Thermochemical evolution of terrestrial planets: Earth, Mars, and the Moon

The thermal evolution of terrestrial planets controls processes from the surface (tectonics and volcanism) to the core (magnetic field generation) and may even be coupled to the evolution of planetary atmospheres and climates (with implications for liquid water on the surface and the evolution of life). This dissertation addresses three fundamental problems in thermochemical evolution of the terrestrial planets. First we consider the structure and composition of Earth's deep interior and address how the observed homogeneity of basalts erupted in world's ocean basins can be maintained, given what is known about mantle flow. Second, we address the question of how the Moon could have had an internally generated magnetic field suddenly 'switch-on' rather late in its evolution and then just as quickly 'switch-off'. Finally, we propose a new model for the genesis of the Tharsis plateau, the largest volcanic province in the solar system (which is on Mars), and do so without appealing to mantle plumes, the commonly attributed, yet problematic; origin for Tharsis. We simulate such processes in an appropriate geometry (3-D spherical) by using a finite-element method in conjunction with parallel computing.