An international team of researchers led by the University of Edinburgh has used satellite data and the physics of ice flow to successfully map Antarctica’s hidden landscapes in unprecedented detail, revealing a tantalizing array of geological structures that shape the surface ice sheets from below.
Described by the research team as “one of the Solar System’s least mapped planetary surfaces,” Antarctica’s subglacial bedrock has remained hidden for millennia beneath massive layers of solid ice, making the new map an invaluable tool for understanding the continent’s history and evolution.
The map will also help scientists plan future survey efforts by pointing the way to the most valuable study targets, and potentially improve models designed to forecast sea level changes caused by climate change.
“The findings not only improve ice sheet models but can also guide future geophysical surveys and reduce uncertainty in projections of ice loss and sea-level rise,” they explained.
Antarctica’s subglacial topography directly affects the ice flow, and it also helps shape the continent’s surface. Previous studies have confirmed the existence of jagged hillsides, mountain ridges, vast plains, and other geological structures. However, researchers have often relied on incomplete information about this hidden landscape, which is needed to accurately predict how Antarctica will respond to climate change, due to the thick sheets of solid ice stacked on its surface.
“Because making scientific observations through ice is difficult, we know less about the landscape hidden beneath Antarctica than we do about the surface of Mars or Venus,” explained Dr Helen Ockenden, a researcher at L’Institut des Géosciences de l’Environnement in Grenoble, France, and leader of the new mapping effort during her PhD at the University of Edinburgh.
To fill some data gaps, Dr Ockenden and colleagues collected high-resolution satellite observations of the ice sheet’s surface, a series of ice thickness measurements, and an Ice Flow Perturbation Analysis (IFPA), which they said “leverages the physics of how ice flows over underlying bedrock topography.”
After combining the data, an entirely new map revealed previously hidden topographic features ranging as deep as 30 kilometers beneath the ice’s surface. According to the study, these features included deep and narrow alpine valleys, scoured lowlands, and extensive, buried fluvial channels hundreds of kilometers long. Although many of these features formed from the pressures and movement of the ice, the researchers suspect some may be “relics” that predate the modern layers of ice.
(A) shows the IFPA subglacial topography for the whole Antarctic continent and (B to D) show a comparison of different bed topography maps for the Pensacola-Pole Basin region [outlined in black on (A). Image credit: Ockenden et al.
Other details uncovered by the new map of Antarctica’s hidden landscape included specific geological aspects of the continent’s mountain ranges, deep canyons, and wide valleys. The research also uncovered approximately 30 thousand previously unknown small hills and valleys spread across the continent.
When discussing their map-building approach, Bingham said combining the two types of data allowed the team to observe “the relative distributions of these highly variable landscapes over the whole continent” for the first time.
“It’s really exciting that this new method allows us to use satellite measurements of the ice surface to fill all of the gaps in our maps, revealing new details about mountain ranges, canyons, and geological boundaries,” Dr Ockenden added.
In a related perspective, researcher Duncan Young acknowledged the potential scientific value of a map of Antarctica’s hidden landscape while noting that the map produced by Dr Ockenden and colleagues should not be considered the “final word” on Antarctic geography.
“Similar to mass conservation methods, the analysis relies on major assumptions about mechanisms that are critical for modeling ice sheet evolution,” Young explained, “such as ice deformation, basal sliding, and melt and freeze processes at the ice-bedrock interface.”
When discussing the importance of filling in missing, detailed information about the landscape beneath Antarctica’s ice sheets, study co-author Professor Mathieu Morlighem from Dartmouth College, said it is critical for ice sheet models, especially in “rougher areas” where higher levels of hills and valleys can slow down ice retreat more than flatter areas.
“This new map will help our models to produce better projections of where and how much sea levels will rise in the future,” Professor Morlighem explained.
Along with providing new data on Antarctica’s hidden landscape, study co-author Professor Andrew Curtis from the University of Edinburgh said the team’s method, or projecting ice surface information from satellites down to the base of the ice, “provides a completely new way to see through” the continent’s massive layers of surface ice.”
“Over several years, we have proven that it works well in detailed tests, and this application across all of Antarctica demonstrates its power,” Professor Curtis explained.
The study “Complex mesoscale landscapes beneath Antarctica mapped from space” was published in Science.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.