^1,2John Carter,³Lucie Riu,¹François Poulet,¹Jean-Pierre Bibring,¹Yves Langevin,¹Brigitte Gondet
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2022.115164]
¹Institut d’Astrophysique Spatiale (IAS), CNRS/Paris-Saclay University, France
²Laboratoire d’Astrophysique de Marseille (LAM), CNRS/Aix-Marseille University, France
³ESA-ESAC, Madrid, Spain
Copyright Elsevier

We describe the completion of the MOCAAS project providing a global repository of secondary minerals formed through interaction with water on Mars. This work is based on the analysis of orbital imaging spectroscopy data from the OMEGA/Mars Express and CRISM/MRO near-infrared instruments. A database and a set of high-resolution global maps (200 m/pix) are produced which provide a large collection of these “aqueous” secondary mineral deposits, most of which were not previously reported. Several aqueous mineral classes are discriminated including hydrated silicates, hydrated silica, sulfate and carbonate salts. A preliminary statistical analysis on the database of aqueous mineral deposits is carried out, revealing significantly more widespread and diverse aqueous alteration on Noachian and Hesperian Mars than previously seen. Higher resolution local scale studies are also carried out over current and prospective rover landing sites on Mars, providing enhanced sensitivity to mineral detection and reachable science targets. Collectively, the data presented here at all scales is expected to foster synergy between orbital and landed missions, particularly for future missions and to pinpoint prospective resources for human exploration.

¹Alessandro Pisello,²Marco Ferrari,²Simone De Angelis,^1,2,3Francesco P.Vetere,¹Massimiliano Porreca,²Stefania Stefani,¹Diego Perugini
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2022.115222]
¹Department of Physics and Geology, University of Perugia, I-06123 Perugia, Italy
²Institute for Space Astrophysics and Planetology, INAF, Rome, Italy
³Department of Physical Sciences, Earth and Environment, University of Siena, 53100, Italy
Copyright Elsevier

Volcanic phenomaena shaped the surface of all terrestrial planets in the solar system, and silicate glasses represent a major component in pyroclastic deposits and lavas. Spectral features of silicate glasses therefore influence spectral characteristics of large portions of planetary surfaces.

In this study, experimental petrology techniques have been used to produce 19 silicate glass samples having natural chemical composition corresponding to four of the most common magmatic series on planet Earth. Reflectance of such products was investigated in the mid-infrared region (MIR) to observe the evolution of their spectral characteristics with changing degree of evolution (expressed as silica content) and alkaline content. We have observed how chemical features have a clear influence in shifting the spectral features (to lower wavelengths with increasing silica, such as for previously studied volcanic rocks) and on the spectral shape, which is substantially different between mafic and highly silicic products. This allowed us to propose a model to retrieve chemical information (SiO2 and SiO2 + Al2O3 + TiO2 content) from the wavelength at which spectral features (CF and RBpeak) occur. Moreover, by comparing our results with previous MIR studies we have observed that our model can be applied, to a certain extent, to interpret chemical fingerpint volcanic rocks in general. Here, it is also shown how granulometry influences spectral shape, but does not affect spectral shift.

This study will be useful to interpret planetary information and assess how amorphous silicate phases influence spectral characteristics of volcanic areas on planetary surfaces.