How mantle waves and uplift shaped the East Antarctic Ice Sheet formation

East Antarctica sits atop the largest ice reservoir on Earth, a stage where two enduring questions meet. First, why did the East Antarctic Ice Sheet form around 45 million years ago, during the Eocene–Oligocene transition, while the Arctic remained largely ice-free for another 25 million years? Second, why did Southern Ocean surface temperatures stay stubbornly warm for about a decade after the ice began to grow, contradicting a simple cooling narrative? The stakes are diagnostic: they constrain how we model ice-age dynamics and how rapidly ice sheets respond to climate change. The hidden conflict is that cooling alone cannot explain the timing or the regional theatre of growth; a deep-time geological trigger must have preconditioned the landscape. The direction of this analysis is to fuse tectonics with climate, showing how uplift driven by slow mantle waves set the stage for the East Antarctic Ice Sheet formation.

Analytics through data and modeling

The new synthesis traces the first moves not at the surface but in the mantle. Gondwana’s breakup channeled heat and mantle flow under the separating plates, creating wave-like disturbances that travel more than a thousand kilometers through the crust and upper mantle. In two Nature papers, we documented that these mantle waves can trigger diamond-bearing volcanic eruptions and other magmatic pulses deep below the continents, indicating a mechanism that repeatedly pries apart deep roots of crust and mantle. These deep-seated tectonics, not surface climate alone, seeded a slow destabilization that would shape continents for tens of millions of years.

Using landscape-evolution models that simulate tens of millions of years of change, we traced how a mantle-wave upwelling near the coast of East Antarctica stripped away deep rock and lofted the land. The result is an escarpment more than two kilometers high at the coastline and inland uplift that propagates over time. The models show a standing wave of uplift that migrates roughly 1,000 kilometers inland, reshaping the bedrock before ice appears on the surface. This slow tectonic reconfiguration is the undercurrent to the later ice-sheet story.

Crucially, the elevation change matters for a simple physical reason: temperature falls about 1°C for every 100 meters of altitude. The uplift crosses a threshold around the Gamburtsev region, pushing the mountains above roughly 2 kilometers in elevation. Below that threshold, summer melt outpaces accumulation; above it, snow can persist and accumulate. Our simulations indicate that by about 45 million years ago enough of East Antarctica’s topography crossed that threshold for mountain glaciers to take hold and begin to spread. The East Antarctic Ice Sheet formation thus begins as a tectonic process that creates the right landscape for ice to survive the summers.

Once glaciers set in, two feedback loops accelerated the growth. First, snow and ice amplify albedo, reflecting more solar energy and damping regional warming. Second, cooler air reduces atmospheric water vapor, a potent greenhouse gas, weakening the layer of insulation that traps heat. In combination, these mechanisms drove the regional climate colder than would be expected from CO2 decline alone, enabling the ice sheet to extend from highland refugia toward the coast and link with ocean-locked ice to form the single modern expanse of the East Antarctic Ice Sheet formation.

A tale of two poles: contrast with the Arctic

The most striking mismatch sits in timing. A global cooling signal arises from CO2 decline and the long-term trend toward cooler global temperatures, yet the Arctic did not mirror East Antarctica’s rapid ascent into ice. The difference lies in topography and local climate feedbacks. The East Antarctic plateau’s elevation created a local cold trap, while the Arctic lacked similar relief to sustain year-round snow at comparable latitudes for tens of millions of years. This mismatch shows that geography can override a straightforward climate narrative.

As our results show through paleoclimate proxy data and digital-evolution experiments, the Arctic’s trajectory remained constrained by lower elevations and different ocean-heat exchange. The Southern Ocean’s warmth after initial glaciation was compatible with a mountain-forming landscape that was still adjusting to new uplift, isostatic rebound, and ocean-ice interactions. The net effect: the Arctic felt the global cooling but did not reach its own topographic threshold until much later, leaving East Antarctica as the climate’s earliest container for a continental ice sheet.

• Topographic threshold matters: elevation raises the local freezing point and promotes snow retention.
• Isostatic rebound matters: bedrock responds to load by uplifting, extending ice-friendly areas inland.
• Ocean-ice interactions matter: Southern Ocean warming persisted, delaying a uniform cooling of adjacent seas.

From mantle waves to ice: cause-and-effect

We can map a causal chain that links deep Earth processes to surface ice. Gondwana’s breakup triggers mantle convection patterns that generate mantle waves beneath East Antarctica. These waves destabilize the continent’s deep roots over tens of millions of years, producing mantle-derived uplift and crustal thinning that contribute to long-wavelength surface tilting and erosion. This is the hidden cause behind the ice-sheet’s eventual land-ice growth rather than a simple atmospheric cooling story.

In coastal regions, uplift forms an escarpment and removes rock deep beneath the land. The crust thins, and the overlying mantle structures adjust, so that the Gamburtsev mountains rise and eventually exceed the critical altitude for snow persistence. This uplift happens gradually, but the timing aligns with the onset of continental glaciation roughly 45 million years ago, when global temperatures had already fallen but the local landscape was ready to trap ice.

• Elevation threshold: roughly 2 km marks the line where snow can persist year-round in East Antarctica.
• Ice-albedo feedback: once ice persists, albedo increases and temperatures drop further, reinforcing accumulation.
• Moisture and greenhouse effects: drier air reduces greenhouse trapping and accelerates cooling in the region.

The combination of these steps yields a plausible timeline: uplift reaches the Gamburtsevs after about 100 million years of inland propagation, ice begins to form on higher ground, and within a few million years, the first extensive ice body stabilizes along the coast. That stability then evolves into the modern East Antarctic Ice Sheet formation, whose existence hinges on this slow tectonic preconditioning rather than on an abrupt climate shock alone.

