Deep under Greenland’s ice sheet, radar images have unveiled strange plume-like structures that distort the ice layers, posing a scientific puzzle. Recent research suggests that these phenomena may be caused by thermal convection, much like what’s seen with molten rock under the Earth’s crust.
Robert Loh from the University of Bergen notes that while this finding feels counterintuitive, the physics make sense because ice is significantly softer than Earth’s mantle. The Greenland ice sheet, which holds a substantial amount of the world’s frozen water, plays a critical role in predicting future sea level rise.
Scientists have utilized ice-penetrating radar to explore these peculiar structures, discovering that they are not influenced by the underlying bedrock. Initial hypotheses included processes like freezing glacier meltwater or movement beneath the ice, but new computer models indicate that convection could create structures resembling those seen in radar images.
In their model, researchers simulated a 2.5-kilometer-thick slice of ice, altering variables such as snowfall and ice thickness. They found that plume formation likely requires warmer, softer ice at the base, suggesting the ice there may be more malleable than previously understood. This heat arises from Earth’s radioactive decay and residual thermal energy accumulated over time.
Although the ice remains solid and flows very slowly, understanding these convection processes is crucial for predicting the ice sheet’s future and its impact on global coastlines. The study emphasizes the importance of continuing research to better comprehend the inner workings of Greenland’s ice sheet.
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