^1,2Camilla Cioria,^1,2Giuseppe Mitri,³James Alexander Denis Connolly,⁴Jean-Philippe Perrillat,⁵Fabrizio Saracino
Journal of Geophysical Research (Planets) Link to Article [https://doi.org/10.1029/2023JE008234]
¹International Research School of Planetary Sciences, Università d’Annunzio, Pescara, Italy
²Dipartimento di Ingegneria e Geologia, Università d’Annunzio, Pescara, Italy
³Department of Earth Sciences, Institute for Geochemistry and Petrology, ETH Zürich, Zürich, Switzerland
⁴Laboratoire de Géologie de Lyon, CNRS, Université de Lyon, Université Lyon 1, Ens de Lyon, Villeurbanne, France
⁵Department of Geology, University of Liège, Liège, Belgium
Published by arrangement with John Wiley & Sons

The mineralogy of planetary mantles formed under reducing conditions, as documented in the inner regions of the solar system, is not well constrained. We present thermodynamic models of mineral assemblages that would constitute the mantles of exo-Mercuries. We investigated reduced materials such as enstatite chondrites, CH, and CB chondrites, and aubrites, as precursor bulk compositions in phase equilibrium modeling. The resulting isochemical phase diagram sections indicate that dominant phases in these reduced mantles would be pyroxenes rather than olivine, contrasting with the olivine-rich mantles found within Earth, Mars, and Venus. The pyroxene abundances in the modeled mantles assemblages depend on the silica content shown by precursor materials. The silica abundance in the mantle is closely related to Si abundance in the core, particularly in reduced environments. In addition, we propose that pyroxene-rich mantles exhibit more vigorous convective and tectonic activity than olivine-rich mantles, given that pyroxene-rich mantles would have lower viscosity and a lower solidus temperature (Ts).