Venus: A phase equilibria approach to model surface alteration as a function of rock composition, oxygen- and sulfur fugacities

Abstract

Venus: A phase equilibria approach to model surface alteration as a function of rock composition, oxygen-and sulfur fugacities. Icarus, 346, article no. 113779.For guidance on citations see FAQs.

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

“…The formation of these phases is further suggested by the oxygen fugacity models by Semprich et al. (2020) and suggested in other studies, but not observed on our samples (Berger et al., 2019; Fegley et al., 1992; Gilmore et al., 2017; Yu, 2007; 2018; Zolotov, 2015, 2018).…”

“…Pyrite (FeS 2 ), for example, was demonstrated to be unstable in the current Venus climate regime by , yet was and is considered as part of a possible climate model (Hashimoto & Abe, 2005;Klose et al, 1992;Wood, 1997). It is currently suggested that pyrite may be causing the radar anomaly that was first revealed in Venera radar data, and later observed in Magellan SAR data (Port et al, 2020;Schaefer & Fegley, 2004;Semprich et al, 2020).…”

Distinct Mineralogy and Age of Individual Lava Flows in Atla Regio, Venus Derived From Magellan Radar Emissivity

“…It is expected from theory that materials with high dielectric constants will enhance their radar reflectivity and lower their radar emissivity (Campbell, 1994; Pettengill et al., 1992). Proposed minerals include: (1) pyrite produced through sulfidation and/or oxidation of iron (Berger et al., 2019; Klose et al., 1992; Kohler, 2016; Pettengill et al., 1988; Port et al., 2016; Sempich et al., 2020; Wood & Brett, 1997), (2) coatings formed by condensation onto the rock as “metallic frosts” like lead and bismuth sulfides (Brackett et al., 1995; Kohler et al., 2015; Pettengill et al., 1996; Port et al., 2020; Schaefer & Fegley, 2004), and (3) ferroelectrics (e.g., perovskite or chlorapatite) that become highly conductive at certain temperatures (Arvidson et al., 1994; Shepard et al., 1994; Treiman et al., 2016). These reactions are a function of rock composition, atmospheric composition, temperature, and degree of weathering or surface age.…”

Extended Rift‐Associated Volcanism in Ganis Chasma, Venus Detected From Magellan Radar Emissivity

“…These radar “anomalies” are ascribed to the presence of minerals with a high dielectric constant, as it is expected from theory that materials with high dielectric constants will enhance their radar reflectivity and lower their radar emissivity (Campbell, 1994; Pettengill et al., 1992). Several studies indicate that high dielectric minerals can be produced through chemical weathering reactions between the rocks and the near‐surface atmosphere (e.g., Klose et al., 1992; Schaefer & Fegley, 2004; Semprich et al., 2020; Treiman et al., 2016 and references therein); if so, the reduction in radar emissivity can be associated with the formation of high dielectric minerals over time and thus can serve as a chronometer.…”