¹Alexandre V. Andronikov,¹Irina E. Andronikova,¹Ondrej Pour,¹Petr Bohdalek
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14347]
¹Division of Geochemistry and Laboratories, Czech Geological Survey, Prague, Czech Republic
Published by arrangement with John Wiley & Sons

We have analyzed in situ mineral phases in a Potůčky fragment of the stony-iron IVA-an meteorite Steinbach for trace-element compositions. The studied fragment contains silicate grains (pyroxene and tridymite) interspersed with grains of metal (kamacite, plessite, and taenite) displaying Widmanstätten pattern and troilite. Multiple inclusions of chromite, troilite, and bi-mineral troilite + taenite assemblages were observed within some pyroxene grains. The data on variations in trace-element compositions in different meteorite phases are consistent with a number of models, suggesting the involvement of several processes in the generation of the lithologies presently observed in the Potůčky meteorite. These processes might have involved fractional crystallization of silicate liquid, collision, impact, shock melting, and cooling. As a result of such processes, specific trace-element composition of different mineral phases was formed. Trace-element compositions of metals and sulfides from the Potůčky meteorite are very similar to those for minerals from the LL ordinary chondrite, suggesting LL-like asteroid as a parent body for the Potůčky (IVA-an) precursor material.

¹Carole Freissinet et al. (>10)
Proceedings of the National Academy of Science of the USA (PNAS) 122, e2420580122 Open Access Link to Article [https://doi.org/10.1073/pnas.2420580122]

¹Laboratoire Atmosphères et Observations Spatiales, Université Versailles St Quentin Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt 78280, France

Organic molecules preserved in ancient Martian rocks provide a critical record of the past habitability of Mars and could be chemical biosignatures. Experiments conducted by the Sample Analysis at Mars instrument onboard the Curiosity rover have previously reported several classes of indigenous chlorinated and sulfur-containing organic compounds in Gale crater sedimentary rocks, with chemical structures of up to six carbons. Here, we report the detection of decane (C10H22), undecane (C11H24), and dodecane (C12H26) at the tens of pmol level, released from the Cumberland drilled mudstone sample, using a modified SAM analytical procedure optimized for the detection of larger organic molecules. Laboratory experiments support the hypothesis that the alkanes detected were originally preserved in the mudstone as long-chain carboxylic acids. The origin of these molecules remains uncertain, as they could be derived from either abiotic or biological sources.

¹Markus Patzek,^2,3Yogita Kadlag,⁴Miriam Rüfenacht,⁵Evelyn Füri,⁶Andreas Pack,¹Addi Bischoff,²Harry Becker,²Robbin Visser,²Timm John,⁴Maria Schönbächler
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14343]
¹Institut für Planetologie, University of Münster, Münster, Germany
²Freie Universität Berlin, Institut für Geologische Wissenschaften, Berlin, Germany
³Physical Research Laboratory, Ahmedabad, Gujarat, India
⁴Institute of Geochemistry and Petrology, ETH Zurich, Zurich, Switzerland
⁵Université de Lorraine, CNRS, CRPG, Nancy, France
⁶Universität Göttingen, Geowissenschaftliches Zentrum, Göttingen, Germany
Published by arrangement with John Wiley & Sons

A multi-element isotope (N, O, Ti, and Cr) study was conducted on C1 and CM-like clasts hosted in achondrites and chondrite breccias to understand the genesis of these chondritic clasts. The mineralogy, O, and N isotopes confirm that CM-like clasts in howardites and polymict eucrites closely resemble CM chondrite-like material. The O and Cr isotope composition of C1 clasts in CR chondrites overlaps with those of CR chondrites, implying either formation in a similar nebular environment or resemblance to local CR material that underwent more extensive in situ alteration. Notably, these clasts are less enriched in 15N than bulk CR chondrites. In contrast, C1 clasts in ureilites are enriched in 15N relative to the Earth’s atmosphere by ~100‰ setting them apart from any other known solar system material. They display elevated 17O and 18O values and lie along the CCAM line. In addition, a C1 clast from an ureilite represents the most 54Cr-enriched and 50Ti-depleted endmember among the carbonaceous chondrites. Altogether, these isotopic characteristics suggest that C1 clasts in ureilites represent material not sampled by any known meteorite group. Overall, this study highlights the presence of primitive, isotopically distinct materials in the early outer solar system, some of which were transported to the inner solar system to the accretion region of the host parent bodies.

