¹G. Lopez-Reyes et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE008943]
¹ERICA Research Group and LaDIS. Universidad de Valladolid (Spain), Valladolid, Spain
Published by arrangement with John Wiley & Sons

The Mars 2020 Perseverance rover introduced Raman spectroscopy to in situ planetary exploration for the first time when it landed in Jezero crater on Mars in February 2021. The SuperCam instrument onboard Perseverance is a multi-analytical tool capable of acquiring time-resolved Raman data from Martian targets at standoff distances of a few meters. This is a particularly challenging task due to the operational constraints, the harsh conditions on the Martian surface, and especially the very fine-grained nature of the Martian soil. To address these challenges, the SuperCam Raman team has invested significant effort into optimizing both the acquisition and post-processing of Raman data collected on Mars, as detailed in this work. Additionally, this paper reviews and discusses the detections made by SuperCam Raman during the first 1,000 sols (almost 3 Earth years) of the Mars 2020 mission. During this period, SuperCam Raman data provided key insights into the mineralogy of Jezero throughout the Crater, Delta, and Margin Campaigns. Key detections include olivine, carbonates, perchlorates, and sulfates (such as anhydrite), identified in both abraded patches and natural surfaces. The high specificity of Raman spectroscopy enables the unequivocal identification of these minerals, allowing for rapid and direct interpretation of Jezero’s mineralogy, especially when combined with other techniques from SuperCam or others on the rover. Furthermore, this paper compiles the spectra acquired from the SuperCam Calibration Target samples on Mars, including studies on the degradation of the Ertalyte (PET), an organic polymer sample and analyses of diamond, apatite, and other reference materials.

¹Weronika Ofierska, ¹Max W. Schmidt, ¹Christian Liebske, ¹Paolo A. Sossi
Earth and Planetary Science Letters 673, 119691 (in Press) Open Access Link to Article [https://doi.org/10.1016/j.epsl.2025.119691]
¹Department of Earth and Planetary Science, ETH, Zürich, Switzerland
Copyright Elsevier

Owing to the incompatibility of K, rare-earth elements (REE) and P in silicate minerals relative to melt, the KREEP component, found on the near-side of the Moon, is thought to have formed through protracted crystallisation of the Lunar Magma Ocean (LMO). Our fractional crystallisation experiments simulate the final stages of LMO crystallisation, from plagioclase onset to the last eutectic melt remnants. Results show the LMO liquid to remain saturated in olivine ± orthopyroxene ± Cr-spinel up to 74 % solidification (PCS), transitioning to plagioclase+clinopyroxene (cpx) from 1200 °C (74 PCS) to 1120 °C (88 PCS). The plagioclase+cpx+quartz cotectic is reached at 1080 °C (92.3 PCS), with liquid immiscibility and a crystal assemblage of plagioclase+augite+Ti-spinel+ilmenite+quartz occurring at 1030 °C (98.8 PCS), until nearly complete crystallization is reached at 1000 °C (99.5 PCS). Mineral/melt (plagioclase, pigeonite, high-Ca cpx) and melt/melt partition coefficients for K, REE, P, Zr, Hf, Nb, Th, and U were determined. They are used to model melt evolution to 99.5 PCS, showing that fractional crystallisation alone replicates KREEP’s REE profile and the above trace elements, yet, distinct Lu/Hf (and U/Pb) ratios suggest additional processes. Assuming a finite oxygen budget in the LMO and incompatible behaviour of Fe3+, the Eu anomaly of KREEP is best reproduced by a model in which oxygen fugacity (
) evolves from one log unit below to 1.5 log units above the iron-wustite buffer (IW-1 to IW+1.5) from 0 PCS to 99.4 PCS. Minor dacitic melt separation (1–5 % of the melt remaining at 1030 °C) sequestering K from REE+P is consistent with but unnecessary for KREEP formation; nevertheless, a second-stage partial re-melting of these dacites could match observed FeO and incompatible element abundances of lunar granites.