Abstract The deep interior of the East Antarctic Ice sheet likely contains important records of climate and ice sheet evolution. Here we report on a recent aerogeophysical survey of the southern flank of Dome A, over South Pole Basin. We find an extensive radioglaciologically defined basal unit under Dome A that abruptly truncates within South Pole Basin. This truncation aligns with a change of subglacial bed properties and distinct subglacial landforms. We infer that this basal unit may be slowly transporting and depositing material through local basal melting in South Pole Basin into an extensive, subglacially forming, sedimentary basin. In turn, this sedimentary basin may induce locally enhanced melting by hosting local groundwater.