Subglacial Granite Shield Discovered Beneath West Antarctica's Ice Sheet, Reshaping Glacier Behavior Models

In October 2025, the scientific community received compelling evidence regarding the existence of substantial geological formations hidden beneath the ice cover of West Antarctica. Researchers from the British Antarctic Survey (BAS) announced they had located a massive granite plate, stretching approximately 100 kilometers in length, situated directly underneath the grounding line of the Pine Island Glacier. This colossal formation, estimated to be 7 kilometers thick, provides the long-sought explanation for the pink granite boulders previously discovered atop the volcanic summits of the Gudzin Mountains.

These scattered stones, which stood in stark contrast to the surrounding landscape, had long represented a persistent geological enigma. Scientists were able to definitively link them to a single, buried massif by correlating their locations with specific gravimetric anomalies detected during aerial surveys. Radioisotope analysis further confirmed that the granite itself crystallized during the Jurassic period, roughly 175 million years ago, making it considerably older than the majority of the adjacent rock formations. This breakthrough relied heavily on cutting-edge aerospace technology, specifically high-precision gravity measurements gathered from specialized aircraft, including the Twin Otter.

Dr. Tom Jordan, who served as the lead author of the study, emphasized that this finding offers invaluable insights into the dynamics of the Antarctic landscape. Understanding the geology of the subglacial bed is paramount because it dictates how the ice slides across the base and, crucially, how meltwater is drained away. These factors directly influence the rate of ice loss in rapidly changing regions, such as the Pine Island Glacier, which currently ranks among the most intensely melting glaciers across the entire Antarctic continent.

The newly acquired data allows for a significant refinement of computer models designed to forecast the behavior of the ice sheet and, consequently, to assess the risks associated with global sea level rise. Analyzing how the ice moved historically—for instance, during the last glacial period approximately 20 thousand years ago—enables scientists to calibrate these predictive instruments with greater accuracy. Hidden geological features, such as this newly mapped granite shield, serve as crucial benchmarks, pointing toward the deep-seated mechanisms that govern the planet's ice state.

This revelation fits seamlessly into the larger picture of ongoing regional changes. Earlier investigations, dating back to 2017, had already identified a complex topography beneath the Pine Island Glacier, which impacts its friction and flow velocity. Furthermore, it is well established that the thinning and retreat of this glacier commenced as far back as the mid-1940s, a phenomenon generally attributed to climate-related events. Therefore, the identification of this granite plate confirms that the geological foundation establishes the boundary conditions for the ice cover, while external climatic factors activate these latent potentials, driving the pace of glacial change.