Antarctic geothermal heat flux: past, present and future perspectives

Geothermal Heat Flux (GHF) measurements and estimates of GHF via geophysical and thermal modelling are required to better predict past, present and future Antarctic ice sheet behaviour, including its dynamic responses to ocean and climate warming. In addition to its relevance for modelling subglacial hydrology and ice sheet dynamics, including e.g. the onset and maintenance of enhanced glacial flow, GHF serves as a boundary condition for paleotopography and paleoclimate studies (in particular for deep ice core drilling site selection), and is also important as both an indicator and an influence on the tectono-thermal evolution of the lithosphere.

Despite its pivotal importance, there is still a paucity of direct Antarctic GHF measurements. Consequently, geophysical estimates derived from seismology, satellite-magnetic and aeromagnetic data, and sparse MT, provide in many regions the only available constraints on the potential degree of spatial variability in GHF for much of the continent. In spite of some commonality, there are major differences in the currently available geophysical estimates of GHF, and this adds uncertainty to coupled ice sheet and Solid Earth studies (including GIA), as well as hampering our understanding of the Antarctic lithosphere and its tectono-thermal evolution. For example, some models predict high GHF in the interior of the West Antarctic Rift System (WARS), beneath parts of the West Antarctic Ice Sheet, while others favour instead higher GHF beneath the Marie Byrd Land dome (where a potential hot spot is located) and along the western edge of the WARS and beneath some parts of the Transantarctic Mountains front (where lithosphere delamination may also have occurred).

Reconciling these differences is imperative if we are to understand the tectono-thermal processes that affected the WARS and ultimately its current state, and subsequently assess its influence on several highly dynamic and potentially unstable sectors of the WAIS, including in particular the Amundsen Sea Embayment. Equally important, is getting a better handle on the regional and more local-scale variability with respect to the generally lower background values of the composite East Antarctic craton. This includes assessing intra-crustal GHF variations linked to its different cratons and orogenic belts and their overlying basins (e.g. Wilkes, Aurora, Recovery and Pensacola-Pole basins) that have recently received heightened international attention because of their influence on the stability of the East Antarctic Ice Sheet.