Data from spacecraft along with Earth-based observations acquired over the past forty years have revealed many similarities among the four inner planets. It is generally accepted that Mercury, Venus, Earth, and Mars formed from accretion in the solar nebula based on their similar surface ages, densities and direction of revolution around the Sun. Because the net cooling of Earth is largely controlled by mantle convection, it is likely that mantle convection has also played a role in the thermal evolution of Mercury, Venus and Mars. There is implicit evidence for internal convection on Earth due to oceanic ridges and surface plate motions; however, it is difficult to determine whether the other inner planets experience or have experienced mantle convection. The assumption made by planetary scientists is that large terrestrial bodies containing concentrations of radiogenic heat sources comparable to that of Earth's must somehow transfer their internal heat to the crust in a similar fashion to Earth. Because heat escape likely drives thermal convection in the mantle, it is unlikely that mantle convection did not exist on the other terrestrial planets. Possible forms of convection on Mercury, Venus and Mars are mantle overturning event(s), small-scale convection, edge-driven convection, mantle plumes and localized impact induced convection.; In this research the possibility of convection on Mars and Mercury and its implication toward the thermal evolution of each planet is examined. In particular, the role of a mantle plume(s) in the formation of the Tharsis Rise, Mars and sluggish convection in a Mercurian mantle as a means to maintain a core dynamo are addressed. The planet Venus is more complicated due to high temperature and pressure at the surface. Mantle convection likely exists on Venus but the lack of plate tectonics prohibits efficient cooling of the mantle. Specific topics to address through thermal evolution modeling are the effect of high surface temperatures on mantle convection and whether dynamic processes from the mantle can support the observed high topography. Because 1D numerical models oversimplify the full equations of convectioe motion, this research uses 2D Cartesian, 2D spherical axisymmetric and 3D spherical geometries.
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