^1,2,3Alice Macente,^3,4,5Luke Daly,³Sammy Griffin,^6,7,8Maria Gritsevich,^6,7Jarmo Moilanen,³Josh Franz Einsle,⁹Patrick Trimby,¹⁰Chris Mulcahy,¹⁰Jonathan Moffat,¹¹Alexander M. Ruzicka
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14344]
¹School of Civil Engineering, University of Leeds, Leeds, UK
²Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK
³School of Geographical and Earth Sciences, University of Glasgow, Glasgow, UK
⁴Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales, Australia
⁵Department of Materials, University of Oxford, Oxford, UK
⁶Faculty of Science, University of Helsinki, Helsinki, Finland
⁷Finnish Fireball Network, Helsinki, Finland
⁸Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russia
⁹Carl Zeiss Limited, Cambourne, UK
¹⁰Oxford Instruments Nanoanalysis, High Wycombe, UK
¹¹Department of Geology and Cascadia Meteorite Laboratory, Portland State University, Portland, Oregon, USA
Published by arrangement with John Wiley & Sons

Combining electron backscatter diffraction (EBSD) with X-ray computed tomography (XCT) offers a comprehensive approach to investigate shock deformation and rock texture in meteorites, yet such integration remains uncommon. In this study, we demonstrate the synergistic potential of XCT and EBSD in revealing deformation metrics, thereby enhancing our understanding of petrofabric strength and shock-induced deformation. Our analysis focuses on the Ozerki (L6, S4/5, W0) meteorite fall, which was instrumentally observed on June 21, 2018, and subsequently recovered by the Ural’s branch of the Russian Fireball Network (UrFU) recovery expedition a few days later. The trajectory analysis conducted by the Finnish Fireball Network facilitated the prompt retrieval of the meteorite. We show that Ozerki is deformed, with a moderate strength foliation fabric defined by metal and sulfide grain shapes. Microstructural analysis using EBSD shows that the parent body was likely still thermally active during this impact event. Our data suggest that these microstructures were likely produced during an impact while the Ozerki’s parent body was still warm.

^1,2Tianqi Zhang,^1,3Qi Tao,^1,2Xiaorong Qin,^2,4Yuchun Wu,^1,2Jiaxin Xi,^1,3Xiaoliang Liang,^1,3Hongping He,⁵Sridhar Komarneni
Journal of Geophyical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2024JE008619]
¹State Key Laboratory of Deep Earth Processes and Resources, & Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, PR China
²University of Chinese Academy of Sciences, Beijing, PR China
³CAS Center for Excellence in Deep Earth Science, Guangzhou, PR China
⁴State Key Laboratory of Solar Activity and Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, PR China
⁵Department of Ecosystem Science and Management and Materials Research Institute, 204 Energy and the Environment Laboratory, The Pennsylvania State University, University Park, PA, USA
Published by arrangement with John Wiley & Sons

Despite the anticipated abundant carbonates due to historical atmospheric CO2 levels, Mars presents a geological puzzle with MgFe-smectites dominating the Noachian and early Hesperian terrains, contrasted by sparse carbonate deposits. To address this point, we explored the impact of CO2 on MgFe-smectite formation, emphasizing the role of variable Si concentrations within the simulated Martian environment. Hydrothermal experiments, conducted under a constant CO2 concentration (C0.5) and varying Si concentrations (Si0.5 to Si4), reveal a transformation from pyroaurite to MgFe-smectite via lizardite as an intermediary phase. This transformation underscores the crucial role of Si in this mineral sequence. Notably, experiments demonstrate that the interlayer CO32− in pyroaurite is released into aqueous environments during the mineral conversion, potentially impacting the Martian CO2 budget. These findings could explain isolated carbonate outcrops and the possibility of hydrotalcite-group minerals on Mars today. Further Mars exploration should consider identifying hydrotalcite-group minerals for their implications on the planet’s climate and habitability.

