A New Seismology-Derived Geothermal Heat Flux Map and Its Tectonic Implications

Abstract:

The geothermal heat flux (GHF) is an important boundary condition for modeling the movement of the Antarctic ice sheet but is difficult to measure systematically at a continental scale. Earlier GHF maps suffer from low resolution and possibly biased assumptions in tectonism and crustal heat generation, resulting in significant uncertainty. Empirically relating the upper mantle structure of Antarctica to other areas with well-constrained lithosphere structure and well-measured GHF has been used to constrain the Antarctica GHF, but with lower resolution and high uncertainties. In this presentation, we show a new GHF map for Antarctica constructed by using the latest published high-resolution seismic model. Combined from a full-wave inverted model that covers the whole continent and a regional Monte-Carlo derived high-resolution model that quantifies its uncertainties, the new seismic model allows us to produce a high resolution GHF map from the known GHF in the continental United States. The new map, compared with previously seismologically determined one, has improved resolution and lower uncertainties. New features in this map include high GHF in the southern Transantarctic Mountains where warmer uppermost mantle is introduced by lithospheric removal and in the Thwaites Glacier region. Notably, we also identify a modest GHF in the central West Antarctic Rift system near the Siple Coast and an absence of large‐scale regions with GHF greater than 90 mW/m² are found. Additional notes on the tectonic origin of these variations based on a thermodynamic inversion of seismic data are also discussed.