Experimental weathering of rocks and minerals at Venus conditions in the Glenn Extreme Environments Rig (GEER)

1,2Alison R. Santos,1Martha S. Gilmore,1James P. Greenwood,3 Leah M. Nakley,3,4Kyle Phillips,3Tibor Kremic,1Xavier Lopez
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2022JE007423]
1Department of Earth and Environmental Sciences, Wesleyan University, 265 Church St., Middletown, CT, 06459 United States
2Previously at: NASA Postdoctoral Program Fellow, NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, OH 44135
3NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, OH, 44135 United States
4Previously at: HX5 Sierra, LLC, 21000 Brookpark Rd., Cleveland, OH 44135.
Published by arrangement with John Wiley & Sons

We report two experiments using 13 mineral and rock samples exposed to a complex synthetic Venus atmosphere composed of nine gases for durations of 30 and 11 days conducted using the NASA Glenn Extreme Environment Rig (GEER). Examination of our run products using a scanning electron microscope equipped with an energy dispersive spectrometer reveals secondary minerals predominantly formed from reactions of Fe and Ca in the solid samples with sulfur in the atmospheric gas, results largely predicted in the literature, and indicating that such reactions between rocks and the atmosphere at the Venus surface may occur rapidly. Samples that displayed larger degrees of reaction include calcite (forming Ca-sulfate), Fe-Ti oxide (forming an Fe,S phase), biotite (forming an Fe,S phase), chalcopyrite (forming a new Cu,Fe-sulfide and a Ag,Cl phase), and Mid-Ocean Ridge Basalt glass (forming a Ca- and S-bearing phase, Fe- and S-bearing phase, and an Fe-oxide); pyrite was observed to be stable in our 30-day experiment. These reactions indicate that the fS2 of the experiments was above or at the high end of what is thermodynamically predicted for the Venus surface. Apatite, feldspars, actinolite, and quartz did not change in this time frame. The presence of multiple S species in GEER may explain dissimilarities in the style of reactions seen in previous experiments with simpler gas mixtures.


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