two other types of hominids dating from 2.6 to 2.8 million years ago were discovered in the Afar Depression, shedding new light on the coexistence of our human ancestors.

The possibilities for discovery are almost endless, with Watts hoping to enrich the volcanic understanding of the region following the eruption of the long-dormant Hayli Gubbi volcano in Afar in November.

The ensuing ash cloud was so intense that it choked local grasslands and affected air travel to India.

“I think often with the risk in the region, we don’t know much because the eruptions haven’t been seen as frequently,” Watts said. “I would like to continue to make sure we understand these volcanoes and help advance the science of what is happening with the faults and the dangers we face.”

“Like all science, you take a step forward and there is still a huge way to go,” she added.

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