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201 records · Page 12

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NASA NTRSDate not supplied

Carbon Limited Soils of Iceland: Analogs for Identifying Carbon-Mineral Interactions in Gale Crater, Mars Surface Materials

The Mars Science Laboratory’s Curiosity rover mission to Gale Crater, Mars has a goal to search for organic carbon and corresponding evidence of ancient microbiology preserved in clay mineral-rich sedimentary deposits [1]. No clear correlation of clay mineral (smectite) abundances with the Sample Analysis at Mars (SAM) carbon detections (up to 2000 ppm C) [2] has been established, suggesting other phases may preserve organic C in martian sediments. Terrestrial volcanic glass soils can accumulate C due to the C-complexing abilities of poorly crystalline Al- and Fe-oxyhydroxides [3]. The Xray amorphous component (20 to 73 wt. %) in Gale Crater materials [4,5] has received little consideration regarding organic C preservation in Gale Crater. The objectives of this work are to 1) Evaluate C content and level of soil development of basaltic glass-bearing Icelandic soils to determine the role that poorly crystalline phases have in complexing organic C in carbon limited soils and 2) Determine if evolved gas analysis (EGA) of well-characterized Mars analog basaltic materials from Iceland can be used to interpret SAM data to understand the nature of organic-C mineral/geochemical associations in Gale materials.

B. Sutter↗

NASA NTRSDate not supplied

Mineral composition of Al-rich float rocks in Jezero crater as seen by Super-Cam

During its traverse across the Jezero crater floor and western fan, the Perseverance rover encountered > 4000 float rocks – of variable size (up to ~ 50 cm) scattered on the ground without apparent connection to the surrounding stratigraphy [1]. Analysis performed using the SuperCam instrument’s [2,3,4], Laser Induced Breakdown Spectroscopy (LIBS) revealed a high concentration of Al 2 O 3 , Cr, Ti and Ni [5], and very low of Fe, Mg, Ca and Na [5, 1]. SuperCam’s infrared reflectance spectroscopy (IRS, between 1.3 and 2.6 μm) showed the presence of Al-rich aqueous alteration minerals (characteristic absorption bands of kaolinite and Al-smectites at 1.4 and 2.2 μm) as well as some (likely Cr-) spinels, identified uthrough their broad asymmetric 2 μm band, responsible for the concavity of IR spectra. These mineral species alone do not fully account for the spectral shapes; hence, the objective is to further investigate spectral modeling to determine the most probable mineral assemblages. Here, we present the results of modeling 17 light-toned float rocks, up to Sol 924, complementary to [1].

C. Royer↗

NASA NTRS2024

Hydrogen Isotopic Composition of Hydrous Minerals in Particles From Bennu

On September 24, 2023, NASA’s OSIRIS-REx mission delivered to Earth ~121 g of pristine carbonaceous regolith from asteroid Bennu. A first series of mineralogical observations and chemical/isotopic analyses of Bennu aggregate samples (fine to coarse particles up to a few mm) revealed that this material resembles the most chemically primitive chondrites and the samples returned by the JAXA’s Hayabusa2 mission from the carbonaceous asteroid Ryugu. Laboratory studies have confirmed the story gleaned from the spacecraft encounter that Bennu’s rock fragments underwent extensive aqueous alteration and are predominantly composed of hydrated minerals (serpentine, smectite) and other secondary minerals (e.g., magnetite, carbonates). The secondary phases were likely formed under the presence of liquid water on Bennu’s parent asteroid. The isotopic compositions of hydrous minerals and secondary phases can increase our understanding of the source and distribution of water and volatile elements in the protoplanetary disk [e.g., 5-8]. However, direct estimates of the hydrogen isotopic ratios (D/H) in hydrous minerals cannot be obtained easily in primitive rocks due to the difficulty in estimating the organic matter (OM) contribution to the whole H budget. In order to obtain hints on the initial constituents of Bennu’s parent asteroid and to test if Bennu's parent asteroid have formed beyond the snow line (hypothesis 4 of [9]), we measured the D/H and C/H ratios in chondritic matrices by secondary ion mass spectrometry (SIMS) and obtain information on the D/H ratio of water retained in the hydrated minerals. The method also gives clues on the hydrogen isotope variability among different Bennu rock fragments made available for measurement.

L Piani↗