^1,2Shuya Tan,^1,3,4Yasuhito Sekine,²Takazo Shibuya
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008591]
¹Earth-Life Science Institute (ELSI), Tokyo Institute of Technology, Tokyo, Japan
²Institute for Extra-cutting-edge Science and Technology Avantgarde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
³Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa, Japan
⁴Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Japan
Published by arrangement with John Wiley & Sons

Enceladus’ ocean could support methanogenic life in terms of the availability of chemical energy (H2 and CO2) and nutrients (N and P). However, excess energy and nutrients in the ocean raise the question of why they remain abundant if Enceladus is inhabited. Terrestrial methanogens require trace metals, such as Co, Ni, Cu, Zn, and Mo, for their enzyme activation; nevertheless, the availability of these trace metals is largely unknown in Enceladus’ ocean. Here, we investigate concentrations of dissolved trace metals in Enceladus based on hydrothermal experiments and thermodynamic equilibrium calculations in order to understand the minerals that control their concentrations in water-rock interactions. Our results show that Ni and Co concentrations in hydrothermal fluids can be controlled by dissolution of a sulfide mineral, pentlandite, in chondritic rocks. In a pH range for Enceladus’ ocean, our calculations show that hydrothermal environments would be the source of dissolved Ni and Co. Given a suggested range of water chemistry (pH and dissolved species) of Enceladus’ ocean, Ni, Zn, and Mo concentrations in hydrothermal fluids would be comparable to the levels required for terrestrial methanogens. However, both Co and Cu concentrations would be depleted compared with the levels required for terrestrial methanogens. We suggest that if methanogenic life in Enceladus requires trace metals at the same levels as for terrestrial methanogens, the availability of Co and Cu could control the activity of methanogenesis, possibly leaving excess chemical energy and nutrients in the ocean.

¹Sohei Wada,¹Ken-ichi Bajo,^1,2Tomoya Obase,¹Hisayoshi Yurimoto
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14346]
¹Department of Natural History Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
²Department of Earth and Planetary Sciences, Institute of Science Tokyo, Meguro, Tokyo, Japan
Published by arrangement with John Wiley & Sons

Solar wind (SW) is preserved in meteorites as abundant solar noble gases. We performed in situ 4He isotope imaging of mineral grains in the CR2 chondrite matrix of Northwest Africa 801 using time-of-flight secondary neutral mass spectrometry with strong-field post ionization. 4He+ signals were detected along the surfaces of individual grains of Fe-Ni metal, ferrihydrite, olivine, pyroxene, and troilite. The high 4He concentrations along the surfaces indicate implantation of SW into the mineral grains. We determined the SW-4He fluence of eight mineral grains from the line profiles across the grain boundaries. SW-4He fluence ranged from 2.7 × 1016 to 58 × 1016 atoms cm−2. These fluences were then used to calculate the SW irradiation durations. Assuming irradiation occurred at 4 astronomical units, the durations ranged from 3.8 to 82 kyr. These durations correspond to the residence time of individual mineral grains on the surface of the parent body. The variation in residence time for the mineral grains suggests variable durations for local mixing and burial processes on the parent body. The SW exposure ages provide insights into the gardening rate driven by small-scale impact mixing processes on the parent body.

^1,2Peter Jenniskens et al. (>10)
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14337]
¹SETI Institute, Mountain View, California, USA
²NASA Ames Research Center, Moffett Field, California, USA
Published by arrangement with John Wiley & Sons

The Aguas Zarcas (Costa Rica) CM2 carbonaceous chondrite fell during nighttime in April 2019. Security and dashboard camera videos of the meteor were analyzed to provide a trajectory, light curve, and orbit of the meteoroid. The trajectory was near vertical, 81° steep, arriving from an ~109° (WNW) direction with an apparent entry speed of 14.6 ± 0.6 km s−1. The meteoroid penetrated to ~25 km altitude (5 MPa dynamic pressure), where the surviving mass shattered, producing a flare that was detected by the Geostationary Lightning Mappers on GOES-16 and GOES-17. The cosmogenic radionuclides were analyzed in three recovered meteorites by either gamma-ray spectroscopy or accelerator mass spectrometry (AMS), while noble gas concentrations and isotopic compositions were measured in the same fragment that was analyzed by AMS. From this, the pre-atmospheric size of the meteoroid and its cosmic ray exposure age were determined. The studied samples came from a few cm up to 30 cm deep in an object with an original diameter of ~60 cm that was ejected from its parent body 2.0 ± 0.2 Ma ago. The ejected material had an argon retention age of 2.9 Ga. The object was delivered most likely by the 3:1 or 5:2 mean motion resonances and, without subsequent fragmentation, approached the Earth from a low i < 2.8° inclined orbit with a perihelion distance q = 0.98 AU close to the Earth’s orbit. The steep entry trajectory and high strength resulted in deep penetration in the atmosphere and a relatively large fraction of surviving mass.