| Summary: | Geothermal heat flux (GHF) is a critical boundary condition that influences subglacial hydrology and the fast flow of the Antarctic ice sheet and is related to crustal and lithospheric architecture and composition. Despite its importance, Antarctic GHF heterogeneity remains poorly constrained and this hinders broader efforts to study solid earth influences on subice hydrology and ice sheet behaviour.Within the 4D Antarctica ESA project we produced a new continent-wide aeromagnetic anomaly compilation, conformed at longer wavelengths with SWARM satellite magnetic data and then applied Curie Depth Point (CDP) estimation approaches to provide new estimates of regional-scale GHF heterogenity beneath the West and East Antarctic ice sheets. Enhanced GHF is revealed beneath the most rapidly changing part of the West Antarctic Ice Sheet along the coast of the Amundsen Sea Embayment. It is inferred to arise from dynamic interactions between the West Antarctic Rift System and anomalously warm Pacific upper mantle underlying the thinned rifted lithosphere. Potential thermal anomalies are also detected beneath the Byrd Subglacial Basin between Thwaites and Pine Island glaciers, and several linear belts of enhanced GHF underlie the Siple Coast ice streams and associated active subglacial lake districts. In East Antarctica, intriguing regions of enhanced GHF are unveiled beneath the Dome C and Dome F lake districts. These may reflect either cryptic intraplate Mesozoic to Cenozoic fault reactivation and/or elevated intracrustal heat production in the inferred Proterozoic crust. Our CDP estimates provide further boundary conditions for the development of next-generation thermal models required to constrain regional GHF heterogeneity.
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