Martian Mantle Heat Flow Estimate From the Lack of Lithospheric Flexure in the South Pole of Mars: Implications for Planetary Evolution and Basal Melting

Heat flow measurements are important for our understanding of planetary interior composition, structure, and evolution. In the absence of direct measurement, a first-order estimate of a planet's interior heat flow can be made by modeling the lithosphere's viscoelastic response to stress exerted by large surface loads. Here, we model the Martian lithosphere's viscoelastic response to the south polar layered deposits and estimate the local mantle heat flow to be less than ∼10 mW/m². Combined with our previous estimate of the low mantle heat flow from the north polar region (∼7 mW/m²), our results suggest that the Martian mantle may be globally depleted in heat-producing elements. The relatively low mantle heat flow has significant implications for Mars' long-term thermal evolution and on the possibility of basal melting in the south polar region.