Ancient mantle waves from the breakup of Africa and Antarctica helped uplift East Antarctica’s interior (including the Gamburtsev Mountains), creating highlands cold enough for permanent snow and ice around 34 million years ago and giving Antarctica a head start on glaciation while the planet was still relatively warm.

Mantle waves are slow-moving convective instabilities in Earth’s upper mantle, triggered by continental rifting and breakup.

They migrate inland beneath continents over tens to hundreds of millions of years, eroding the base of the lithosphere (especially thick cratonic keels) and driving isostatic surface uplift. This process links deep-Earth dynamics to surface topography, erosion, and even diamond-bearing volcanism.

The concept was developed primarily by Thomas Gernon and colleagues (University of Southampton and collaborators) through geodynamic modeling and applied to both kimberlite eruptions (2023 Nature) and continental uplift and plateau formation (2024 Nature).

It was then extended to explain the uplift that preconditioned East Antarctica for ice-sheet nucleation.

How mantle waves form and propagate

Trigger — continental rifting and breakup
When a continent stretches and rifts (e.g., Africa- Antarctica separation during Gondwana breakup in the Jurassic), the lithosphere necks and thins. Hot asthenospheric mantle upwells into the gap created by extension.

Initiation of instabilities
The steep lithosphere- asthenosphere boundary (LAB) at the rift edge drives edge-driven convection. Hot mantle material cools against the cold continental base, becomes denser, and sinks. This sets up Rayleigh–Taylor-type convective instabilities (analogous to the rising/sinking blobs in a lava lamp).

Propagation as a “wave”
These instabilities do not stay localized. They migrate cratonward (inland) along the base of the lithosphere at roughly 15- 20 km per million years (about a millionth of a snail’s pace). The wave can travel hundreds to >1,000 km inland over 50–100+ million years.

Erosion of the lithospheric keel
As the wave advances, it scours and removes the lowermost ~30- 40 km of the continental root (the thermal boundary layer or weaker parts of the cratonic keel). This material is swept into the mantle.

Isostatic uplift
Removing dense material from the base lightens the lithosphere. By isostasy (the principle that Earth’s outer layers float in gravitational equilibrium), the surface rises, like a ship rising higher after unloading cargo or a hot- air balloon ascending after dropping ballast. Typical uplift produces stable plateaus ~1- 2 km high.

Surface and geological consequences

Great escarpments and elevated plateaus — Escarpments form and retreat slowly (~1 km/Myr) by erosion at the rifted margin. Simultaneously, the faster- migrating mantle wave uplifts the craton interior, creating a high plateau. A wave of surface denudation (erosion) follows the uplift, recorded in thermochronology data. This explains features such as southern Africa’s Great Escarpment and Drakensberg plateau, and analogous structures in East Antarctica (coastal escarpment and elevated plateau and Gamburtsev Mountains).

Kimberlite (“diamond volcano”) eruptions — Removal of keel material allows hot asthenosphere to upwell in the return flow. This can partially melt carbonated mantle, generating small- volume, volatile- rich kimberlite magmas that erupt explosively and can carry diamonds from depth. Kimberlite pulses often peak ~20- 30 million years after continental breakup and migrate inland at rates matching the mantle wave.

Landscape evolution and climate links — Long- term uplift changes elevation, river gradients, erosion rates, and regional climate. In the Antarctic case, it raised highlands above the threshold for permanent ice accumulation (~2 km), enabling the East Antarctic Ice Sheet to nucleate ~45- 34 million years ago even while global temperatures were relatively warm.

Key characteristics

• Extremely slow (geological timescales only).
• Self-propagating once initiated by rifting.
• Primarily affects thick, old continental lithosphere (cratons).
• Challenges the older view of cratons as permanently stable; they can be progressively destabilized from below after breakup.

Mantle wave dynamics describe a slow, self-propagating convective process in Earth’s upper mantle initiated by continental rifting. These waves erode the base of thick continental lithosphere (especially ancient cratonic keels), drive long- term isostatic surface uplift, and can trigger specialized volcanism. The process operates on timescales of tens to hundreds of millions of years.

