Solid Planet–Atmosphere Interactions

Abstract

Planetary surfaces are coupled with planetary atmospheres through complex physical and chemical processes. On Mars and Venus, surface composition and climatic evolution are affected by volcanism, impacts, and atmosphere–surface interactions with limited and/or temporal influences from aqueous processes. Despite significant differences in environmental conditions on Mars and Venus, atmosphere–surface interactions reveal oxidation of surface materials by atmospheric gases and consumption of sulfur and halogens through weathering reactions. Atmosphere–surface interactions are altitude and latitude dependent owing to variations in surface temperature, pressure, and concentrations of atmospheric gases. On both planets, the composition of atmosphere and surface materials reveal past geological events, including intensive volcanic/impact degassing and resurfacing, as well as processes that occurred under wetter conditions. Although early atmospheric conditions could have favored formation of carbonates and hydrated minerals, current environments may not be feasible for carbonate formation.