VenusVolAtmos · Volatile Element Cycles on Venus: Implications for the Evolution of Venus´ Greenhouse-Dominated Atmosphere

Venus is similar to Earth in terms of density, size and composition. Yet both bodies evolved so dramatically different that Venus now has an uninhabitable, run-away greenhouse atmosphere in contrast to Earth ́s favourable habitable conditions. Despite alarming parallels with CO2-driven global warming on Earth, the origin and evolution of Venus ́ run-away greenhouse atmosphere remains poorly understood. Problematically, current models fail to incorporate the important effects of volcanic degassing and atmosphere-surface interaction throughout Venus ́ history. Due to Venus’ CO2-rich atmosphere, surface pressures are 90 times greater than on Earth. Volcanoes on Venus will degas under very different conditions, yielding different volcanic gas compositions and gas fluxes to the atmosphere. Constraints on volatility and the contribution of magmatic volatiles to the composition of Venus ́ atmosphere are pivotal for understanding the extent and timing of volcanic activity on Venus, especially in light of upcoming Venus exploration missions. Interaction between Venus’ atmosphere, volcanic gasses and surface likely plays a key role in determining volatile fluxes but is poorly understood at conditions relevant for Venus’ surface. The critical lack of such challenging experiments precludes a detailed assessment of the Venusian volatile cycle and atmospheric evolution.I will quantify the past and current interior-to-atmosphere volatile element flux on Venus. In a highly multi-disciplinary approach I will perform 1) pioneering, high P-T experiments mimicking magma degassing on Venus and atmosphere-gas-rock interactions, 2) using state-of-the-art (in situ) analyses of gas speciation and reaction rates and 3) integrate these results in numerical models to obtain quantitative volatile fluxes for Venus. This work allows for rigorous re-assessment of Venus’ interior and atmospheric evolution and will provide a solid framework for future exploration of Venus.