Constraints on the radiogenic heat production rate in the Martian interior from viscous relaxation of crustal

Kurzfassung

Crustal thickness variations induce lateral pressure gradients which can drive flow in the lower crust if temperatures there are sufficiently high. The absence of large scale crustal relaxation at the Argyre impact basin therefore constrains the temperatures at the base of the crust and we have computed thermal evolution models to study the influence of radiogenic heating and hydrothermal crustal cooling on lower crustal temperatures. In the presence and absence of hydrothermal crustal cooling and for an average crustal thickness of 45 km, radiogenic heating after core formation cannot have exceeded 58 and 43 pW kg⁻¹, respectively. Furthermore, if the average crustal thickness is closer to 50 km, heating cannot have exceeded 49 and 36 pW kg⁻¹. A better knowledge of the planet's average crustal thickness, which may be obtained from seismological experiments, could help to further constrain the planets bulk composition and even rule out some of the compositional models for Mars that have been proposed so far.