Martian thermal history, core segregation, and tectonics

A series of calculated thermal histories of Mars is presented, and their possible relation to surface tectonic history is discussed. The models include convective heat transport through an empirical approximation, and heating by radioactivity and core segregation. Initial temperature and the timing and duration of core segregation are treated as free parameters. The initial temperature is the main determinant of Martian thermal evolution: as it is varied from 20 to 100% of the present mean temperature, the maximum in surface heat flux moves from very recent to very early in Martian history. For the latter cases, the details of core segregation control the detailed timing of a peak in the thermal flux that exceeded 100 mW/sq m. It is suggested that the early disruption of cratered terrain crust in the northern hemisphere and subsequent volcanic resurfacing may have been related to core segregation. This would be consistent with a scenario in which an early period of core segregation generated a marked peak in the thermal flux that may have led to extensive partial melting and volcanism. This scenario would require Mars to have had an initial mean temperature comparable to the present value.