What Can Terrestrial Sand-Textured Soils Reveal About the Composition of Core Materials Forming Martian Regolithƒ

Abstract

Reliable interpretations of remote sensing data obtained from Mars, notably in the visible and near-infrared spectral domains, need to correctly account for variations on the reflectance of the sand-textured regolith covering its surface. These variations, in turn, are directly associated not only with the presence of iron oxides, which are also found in dune fields and coastal landscapes on Earth, but also with the composition of the core (parent) material forming different types of Martian regolith. While the core materials of terrestrial sand-textured soils can be clearly identified, the same cannot be said about the core materials of Martian regolith. The difficulties to solve this open question are mainly prompted by the relatively restricted range of experiments that can be performed using equipment deployed on Mars. In fact, missions have been proposed to overcome these restrictions by collecting and bringing samples of Martian soils to Earth. In the meantime, the pairing of remote sensing technology with in silico experiments continues to play a key role in investigations of Martian geomorphology, mineralogy and weathering history. Following this trend, we have compared the effects of different types of core materials on the reflectance of Martian regolith in order to add to the current knowledge about its composition. The core material candidates were selected based on remote and in situ observations of terrestrial and Martian sand-textured soils. Our in silico experiments were performed using a first-principles simulation framework in conjunction with measured reflectance data obtained from different regions on Mars. Besides contributing to the elucidation of the problem at hand, our findings enable an original and predictive assessment of the impact of different core materials on the spectral signatures of terrestrial and non-terrestrial sand-textured soils.