Expert reconstruction: implications for past and future ice sheets

The synthesis reframes the origin of continental ice sheets. It suggests that the height of the land—generated by deep Earth dynamics long before climate becomes favorable—establishes the capacity of a region to host ice. When the climate then cools sufficiently, those topographic conditions determine whether ice sheets form at all, and how far they spread. In East Antarctica, the mountains and plateau provided a stable base for multi-million-year ice growth, while the Arctic remained comparatively low and less conducive to sustained accumulation.

These findings have implications beyond the last 40–50 million years. If deep Earth processes can unlock a preconditioning terrain for ice ages, then earlier episodes may have depended on a similar interplay of tectonics, uplift, and ocean heat exchange. This means that predicting future ice-sheet responses to warming requires paying attention to bedrock history as well as atmospheric CO2 trajectories. The lesson is cautious: once ice sheets melt, they can disappear rapidly, but their re-formation is unlikely unless the preconditioned landscape is rebuilt over geological timescales.

We should treat the East Antarctic Ice Sheet formation as a case study in long-range causality—where the stage was set by mantle waves and continental drift, not only by climate. The broader takeaway is a more nuanced view of ice ages: the path to a snow-covered world depends as much on bedrock height and tectonic history as on atmospheric warmth or its absence. As researchers refine the models and gather more paleoelevation data, we will sharpen predictions for future ice-sheet behavior under changing global temperatures.

Ultimately, the East Antarctic story demonstrates that climates do not act in isolation from the rocks beneath our feet. Geology conditions ice ages as surely as chemistry does, and the lesson from Gondwana’s breakup onward is clear: the mountains you cannot see may decide the ice you cannot imagine.

Quantifying paleoelevation and uplift rates

To bridge the gap between deep Earth dynamics and surface ice, a quantitative paleoelevation reconstruction uses isostatic rebound data in combination with proxy records. Three pillars provide constraints: bedrock uplift histories, offshore sediment thickness, and isotope-based paleoelevation estimates. In practice, the Gamburtsev region shows inland uplift of roughly 1.5–2.0 km by 45 Ma, enough to create a topographic cold trap for snow persistence. These estimates align with climate proxies showing regional cooling and with albedo feedback reinforcing the cooling trend.

These numbers support the idea that uplift preceded durable ice cover by several million years, giving rise to stable snow zones once temperatures cooled further.

In practical terms, once inland topography crosses the threshold, local climate feedbacks can sustain snow lines despite CO2 fluctuations.

• Mantle-wave upwelling beneath East Antarctica
• Crustal thinning and bedrock uplift inland
• Gamburtsev mountains rise above critical altitude
• Coastal glaciation expands inland; ice sheet forms

These elements together outline a pathway where deep Earth processes precondition the surface for ice formation, aligning tectonics with climate signals to explain the East Antarctic Ice Sheet’s emergence.

What mechanism links mantle waves to East Antarctica ice sheet formation?

Mantle-wave upwellings generated by deep mantle convection beneath East Antarctica began long before surface cooling produced sustained ice, progressively uplifting the coastal crust and inland Gamburtsev region by roughly two kilometers and thinning deep roots; this gradual build created a topographic cold trap that allowed snow to persist through seasonal warming, setting the stage for an ice-sheet foothold once global temperatures dropped, a sequence supported by landscape evolution models, offshore sediment proxies, and isotope trends that together indicate tectonics primed the land for ice before climate fully favored glaciation. This link is reinforced by isostatic rebound signals and eroded surface patterns that match the timing of early glaciation.

Why did East Antarctica form earlier than the Arctic?

The East Antarctic plateau reached elevations that produced a local cold trap, while the Arctic remained relatively modest in height and was more exposed to ocean heat exchange; thus, even as CO2 fell globally, East Antarctica could maintain year‑round snow due to topography and regional climate feedbacks, whereas the Arctic required a separate threshold of uplift and ocean-ice interaction to sustain persistent accumulation. This topographic advantage explains why East Antarctica prefigured a continental ice sheet ahead of the Arctic in the long cooling trend.

How is paleoelevation estimated for the 45‑million-year timeframe?

Estimations combine isostatic rebound models, offshore sediment thickness, detrital thermochronology, and isotope-based proxies (e.g., oxygen isotopes reflecting temperature and elevation), integrated with crustal thinning data from geophysics; by cross‑validating these lines, researchers constrain elevation changes to a plausible range (roughly 1.5–2.0 km inland by 45 Ma in East Antarctica). This multi-proxy approach reduces ambiguity and anchors tectonic uplift within a tangible climate context, supporting a preconditioning narrative for ice growth.

What are the main feedbacks that stabilized the ice sheet after its formation?

Two key feedbacks operate: ice-albedo feedback, where increased surface reflectivity drives regional cooling and further snowfall, and moisture balance changes, where reduced atmospheric water vapor weakens greenhouse trapping, allowing cooler surface temperatures to persist locally. In addition, ocean-ice interactions in the Southern Ocean help sustain cold coastal regimes that support continued ice growth. Together, these mechanisms convert initial uplift into a self-reinforcing ice-sheet state even as global climate oscillates.

How might these findings affect predictions of future ice sheets under warming climates?

If deep-Earth preconditioning scripts regional ice-sheet potential, then bedrock history and uplift history must be integrated into predictive models alongside atmospheric CO2 trajectories; areas with a strong tectonic uplift history may respond differently to warming, showing resilience or vulnerability based on elevation thresholds and isostatic rebound capacity. The broader implication is a more nuanced forecast where geology and ocean dynamics modulate climate-driven ice-sheet change, rather than climate alone determining outcomes.