Experiments on the reactivity of basaltic minerals and glasses in Venus surface conditions using the Glenn Extreme Environment Rig

Abstract

Climate models for Venus rely heavily on theoretical modeling and laboratory experimentation due to the extreme surface conditions of the planet and limited in situ surface data. To better explore the relative importance of reactions between the surface and the atmosphere on Venus, we exposed representative volcanic glasses and basaltic minerals to a large-scale simulation of Venus surface conditions with a realistic atmospheric composition. This study consistend of two experiments of 42 and 80 days that replicated both physical conditions and atmosphere composition derived from available in situ near-surface data using the Glenn Extreme Environment Rig (GEER) at the NASA Glenn Research Center. These experiments revealed significant reactivity of common Ca-bearing pyroxenes (diopside and augite) to form anhydrite. Olivine and labradorite showed minimal reactivity. Volcanic glasses, including both natural and synthetic samples, were exceptionally reactive, rapidly forming both anhydrite and thénardite (Na2SO4), as well as transition metal sulfates (i.e., Cu, Cr), halite (NaCl), and sylvite (KCl). Our results document chemical and textural alteration of sample surfaces and provide sufficient evidence for an active sulfur sink on multiple samples, with sulfates as the dominant secondary mineralogy. These experiments suggest likely surface mineralogies and solid phases present on Venus' surface with significant implications for upcoming missions and provide new data for comparison to high-temperature mineral–gas reactions prevalent on Venus, Earth, and Io.