Thermodynamics of Element Volatility and its Application to Planetary Processes

Abstract

Despite its importance in geological sciences, our understanding of interactions between gas and condensed phases (comprising solids and liquids) remains clouded by the fact that, often, only indirect evidence remains for their occurrence. This arises from the tendency for the vapour phase to escape from the condensed phase with which it interacts, owing to its much lower density and thus greater volume. For a gas that is sufficiently tenuous that interactions do not occur between its constituent molecules, this relationship is quantified in the ideal gas law (Clapeyron 1834): $PV=nRT$ (1) where $P$ is the total pressure exerted by the gas, $V$ its volume, $n$ is the number of moles, $R$ the gas constant 8.3145 $Jmo{l}^{-1}{K}^{-1}$, Horstmann, 1873) and $T$ the absolute temperature. One mole of an ideal gas at 273.15 $K$ and $10^5$ $Pa$ (standard temperature and pressure for gases) has a molar volume of 22,711 $c{m}^3/mol$, $10^3$ x greater than typical silicate liquids or minerals. As a result, vaporisation processes in nature are often informed by chemical and textural evidence remaining in the condensed phase.

95 pages 19 figures 5 tables

References in corpus (8)

• Chemistry of Silicate Atmospheres of Evaporating Super-Earths
• A perspective from extinct radionuclides on a Young Stellar Object: The Sun and its accretion disk
• Lunar and Terrestrial Planet Formation in the Grand Tack Scenario
• The structure of terrestrial bodies: Impact heating, corotation limits and synestias
• Inefficient volatile loss from the Moon-forming disk: reconciling the giant impact hypothesis and a wet Moon
• The Solar Argon Abundance
• Collisional stripping of planetary crusts
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Cited by in corpus (6)

• Loss and fractionation of noble gas isotopes and moderately volatile elements from planetary embryos and early Venus, Earth and Mars
• Stochastic accretion of the Earth
• Mineral Processing and Metal Extraction on the Lunar Surface -- Challenges and Opportunities
• Composition of Terrestrial Exoplanet Atmospheres from Meteorite Outgassing Experiments
• Volatility of Sodium in Carbonaceous Chondrites at Temperatures Consistent with Low-Perihelia Asteroids
• Evidence for post-nebula volatilisation in an exo-planetary body