Antarctica’s Hidden Landscape Revealed: Mountains adn Valleys Beneath the Ice
A new, highly detailed map of Antarctica’s bedrock is challenging long-held assumptions about the continent’s icy surface, revealing a rugged terrain of mountains, valleys, and extensive channel networks buried beneath kilometers of ice. The findings, published this week in the journal Science, have meaningful implications for predicting future sea-level rise and understanding the continent’s complex geological history.
for decades, scientists have known that Antarctica holds enough frozen water to raise global sea levels by many meters. Its vast ice sheet also plays a crucial role in regulating Earth’s climate by reflecting sunlight. Though, accurately predicting how quickly the ice may melt and how much seas may rise requires a detailed understanding of the topography of the bedrock below the ice – a landscape that has remained largely hidden from view.
Traditional methods for mapping the subglacial terrain, such as airborne radar surveys, are expensive, time-consuming, and limited in their coverage. These methods also struggle in areas where the ice is particularly thick or where the bedrock is covered by water. ‘Environnement in France has overcome these limitations with a novel technique called Ice Flow Perturbation Analysis (IFPA).
“The idea behind IFPA is relatively simple,” explained a lead researcher. “Hills and valleys beneath the ice sheet influence how the ice flows, leaving subtle but measurable signatures on the ice surface. by carefully analyzing the shape and speed of the ice using satellite data, and applying the laws of ice motion, we can essentially work backward to infer the topography of the bedrock below.”
The team combined high-resolution satellite elevation data, ice-velocity measurements, and existing ice thickness observations to create a continent-wide map capturing features as small as 2 to 30 kilometers across.After correcting for known survey data, the resulting map provides an unprecedented level of detail about the hidden landscape.
The results are striking. The new map identifies 71,997 subglacial hills rising at least 50 meters above their surroundings – more than double the number found in previous widely used maps. In the Maud subglacial Basin, researchers discovered a steep-sided channel nearly 400 kilometers long, averaging 50 meters deep and six kilometers wide, possibly linking drainage systems from the mountains of Dronning Maud Land to lower-lying regions. Similarly, in Wilhelm II land, newly resolved channels cut across previously undetected ridges, mirroring channel formations observed elsewhere beneath ice sheets.
Further analysis revealed valleys crossing high plateaus, including Hercules Dome, resembling U-shaped alpine glacial valleys observed with airborne radar. these features suggest the presence of ancient mountain glaciers that existed before Antarctica became fully ice-covered. The map also clarifies boundaries between different types of terrain, such as the linear transition between raised central terrain and subglacial lakes in the Recovery Subglacial Basin, hinting at underlying variations in rock type.
Beyond identifying individual features, the research team measured the overall roughness of the subglacial landscape. “Roughness considerably affects how strongly the ice grips the ground, which in turn controls its flow rate towards the sea,” explained Ockenden. “Our analysis shows that rough regions align with areas where surveys indicate uneven bedrock, and importantly, these patterns aren’t simply mirroring existing radar data. IFPA provides a more consistent and physically accurate picture across the entire continent.”
The team classified Antarctica’s hidden terrain into three broad styles: low-relief landscapes, alpine terrain, and areas shaped by selective erosion. They found fewer truly flat regions than previously thought,with many areas appearing textured,suggesting they may be filled with thick sediments rather than solid bedrock. Selective erosion, the process of ice carving away at the landscape, dominates much of the continent, covering approximately 56% of the mapped area.
This new understanding of Antarctica’s subglacial landscape has profound implications for predicting future sea-level rise. By revealing the complexities of the bedrock topography, the research will help improve the accuracy of ice-flow models, leading to more reliable projections of how quickly the ice sheet may melt. The map also guides future exploration, highlighting areas where new airborne and ground surveys should be focused. As one geophysicist noted, the upcoming International Polar Year from 2031 to 2033 presents a “timely opportunity for international collaboration” utilizing methods like IFPA.
Ultimately, unraveling the mysteries of Antarctica’s hidden landscape provides critical insights into Earth’s past climate, its present stability, and its future risks, benefiting coastal planning, climate policy, and global adaptation efforts. The research findings are available online in the journal Science.
