Effects of Sediment‐Laden Subglacial Discharge on Ice Shelf Basal Melting and Seabed Evolution

Abstract The grounding zone—where glaciers transition to floating ice shelves—critically influences ice sheet mass loss yet remains poorly observed. While tides and subglacial freshwater enhance basal melt, the role of sediment‐laden subglacial water outflow on ice shelf–ocean dynamics is unexplored. Using idealized ice shelf/ocean simulations that, for the first time, couple sediment transport with evolving bathymetry, we show that subglacial discharge increases melt rates by 88%, but suspended sediment within the cavity suppresses them by 1.9% in the cavity but by as much as 10% near the grounding line. Sediment increases seawater bulk density, slowing buoyant fluxes, and cavity circulation, while deposition forms a seabed high at the grounding line that reduces melt there by limiting relatively warm modified Circumpolar Deep Water intrusions from reaching the ice base. Depositional events in the grounding zone may contribute to grounding zone wedge (GZW) formation and the potential development of pinning‐points and grounding line advance that can impact ice sheet stability. New observations and multi‐decadal simulations using a coupled system model are required to further investigate the impacts on ice sheet stability.