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Earth’s continents may look fixed on a globe, but they’ve been drifting, splitting and reforming over billions of years – and they still are. Our new study reveals fresh evidence of rhythmic pulses of molten rock rising beneath east Africa, reshaping our understanding of how continents break apart.

Our findings could help scientists understand more about volcanic activity and earthquakes.

There are around 1,300 active volcanoes on the Earth’s surface . Active volcanoes are those thought to have had an eruption over the last 12,000 years or so. Of these volcanoes, over 90 lie on the East African Rift Valley – the seam along which Africa is splitting apart. This weak seam of crust may even allow a new ocean to form over the next few million years.

Although ocean formation is happening around the world, and has been for several billion years, there are few places on Earth where you can study different stages of continental breakup at the same time. This is because they normally become submerged under water as the Earth’s crust thins, and seawater eventually inundates the rift valley.

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The Rift Valley is different. There is, at its northern end (in Ethiopia) a place called Afar, which sits at the meeting point of three rifts . These are called the Red Sea Rift, the Gulf of Aden Rift, and the Main Ethiopian Rift (see the map below).

The Red Sea Rift has been spreading for the last 23 million years , and the Main Ethiopian Rift for the last 11 million years . There are active volcanoes across all three of these rifts. In Afar, all three rifts are at least partly exposed, with the Red Sea Rift and Main Ethiopian Rift having the most exposure.

Volcanic rocks that erupt when Earth’s tectonic plates spread apart provide a window into the inner Earth that wouldn’t otherwise be accessible. Each lava flow and volcano has its own story that is recorded in the rock and we can learn about that through geochemistry – the concentrations of the elements that make up the rock – and mineralogy – the minerals within the rock.

Analysing these things can tell us about the depth at which the melting rock formed and roughly where in the Earth’s mantle it formed. In our new study, we analysed over 130 new lava samples, obtained from the Afar rock repository at the University of Pisa and our own fieldwork.

We used these samples to investigate the characteristics of the mantle beneath this rifting, when tectonic plates are moving apart from each other. These samples are from Holocene eruptions (rocks younger than 11.7 thousand years old) from across Afar and the East African Rift.

Since the 1970s, scientists have believed that there is a mantle plume beneath the Afar region. Mantle plumes are a portion of abnormally hot mantle (around 1,450°C) or unusual composition of the mantle (or both) below the Earth’s surface. Scientists think it pushed some of the mantle to the Earth’s surface. Our study not only confirms the presence of a mantle plume in this region, but also gives scientists details about its characteristics.

We discovered that the mantle plume beneath the region rises beneath the tectonic plates in pulses, and the pulses have slightly different chemical compositions.

There are mantle plumes around the world. They can be identified in the geological record as far back as several billion years . Each of the plumes has different characteristics – with their own unique chemical composition and shape.

One mantle plume still active today is the one lying below the Hawaiian islands. These islands are part of the Hawaiian Emperor chain, formed over the last 80 million years or so , and are still forming today. The islands originate from the Pacific tectonic plate slowly moving across the top of a mantle plume, making lava bubble up, erupt and eventually solidify as rock.

This plume melts the Earth’s mantle and forms magma, which over long periods results in the formation of an island chain or breaks up continents. It can also form volcanoes along a rift in the Earth’s crust, as we see in east Africa. The Hawaiian plume signature comes from two chemical compositions rising up through the mantle together like two vertical strands.

While scientists have long thought there probably is a plume underneath Afar, what it looks like is debated .

In our study, we created several scenarios of what the plume looks like and then used mathematical modelling to see which plume scenario best fit the sample data. Using this data-driven approach, we show that the most likely scenario is a singular plume that pulses with different chemical compositions.

The three rifts in Afar are spreading at different rates. The Red Sea Rift and Gulf of Aden Rift are moving faster at about 15mm per year (that’s half the rate your fingernails grow at) compared to the Main Ethiopian Rift moving at about 5mm per year . We deduced that the pulses are flowing at different speeds along the stretched and thinner undersides of the tectonic plates.

All this shows us that the motion of tectonic plates can help focus volcanic activity to where the plate is thinner.

This finding has important implications for how we interpret volcanic and earthquake activity. It may indicate that volcanism could be more likely to occur in the faster spreading and thinner portions of the rift, as the flow beneath replenishes the magma more frequently.

However, the eruptions here may be less explosive than the slower spreading rifts. This fits observations that explosive eruptions occur more frequently in the Main Ethiopian Rift (which sits on a thicker part of the plate and where the volcanoes are more mature), compared to the Red Sea Rift.

Our understanding of the link between continental rifting and mantle plumes is still in its infancy but research is already providing insights into how tectonic plates affect mantle plumes and how this might be recorded in the future seafloors of Earth.