When a continent begins to stretch and break apart (rifting), the lithosphere thins and necks. Hot, buoyant asthenospheric mantle rises to fill the space created by extension.

This creates a steep topography at the lithosphere– asthenosphere boundary (LAB) along the rift edge. The contrast between the cold, rigid continental root and the hot, mobile asthenosphere drives edge- driven convection:

• Hot mantle material flows toward the cold base of the continent.
• It cools, densifies, and sinks.

This sets up initial convective cells analogous to the rising and sinking blobs in a lava lamp.

The initial edge-driven flow destabilizes the thermal boundary layer at the base of the nearby continental lithosphere. This triggers a chain of Rayleigh- Taylor instabilities (gravitational overturns where denser material sinks into less dense material below, or vice versa).

These instabilities do not remain stationary. They organize into a coherent, migrating “wave” that propagates cratonward (inland, away from the rift) along the base of the lithosphere at a characteristic speed of roughly 15- 20 km per million years.

Over geological time this allows the disturbance to travel hundreds to more than 1,000 km into the continental interior. The wave is sustained by continuous interaction between the convective mantle flow and the lithospheric root.

As the mantle wave advances, it progressively scours and removes the lowermost 30- 40 km of the continental root (the weaker, thermally defined part of the keel). Material is entrained and swept downward into the deeper mantle.

This “underground erosion” is selective: thicker, colder cratonic keels are particularly susceptible once the process is under way. Removed material is replaced by hotter asthenosphere in the return flow of the convection cell.

Removal of dense lithospheric material reduces the overall density of the column. By the principle of isostasy (gravitational equilibrium of Earth’s outer layers floating on the denser mantle), the surface rises.

Analogy: a cargo ship rises higher in the water after unloading heavy freight, or a hot- air balloon ascends after dropping ballast. Typical modeled surface uplift produces stable elevated plateaus of 1- 2 km height. The uplift migrates inland following the mantle wave.

Secondary effects

Surface erosion wave — Uplift steepens rivers and increases denudation. A wave of erosion propagates across the landscape at a comparable or slightly slower rate, recorded in low- temperature thermochronology data.

Magmatism — Upwelling hot asthenosphere in the return flow can cause small- degree partial melting of carbonated mantle, generating kimberlite magmas. These volatile-rich melts ascend rapidly, sometimes carrying diamonds, and erupt as “diamond volcanoes.” Kimberlite pulses often lag continental breakup by ~20- 30 million years and migrate inland at rates matching the mantle wave.

Landscape architecture — The process simultaneously creates a steep coastal/rift- margin escarpment (which retreats slowly by headward erosion at ~1 km/Myr) and a high inland plateau.

Timescales and rates

Propagation speed: ~15– 20 km/Myr.

Duration of significant activity after a major breakup: tens to >100 million years.

Surface expression develops gradually and can persist long after the original rift has become a passive margin.

Mantle waves are slow- moving disturbances deep in Earth’s mantle. They form when tectonic plates separate; the waves then travel beneath a continent, remove material from its base, and cause surface uplift. The separation of Africa and Antarctica (starting in the Jurassic, >120 million years ago) launched such waves under East Antarctica. This gradually raised the continent’s interior.

Before ~50 million years ago, most of the Gamburtsev range was below ~1.5 km elevation. By 34 million years ago, nearly half stood above ~2 km, high enough for year- round snow rather than seasonal melt. Air temperature typically falls by up to ~1°C per 100 m of elevation gain, so the uplift created colder highland conditions even while lower elevations and the broader planet remained warmer.

Researchers integrated geodynamic models, topographic reconstructions, ice-sheet simulations, and energy-balance calculations. The models reproduced the evolution of a ~2 km coastal escarpment, elevated plateau, and inland mountains that seeded the East Antarctic Ice Sheet.

Once ice formed in the highlands, albedo feedback (bright ice/snow reflecting sunlight) helped cool the planet by roughly 1°C. Cooler air held less water vapor (a greenhouse gas), further aiding cooling and allowing the ice sheet to expand toward the coast. Lower land elevations in the Northern Hemisphere offered fewer similar nucleation sites.

