Scientists at the University of Southampton have unlocked one of the most puzzling questions in plate tectonics revealing how and why ‘stable’ parts of continents gradually rise to form some of the planet’s greatest topographic features, such as India’s Western Ghats.
The study, led by Professor Tom Gernon, a leading Earth scientist at the University of Southampton, delved into the effects of global tectonic forces on landscape evolution over hundreds of millions of years. The findings shed light on one of the least understood aspects of plate tectonics—the vertical movements of stable continental regions, known as cratons.
Through their research, the scientists have discovered that when tectonic plates break apart, powerful waves are triggered deep within the Earth that can cause continental surfaces to rise by over a kilometre. This breakthrough provides a new understanding of the dynamic forces that shape expansive topographic features, known as escarpments and plateaus, which profoundly influence the planet's climate and biology.
Tom Gernon, Professor of Earth Science at the University of Southampton and lead author of the study, said: “Scientists have long suspected that steep kilometre-high topographic features called Great Escarpments — like the classic example encircling South Africa, and the famous Western Ghats in India — are formed when continents rift and eventually split apart. However, explaining why the inner parts of continents, far from such escarpments, rise and become eroded has proven much more challenging. Is this process even linked to the formation of these towering escarpments? Put simply, we didn’t know.”
The research team, including Dr Thea Hincks, Dr Derek Keir, and Alice Cunningham from the University of Southampton, collaborated with experts from the Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences and the University of Birmingham. Their results explain why regions previously thought to be 'stable' undergo substantial uplift and erosion, creating elevated areas like the Central Plateau of South Africa and the Deccan Plateau in India.
Building on their previous research linking diamond eruptions to continental breakup, the team employed advanced computer models and statistical methods to investigate the Earth's surface response to the breakup of tectonic plates over time. They found that the stretching of the continental crust during rifting stirs movements in the Earth's mantle, initiating a deep mantle wave that travels across the continent's base at a speed of 15-20 kilometres per million years.
The team's landscape evolution models demonstrated how these mantle-driven processes result in surface erosion that persists for tens of millions of years, lifting land surfaces and forming elevated plateaus. This new explanation for the vertical movements of cratons offers significant insights into the Earth's geological history.
Dr. Steve Jones, Associate Professor in Earth Systems at the University of Birmingham, emphasized the broader implications of the research and said: "Rifting can generate long-lived, continental-scale upper mantle convection cells that profoundly impact Earth's surface topography, erosion, sedimentation, and natural resource distribution."
The researchers also concluded that the same mantle disturbances responsible for rapid diamond eruptions play a crucial role in shaping continental landscapes, affecting factors ranging from regional climates and biodiversity to human settlement patterns.
Professor Gernon, who received a major philanthropic grant from the WoodNext Foundation, administered by the Greater Houston Community Foundation, to study global cooling, highlighted the far-reaching impacts of their findings.
He added: “This groundbreaking study represents a significant leap forward in understanding the forces that shape our planet's surface, offering new perspectives on the intricate connections between Earth's deep interior and its diverse landscapes.”