Emma Watts works for Swansea University. She receives funding from Natural Environment Research Council and the UK Research Council.

Derek Keir works for the University of Southampton. He receives funding from the Natural Environment Research Council.

Thomas Gernon works for the University of Southampton. He receives funding from the WoodNext Foundation, a donor-advised fund program, and from the Natural Environment Research Council.

/Courtesy of The Conversation. This material from the originating organization/author(s) might be of the point-in-time nature, and edited for clarity, style and length. Mirage.News does not take institutional positions or sides, and all views, positions, and conclusions expressed herein are solely those of the author(s).

Geologists have stumbled on what they call gigantic fortresses lying almost 1,800 miles below our feet in Earth’s mantle.

New seismic evidence shows how these subterranean bulwarks are older and tougher than the cooler debris of dead ocean plates that surround them, turning a long‑running mystery into a concrete data story.

Each fortress spans an area comparable to a continent beneath Africa and the Pacific, and registers hotter than its frigid surroundings.

Utrecht University‘s seismologist Arwen Deuss, working with colleagues across Europe, Australia, and the United States, led the crew that pieced together the picture.

Fortresses in Earth’s mantle

The scientific shorthand for the fortresses is large low seismic velocity provinces or LLSVPs, continent‑scale masses perched at the core‑mantle boundary about 1,800 to 1,900 miles down.

They dampen shear waves and slow them, marking them out as zones of hot, sluggish rock that differs sharply from the stiff material around them.

Seismic tomography first lit them up in global maps during the 1990s. Two hulking blobs emerged, one under Africa and one under the central Pacific, each more than 3,000 miles across.

Later surveys confirmed that the African LLSVP towers roughly 600 miles high while its Pacific twin rises even farther.

Yet whether they were temporary stains or ancient fixtures remained unsettled, in part because most models assumed vigorous, homogenizing flow in the lower mantle.

Taken together, the two provinces occupy about eight percent of the mantle’s volume, a reminder that Earth’s interior is far from uniform.

Listening to the planet’s bell

Seismologists treat the Earth like a giant bell that rings when a great quake strikes. The catastrophic 1994 Bolivia event provided tones that hummed for hours, carrying clues from the deepest layers and offering clean, low‑noise data.

“Large earthquakes make the whole Earth ring like a bell with different tones,” said Deuss after reviewing decades of records.

Her team tuned in not only to the pitch shifts but also to how loudly each mode persisted, a seldom‑used metric called quality factor.

That loudness, known as damping, revealed something odd. Vibrations grew quiet in the cold slab graveyard but stayed loud inside the hot fortresses, implying low internal friction and unexpectedly efficient energy transmission.

Against expectation, the LLSVPs sapped little energy from the waves. The finding overturned the simple view that heat alone controls attenuation, forcing scientists to search for another variable.

Texture tells a deeper story

The key lies in grain boundaries, the microscopic seams between crystals in mantle minerals. Fewer seams mean fewer places for energy to bleed away, a principle familiar to anyone who has tried to push water through a coarse versus fine filter.

Subducted plates recrystallize into tiny grains as they plunge, multiplying boundaries and soaking up seismic energy. They show up as the quietest patches in the global map, matching the high‑damping ring around the Pacific.

Inside the fortresses, grains have had eons to grow fat. Large crystals line up like chunky bricks, stiffening the rock and letting waves glide through with little loss, a behavior confirmed in high‑pressure laboratory rigs.

Laboratory tests on olivine confirm the trend, showing that doubling grain size can nearly halve seismic attenuation at mantle temperatures.

That experimental curve fits the numbers seen in the new global model, strengthening the grain‑size explanation.

Restless mantle and giant fortresses

Modeling suggests the grain growth needed to reach that size takes at least 500 million years, perhaps far longer.

The fortresses, therefore, predate many supercontinents that have since broken apart, including Pangea and its earlier cousins.

Such rigidity helps them ignore the slow churn of mantle convection. They stand their ground while cooler slabs crawl and sink around them, like boulders lodged in a riverbed of flowing rock.

“There is less flow in Earth’s mantle than is commonly thought,” Deuss explained, noting that the presence of these immovable masses forces scientists to rethink convection cycles. The textbook picture of a well‑stirred mantle no longer fits.

A layered mantle, part conveyor and part castle, now seems more likely. That hybrid view changes every surface process driven from below, from the drift of continents to the cycling of carbon.

Why the finding matters at the surface

The hot edges of the fortresses appear to be launchpads for mantle plumes that punch up to volcano chains such as Hawaii. Their buoyant rise fuels not only island arcs but also the massive basalt floods seen in Earth’s deep past.

