¹N. Zimmermann,¹M. Safari,¹H. Nekvasil
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [ https://doi.org/10.1029/2024JE008906]
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008906]
¹Department of Geosciences, Stony Brook University, Stony Brook, NY, USA
Published by arrangement with John Wiley & Sons

Martian magmas compositionally resemble those from terrestrial continental hotspot magmatic suites, characterized by low OH and high Cl and S contents. The magmatic gases exsolved from such magmas transport a variety of metal complexes and, upon cooling, precipitate vapor-deposits into vugs and fractures within rocks and on the surfaces of pyroclastics, which are then added to surface fines. Experiments investigated trace element behavior during magmatic degassing as a potential signature of this magmatic process. Low-pressure experimental degassing of P-rich basaltic magma containing Cl, Br, S, minor OH, and trace elements (Sr, Ge, Ga, Zn, Pb, Rb, Cs, Se, Cu, La, and Lu) demonstrated that the gas-transported trace metals become incorporated into vapor-deposited Cs-Pb-Zn-Rb-bearing halides, Ge-Ga-bearing iron oxides, Zn-Se-Cu-bearing sulfides, alkali and iron sulfates, Ge-bearing silicates, rare earth phosphates, and elemental metals. Low-OH and high-Cl magmatic systems produce a variety of halides but inhibit Fe-oxide formation. S-rich systems produce vapor-deposited Na-, K-, and Fe-sulfates, Zn-Cu-Se bearing sulfides, and iron oxides. These results provide a signature for determining the possibility of a significant role for magmatic gas in producing secondary minerals and volatile trace element enrichment in the Gusev plains, Columbia Hills, Jezero crater, and Gale crater. A hallmark of vapor-deposited phases is the presence of local heterogeneities in “alteration” phases and in trace element signatures due to the superposition of high and low temperature phases.

¹E. Caminiti,²S. Besse,³A. Doressoundiram,^4,5J. Wright
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE009359]
¹Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan
²European Space Agency (ESA), European Space Astronomy Center (ESAC), Madrid, Spain
³LIRA, Observatoire deParis, Université PSL, CNRS, Sorbone Université, Université de Paris, Meudon, France
⁴School of Physics and Astronomy, University of Leicester, Leicester, UK,
⁵School of Physical Sciences, The Open University, Milton Keynes, UK
Published by arrangement with John Wiley & Sons

NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging mission hasrevealed that about 27% of the surface of Mercury is covered by smooth plains, which are mostly volcanic inorigin. These plains are mainly located in the northern hemisphere, as well as within and around majorimpact basins. We used Mercury Atmospheric and Surface Composition Spectrometer data to perform anexhaustive spectral analysis of five major impact basins: Caloris, Rembrandt, Beethoven, Tolstoj, andRachmaninoff. We highlighted the existence of a new high‐reflectance spectral unit, that had previously onlybeen identified within the Rembrandt basin, as a major unit being more widespread. We named this new unitYoung High‐reflectance Red Plains. We found a common sequence of volcanic episodes that infilled thebasins and shaped their current surface spectral properties. We have shown that the size of the basin and theage of the volcanic infills are likely important parameters for the layering of different volcanic plains,defining the surface spectral units. Our study gives access to mantle properties, and we suggest thatheterogeneity in the mantle is certainly not necessary to explain the spectral properties of effusive volcanismassociated with impact basins. Future observations by the ESA‐JAXA‐BepiColombo mission are eagerlyawaited to better constrain the planet’s spectral, compositional, morphological, and geophysical surfaceproperties.