Scientists find clues that a new tectonic plate boundary is forming

Sub-Saharan Africa may break up within a few million years, and scientists believe they may be witnessing the early stages of this geological process.

The split will occur along the Kafue Rift, part of an approximately 1,500-mile-long (2,500 kilometers) rift line stretching from Tanzania to Namibia. A rift is a crack in the Earth’s crust that distorts the surface and can cause land subduction and earthquakes. There are thousands of fissures around the world, and although the majority are inactive or dead, they can occasionally reactivate.

Geologists thought the Kafue Rift was long dead. But some experts now say it has shown signs of activity in the last few decades. Growing evidence raises suspicions that this feature could develop into a new continental rift and eventually become a new boundary between tectonic plates, creating a brand new sea in the process.

Pre studies We have collected these tips. Earthquakes too weak to be felt by humans but strong enough to be detected by instruments, increased underground temperature, and small changes in ground level detected by satellites indicate that the region may be tectonically active.

Now, a new study published Monday in the journal Frontiers in Earth Science It goes one step further. “We have the first geochemical data from this region,” said Rūta Karolytė, who conducted the research as a postdoctoral research fellow at the University of Oxford in England. “This is quite a different set of evidence that really strengthens the idea that there is rift activity in the region.”

Studying a new continental rift could help answer one of tectonics’ most fundamental questions.

“How does a new plate boundary begin? Mature plate boundaries are easy to recognize. The early stages are much more subtle,” said Estella Atekwana, a distinguished professor of Earth and planetary sciences at the University of California, Berkeley, who was not involved in the research.

“If the Kafue Rift is part of a newborn plate boundary, this gives us a rare opportunity to study the birth of a plate boundary before volcanism, large earthquakes and large surface deformations affect the original conditions.”

Clues to a new tectonic plate

To gather evidence, Karolytė and her colleagues collected samples from naturally occurring hot springs and geothermal wells on the suspected rift in Zambia. “There is hot water bubbling up to the surface, and we sampled the gas coming out of that,” said Karolytė, who is now chief product scientist at Snowfox Discovery, a UK-based natural hydrogen exploration company.

The researchers were mainly looking at the ratio between two types of helium (helium-3 and helium-4). The team looked for any signs that might suggest a connection between the springs and the wells. with the Earth’s mantlehundreds of miles thick layer sandwiched between the crust and the core. Karolytė added: “We found more helium-3 in the crust than you would normally find, which is usually a sign of mantle fluids rising to water.”

The result is only preliminary because the samples came from only six sites in a highly concentrated region. But researchers also sampled two hot springs about 60 miles (95 kilometers) from the suspected rift and found no similar increase in helium-3.

Because material from the mantle can reach the surface as tectonic plates begin to flex and separate, the study team believes this new geochemical data may be an early signal indicating the formation of a new plate boundary.

an economic benefit

tectonic plates They are huge slices of solid rock that range in size from a few hundred to thousands of miles and are about 120 miles (190 kilometers) thick. Since these plates developed early in Earth’s history, they have been sliding across the mantle at a speed comparable to the growth rate of fingernails. About 200 million years ago, shifting plates began pulling a world apart. The giant landmass called Pangea to today’s continents. The plates are still energeticand this movement drives geological processes such as earthquakes and the formation of volcanoes.

Boundaries between plates are often under the oceans and they can slide over each other, collide with each other, or pull apart. The borders are also areas where most earthquakes and volcanic activity occur.

An active, developing rift may, but does not necessarily, develop into a tectonic plate boundary. “These rifts can start and stop frequently, or they can spread a little and stop again. It’s hard to predict what will happen,” Karolytė said.

There is already a well-developed rift in Africa that is tens of millions of years old. The East African Rift has many volcanoes and is seismically active. However, it would take a long time for the new crack to develop in this way and turn into a plate boundary. “At the fastest, it could happen in a few million years. At the slowest, it could take 10 or 20 million years,” said study co-author Mike Daly, a visiting professor of Earth sciences at the University of Oxford.

“The southern part of Africa will break away, but before that you’ll start to see a lot more earthquakes and you’ll start to see some volcanic activity with lava flowing out. Deep fissures will start to form and the water will start to stagnate in it, so when you get to East Africa today you’ll get lakes and eventually the sea,” he added.

However, in the much nearer term, Zambia can benefit economically by tapping into energy; Geothermal power plants are emerging in the region. This landlocked country can even harvest helium, which is in high demand and has various applications in the medical and technology industry.

To confirm the findings, researchers are collecting more gas from a wider geographic area along the suspected rift and working on a new study with broader implications.

Answering basic questions

Folarin Kolawole, an assistant professor in the department of Earth and environmental sciences at Columbia University in New York who was not involved in the research, thinks the findings are new and exciting because they provide “strong confirmation” of the direct upward flow of fluids from the mantle to the surface through newly formed rift zones.

“The key importance of a new plate boundary in southwest Africa is that we now have an established path for the continent to separate from East Africa through Botswana and Namibia to the Atlantic Ocean,” he added in an email.

The number of samples is limited, but the results are still significant, according to UC Davis’ Atekwana. “They provide strong geochemical evidence that the Kafue Rift is active at depth even if the magma has not reached the surface,” he wrote in an email.

But Atekwana added that more evidence is needed across the entire proposed boundary to determine whether the mantle’s helium signal is continuous or only local. “This is not the final word but an important line of evidence. It supports the early-stage rifting hypothesis, but confirmation of a new plate boundary requires a full plate boundary scale test,” he said.

“This does not mean that Africa will break apart tomorrow; these processes occur over millions of years. But scientifically, this would be like catching a plate boundary by the act of being born.”

Sign up CNN’s Wonder Theory science newsletter. Explore the universe with news about fascinating discoveries, scientific breakthroughs and more.

For more CNN news and newsletters, create an account at: CNN.com