Antarctic geothermal heat flow and its implications for tectonics and ice sheets

Published online 26 October 2022Geothermal 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.Anya M. Reading, Tobias Stål, Jacqueline A. Halpin, Mareen Lösing, Jörg Ebbing, Weisen Shen, Felicity S. McCormack, Christine S. Siddoway, Derrick Hastero

Modelling the lithospheric rheology control on Cretaceous rifting in West Antarctica.

Small-scale analogue models were used to investigate the process of Cretaceous orthogonal extension in the West Antarctic Rift System. The models considered the transition from the East Antarctic Craton to a weaker lithosphere, and the results support previous hypotheses about the strong control exerted by lateral variations in lithospheric structures on the process of extension. Strain was mostly accommodated at the boundary between the two types of lithosphere, with a relative uplift of the cratonic block which remained essentially undeformed. Conversely, the weaker lithosphere showed wide-rifting style geometry, locally associated with core complex-like structures. In agreement with the natural prototype, this tectonic scenario led to a long-lasting extension without continental break-up, and to the absence of relevant surface magmatism. © 2007 Blackwell Publishing Ltd