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Geothermal heat flow (GHF) is an elusive physical property, yet it can reveal past and present plate tectonic processes. In Antarctica, GHF has further consequences in predicting the response of ice sheets to climate change. In this Review, we discuss variations in Antarctic GHF models based on geophysical methods and draw insights into tectonics and GHF model usage for ice sheet modelling. The inferred GHF at continental scale for West Antarctica (up to 119 mW m−2, 95th percentile) points to numerous contributing influences, including non- steady state neotectonic processes. Combined influences cause especially high values in the vicinity of the Thwaites Glacier, a location critical for the accurate prediction of accelerated loss of Antarctic ice mass. The inferred variations across East Antarctica are more subtle (up to 66 mW m−2, 95th percentile), where slightly elevated values in some locations correspond to the influence of thinned lithosphere and tectonic units with concentrations of heat- producing elements. Fine- scale anomalies owing to heat- producing elements and horizontal components of heat flow are important for regional modelling. GHF maps comprising central values with these fine- scale anomalies captured within uncertainty bounds can thus enable improved ensemble- based ice sheet model predictions of Antarctic ice loss. 

An accurate viscosity structure is critical to truthfully modeling lithosphere dynamics. Here, we report an attempt to infer the effective lithospheric viscosity from a high-resolution magnetotelluric (MT) survey across the western United States. The high sensitivity of MT fields to the presence of electrically conductive fluids makes it a promising proxy for determining mechanical strength variations throughout the lithosphere. We demonstrate how a viscosity structure, approximated from electrical resistivity, results in a geodynamic model that successfully predicts short-wavelength surface topography, lithospheric deformation, and mantle upwelling beneath recent volcanism. We further show that this viscosity is physically consistent with and better constrained than that derived from laboratory-based rheology. We conclude that MT imaging provides a practical observational constraint for quantifying the dynamic evolution of the continental lithosphere.