a Geothermal heat flow distribution with areas of magnetic data gaps and those with MF7 magnetic data coverage (https://www.geomag.us/models/MF7.html) shown in gray. White dashed lines mark location of glaciers: PIG Pine Island glacier, THW Thwaites glacier, PG Pope glacier. b Lithospheric effective elastic thickness29 and the visco-elastic response32. White dashed lines show area of Byrd subglacial basin (BSB) and Bentley subglacial trough (BST). c Compilation of continental-wide6 and local in-situ estimates of geothermal heat flow15,16,34,35. d Tectonic features of the study region. The high geothermal heat flow region (A) is surrounded by the Thurston Island Block (TIB), Ellsworth–Whitmore Mountain (EWM) block and Marie Byrd Land (MBL). The Mount Murphy Rift (MMR)54 correlates with a suite of NNE–SSW trending magnetic lineaments (marked with white lines). The Pine Island rift (PIR) is shown as part of the Thurston Island block.