Using large impacts to constrain the thermal evolution of the terrestrial planets

Padovan S, Tosi N, Plesa A-C, Ruedas T

Abstract

The surfaces of Mercury, the Moon, and Mars are largely the results of interior processes that operated over the age of the solar system. These surfaces are also the location of copious amount of data (e.g., imaging, spectrometry). However, the only direct constraints available when investigating the interior evolution of terrestrial planets are related to the nature (volcanic/primordial), volume, and age of the crust. In this work we compute thermal evolution models for Mercury, the Moon, and Mars constrained by the properties of their crusts. We evaluate the geodynamical effects of large impacts in the interior evolution of each body. We focus on reproducing the inferred volume and time of emplacement of the volcanic infillings associated with large impact basins. This approach combines local datasets with global thermal histories of the terrestr ial planets. We validate this method on Mercury by showing that we can reproduce the physical and spectral properties of its large basins. We apply the same methodology to Mars and the Moon.