Large igneous provinces linked to mass extinctions tend to cluster above these plume zones. Knowing that the plumes come from fortress margins ties surface cataclysms to deep‑mantle architecture.

Mountain belts form where plates collide, but the deep heat flow that drives those collisions may trace back to these hot roots. In that sense, the fortresses could set the tempo of orogeny and rifting alike.

Over geologic time, their stability may even shape the drift path of continents, steering plates around the mantle’s slow‑moving keystones. That possibility will feed new computer models that link deep convection to plate motions.

What scientists will chase next

Researchers plan denser global arrays and machine‑learning tools to catch fainter normal modes. Each new quake becomes another flashlight aimed into the depths, refining the 3‑D map with every event.

Geochemists will compare volcanic rocks to lab‑made analogs, hunting chemical fingerprints of the fortresses.

A match would close the loop between seismic images and real material, settling the debate over whether the fortresses differ in composition as well as temperature.

Mineral physicists also want to recreate fortress conditions in diamond‑anvil presses, squeezing and heating samples to map how grain growth unfolds through deep time. The work could reveal why some minerals coarsen while others stay fine and brittle.

Meanwhile, geoneutrino observatories may soon detect radioactive decay signatures that differ inside and outside the fortresses.

Any contrast would add a new dimension to the planet‑sized puzzle, linking deep geology to particle physics.

The study is published in Nature.

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Researchers at the Yale School of Public Health have discovered the evolutionary rhythm of gene expression, showing that changes happen at strikingly varied rates.

In the study, published in Molecular Biology and Evolution, “we found that some genes’ expression patterns remain virtually frozen in place for hundreds of millions of years, while others adapt quickly, evolving their expression rapidly,” said Dr. Jeffrey Townsend, PhD, the study’s senior author, Elihu Professor of Biostatistics and Professor of Ecology and Evolutionary Biology at YSPH. “Knowing these rates of evolution shows us which genetic functions are the unchanging heartbeat of life—and which are evolution’s improvisations.”

A Molecular Clock for Gene Expression

Gene expression—the process by which DNA is transcribed into RNA and then translated into proteins—is central to how organisms develop and respond to their environments. Evolutionary shifts in DNA sequence have been documented, but changes in gene expression have been harder to quantify over long periods of time.

Knowing these rates of evolution shows us which genetic functions are the unchanging heartbeat of life—and which are evolution’s improvisations.

To tackle this challenge, Townsend led a team of investigators that examined over 3,900 genes in nine fungal species with comparable biological developmental stages. The team used diverse fungi for their analysis because they are easy to grow in a common environment. Because the species were meticulously cultured under identical conditions, it allowed the scientists to measure only genetic, not environmental, differences.

Lead author Yen-Wen Wang, PhD, a postdoctoral researcher in Townsend’s lab, applied sophisticated statistical models to infer how frequently gene expression doubled or halved across millions of years of evolution. For most genes, the time ranged from 400 to 900 million years. But some genes—particularly those involved in early spore germination—evolved much faster, in just 6.9 million years.

“This early germination stage is ecologically crucial,” explained Wang. “Fungi must adapt rapidly to capitalize on distinct ways to colonize environments and rapidly acquire nutrients. Their early germination genes are under strong pressure to change.”

At the Heart of Life, Essential Expression Endures

By analyzing gene function across biological pathways, the researchers found that evolution tends to act more quickly on genes involved in flexible, responsive tasks—such as carbon metabolism—than enduring processes such as meiosis, a key aspect of sexual reproduction.

“These findings reveal how the role a gene plays in development affects the pace at which its expression evolves,” Townsend said. “If a gene is part of an ancient, important, tightly regulated process like meiosis, it can’t accommodate change. But if it’s in a metabolic pathway that responds to environmental shifts, there’s more room for evolutionary experimentation.”

Unlocking Life’s Potential

The study establishes a powerful new framework for investigating gene evolution.

“Knowing which genes evolve quickly or slowly in their expression enables us to precisely target genes that are optimal targets for functional characterization and applications in nearly all fields of life sciences,” Townsend said, adding that it could be useful in biotechnology applications ranging from agriculture to medicine.

The work was funded by the U.S. National Science Foundation and National Institutes of Health. The data and methodological approach are publicly available. The researchers hope others will be inspired to expand our knowledge of gene expression in other key areas.

“Ultimately,” Townsend said, “we want to understand how the choreography of gene expression — its timing, location, and intensity — has evolved to build the immense diversity of life we see today.”

Transcriptome data from the study are publicly available in the Gene Expression Omnibus under PRJNA1171587 and PRJNA1177519.