¹José San Martin et al. (>10)
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2024.116403]
¹Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany
Copyright Elsevier

Martian Simulants are an essential part of in situ resource utilization (ISRU) technology development and testing, and aid in providing new astrobiology insights regarding Mars’s past habitability. This study proposes a new method involving average and standard deviation (ASD), complementary to Figures of Merit (FOM) simulant evaluation methods, for geochemical prospection and evaluation of simulant feedstock using portable XRF (pXRF) and whole-rock (ICP-OES) analyses. It also presents Simulant Modification Calculations (SMC) that integrate multiple approaches used in simulant production and design, and provides theoretical mineral recipes (estimated mineral composition) and their estimated geochemical compositions for FOM evaluation of an intended target composition. These methods were used to prospect simulant material in volcanic-subvolcanic outcrops at the SW edge of the Atacama Desert in Chile, and to evaluate their potential for standard and enhanced simulant development. Through ASD (pXRF data) and FOM (ICP-OES data) evaluation, this resulted in the presentation of the first Chilean basic Martian bedrock simulant that can be used for Biomining applications, which is tentatively labeled as Chilean Atacama Desert 1 (CAD-1). An Excel file with the applied prospection method and database is also available for simulant feedstock prospection (Supplementary section). Applying these methods will provide more base materials and components for simulant development and allow flexibility in their design for general and specific applications.

¹C. H. Seeger,¹J. P. Grotzinger
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008531]
¹Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
Published by arrangement with John Wiley & Sons

The diversity and abundance of diagenetic textures observed in sedimentary rocks of the clay-sulfate transition recorded in the stratigraphic record of Gale crater are distinctive within the rover’s traverse. This study catalogs all textures observed by the MAHLI instrument, including their abundances, morphologies, and cross-cutting relationships in order to suggest a paragenetic sequence in which multiple episodes of diagenetic fluid flow were required to form co-occurring color variations, pits, and nodules; secondary nodule populations; and two generations of Ca sulfate fracture-filling vein precipitation. Spatial heterogeneities in the abundance and diversity of these textures throughout the studied stratigraphic section loosely correlate with stratigraphic unit, suggesting that grain size and compaction controls on fluid pathways influenced their formation; these patterns are especially prevalent in the Pontours member, where primary stratigraphy is entirely overprinted by a nodular fabric, and the base of the stratigraphic section, where increased textural diversity may be influenced by the underlying less permeable clay-bearing rocks of the Glen Torridon region. Correlations between quantitative nodule abundance and subtle variations in measured bulk rock chemistry (especially MgO and SO3 enrichment) by the Alpha Particle X-Ray Spectrometer instrument suggest that an increase in Mg sulfate upsection is linked to precipitation of pore-filling diagenetic cement. Due to a lack of sedimentological evidence for widespread evaporite or near-surface crust formation of these Mg sulfates, we propose three alternative hypotheses for subsurface groundwater-related remobilization of pre-existing sulfates and reprecipitation at depth in pore spaces.