Lead author Thomas Gernon notes that Earth’s interior can precondition landscapes for glaciation, influencing the timing and location of major climate transitions.

The mountains that enabled the ice sheet remain buried beneath it today.

The East Antarctic Ice Sheet is the largest and oldest on Earth and holds enough ice to raise global sea levels by ~52 m if fully melted; understanding the geological factors that helped establish it informs assessments of its long- term stability under warming.

Falling CO₂ alone would be expected to produce more symmetric polar responses.

Geological uplift from ancient mantle waves provided Antarctica with higher, colder terrain that allowed ice to take hold earlier.

The original study is available in Science.

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Continental breakup–driven uplift instigated East Antarctic Ice Sheet formation

The East Antarctic Ice Sheet (EAIS), Earth’s oldest and largest ice mass, equivalent to ~52 m of global sea-level rise, formed at the Eocene- Oligocene Transition (~34 million years ago).

Global climates and Southern Ocean temperatures were still relatively warm at that time (and remained so well into the Oligocene). Declining atmospheric CO₂ is widely accepted as the primary driver, but it does not fully explain how ice sheets could nucleate and expand under those conditions, nor the strong asymmetry with the much later appearance of large Northern Hemisphere ice sheets.

The authors propose that regional topographic uplift, ultimately rooted in Jurassic continental breakup between Africa and Antarctica (>100- 120 million years earlier) and subsequent mantle- surface feedback (“mantle waves”), preconditioned East Antarctica for glaciation.

They integrated:

• Geodynamic and landscape- evolution models,
• Topographic reconstructions,
• Ice- sheet models,
• Energy- balance models.

Landscape modeling shows that breakup generated a >2 km- high coastal escarpment in Dronning Maud Land and an elevated plateau extending ~2,000 km inland.

A wave of uplift and exhumation migrated inland over ~100 million years, reaching and elevating the ancestral Gamburtsev Mountains during the Eocene.

By ~45 Ma, progressive plateau growth had pushed substantial areas above the elevation threshold (~2 km) required for ice- sheet nucleation. This allowed mountain glaciers to form and expand under climates that would otherwise have been too warm.

The resulting ice triggered albedo feedback that cooled the planet by ~1 °C, enough to help the ice sheet spread across Antarctica, but insufficient to glaciate the lower- elevation Northern Hemisphere landmasses at the same time.

Earth’s interior can precondition landscapes for major climate transitions.

Dynamic uplift controlled the timing of EAIS formation, explaining both its early onset relative to the Arctic and its ability to grow while surrounding oceans remained relatively warm.

The study underscores that topography and deep- Earth processes are essential companions to atmospheric CO₂ in understanding the onset of Cenozoic ice ages.

Supplementary data (landscape reconstructions, ice-sheet modeling files) are available via Zenodo.

Published: Science, 2 July 2026

DOI: 10.1126/science.adz6758

Authors: Thomas M. Gernon, Thea K. Hincks, Philip Goodwin, Guy J. G. Paxman, Sascha Brune, Eelco J. Rohling, Derek Keir & Jean Braun

Abstract

Why Antarctica became glaciated ∼34 million years ago (Ma) remains debated, as relatively warm climates and sea temperatures appear inconsistent with ice sheet formation. Although a critical decline in CO₂ is considered primarily responsible, evidence suggests that other factors were important, too. We investigated whether regional topographic uplift, rooted in Jurassic continental breakup and mantle-surface feedbacks, enabled nucleation of the East Antarctic Ice Sheet (EAIS). By integrating geodynamic-topographic models with ice sheet and energy balance models, we show that progressive plateau growth in East Antarctica, including Eocene uplift of the Gamburtsev Mountains, pushed landscapes above the threshold for ice sheet nucleation by ∼45 Ma. Uplift enabled EAIS growth under warmer-than-expected climates, producing hemispheric asymmetry in early glaciation and reconciling Oligocene polar warmth with the onset of the modern icehouse world.