Hidden forces discovered that cause Earth's continents to rise

Scientists have long been captivated by the dynamic forces that shape our planet’s surface, but few questions have puzzled them as much as why some of the Earth’s most stable regions across its continents mysteriously rise to form towering topographic features.

Now, a study led by Professor Tom Gernon, a leading Earth Scientist at the University of Southampton, sheds light on this phenomenon, revealing how deep tectonic processes can cause these seemingly stable areas to ascend dramatically.

Professor Gernon, along with his team of researchers, has discovered that when tectonic plates split apart, powerful waves are triggered deep within the Earth’s mantle. This process causes continental surfaces to rise by over a kilometer.

Their discovery helps resolve a long-standing mystery in the field of plate tectonics while enhancing our understanding of how some of the Earth’s most dramatic landscapes are formed.

Puzzle of rising continents

For decades, scientists have speculated about the forces that create steep, kilometer-high topographic features known as Great Escarpments, such as the one that encircles South Africa.

However, the mystery deepened when researchers observed that even the stable interiors of continents, far from these escarpments, could rise and become eroded. The question was, why?

According to Professor Gernon, scientists have suspected for a long time that steep features called Great Escarpments, like those around South Africa, form when continents rift and split.

However, understanding why the interiors of continents also rise and erode has been much harder to figure out. “Is this process even linked to the formation of these towering escarpments? Put simply, we didn’t know,” he says.

The team’s research, which was a collaborative effort involving experts from the University of Southampton, Helmholtz Centre Potsdam, and the University of Birmingham, focused on the effects of global tectonic forces on landscape evolution over hundreds of millions of years.

Their findings provide a compelling explanation for the vertical motions of the stable parts of continents, known as cratons, one of the least understood aspects of plate tectonics.

Forces beneath our feet

The research team employed advanced computer models and statistical methods to simulate how the Earth’s surface has responded to the breakup of continental plates through time.

What they discovered is that when continents split, the stretching of the continental crust causes stirring movements in the Earth’s mantle, the voluminous layer between the crust and the core.

This process sets off what can be likened to a sweeping motion that moves toward the continents, disturbing their deep foundations.

Professor Sascha Brune, who leads the Geodynamic Modelling Section at GFZ Potsdam, played a key role in this discovery. “This process can be compared to a sweeping motion that moves towards the continents and disturbs their deep foundations,” Professor Brune explains.

The team’s simulations revealed that the speed of these mantle waves closely matches the speed of major erosion events observed in Southern Africa following the breakup of the ancient supercontinent Gondwana.

The scientists pieced together evidence suggesting that the Great Escarpments originate at the edges of ancient rift valleys, similar to the steep walls seen at the margins of the East African Rift today.

Moreover, the rifting event initiates a “deep mantle wave” that travels along the continent’s base at about 15–20 kilometers per million years. This wave convectively removes layers of rock from the continental roots, much like how a hot-air balloon sheds weight to rise higher — a process known as isostasy.

Ripple effect on Earth’s surface

The team’s landscape evolution models reveal how these deep mantle disturbances trigger a wave of surface erosion that sweeps across continents over tens of millions of years. This erosion removes a significant amount of rock, causing the land surface to rise further and form elevated plateaus.

According to Jean Braun, Professor of Earth Surface Process Modelling at GFZ Potsdam, “Our landscape evolution models show how a sequence of events linked to rifting can result in an escarpment as well as a stable, flat plateau, even though a layer of several thousands of meters of rocks has been eroded away.”

This discovery provides a new explanation for the puzzling vertical movements of cratons, far from the edges of continents where uplift is more commonly observed.

Dr. Steve Jones, Associate Professor in Earth Systems at the University of Birmingham, highlights the importance of this discovery. He explains, “This finding makes a compelling case that rifting can, in some situations, directly create long-lasting upper mantle convection cells on a continental scale.”

These convective systems, driven by rifting, significantly impact Earth’s surface topography, erosion, sedimentation, and the distribution of natural resources.

Climate, biodiversity, and continent rise

The implications of this study extend beyond geological understanding. The researchers believe that the same mantle disturbances responsible for the uplift of continental surfaces also influence regional climates, biodiversity, and even human settlement patterns.

As Professor Gernon points out, “Destabilizing the cores of the continents must have impacted ancient climates too.”

Moreover, this research builds on the team’s previous work linking diamond eruptions to continental breakup. The same chain of mantle disturbances that causes diamonds to rise quickly from Earth’s deep interior also plays a fundamental role in shaping continental landscapes.

This interconnectedness between deep Earth processes and surface phenomena highlights the complexity and beauty of our planet’s dynamic system.

New perspective on Earth’s evolution

As scientists delve deeper into the complex interplay between tectonic forces and surface processes, this study paves the way for a richer understanding of our planet’s evolution.

Led by Professor Gernon and his team, this research not only addresses a long-standing question in plate tectonics but also emphasizes the significance of examining deep Earth processes to truly grasp the forces that shape our world.

Professor Gernon aptly notes, “Continental breakup disturbs not only the deep layers of the Earth but also has effects that reverberate across the surface of the continents, previously thought to be stable.”

This study exemplifies the power of collaboration and innovation in unraveling Earth’s mysteries, offering a new perspective on how the surface has transformed over millions of years.

Continent rise and our dynamic planet

The Earth’s surface is anything but static. It is shaped by powerful forces that drive continent formation and craft dramatic landscapes, deeply rooted in the planet’s inner workings.

This important research by Professor Gernon and his team provides valuable insights into these processes, illuminating the intricate relationship between deep Earth dynamics and surface evolution.

As we delve deeper into these mysteries, it’s clear that our planet remains a dynamic and ever-evolving entity, full of surprises waiting to be uncovered.

What does this mean for our understanding of Earth and its future? Our planet’s story is ongoing, and each discovery brings us closer to understanding our place within it.

The study is published in the journal Nature.

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