¹Fabian Zahnow,¹Tido Stracke,¹Tommaso di Rocco,²Thilo Hasse,¹Andreas Pack
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14084]
¹Geowissenschaftliches Zentrum, Universität Göttingen, Göttingen, Germany
²Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
Published by arrangement with John Wiley & Sons

In this study, we present a method for high precision Δ′17O (Δ′17ORL = ln(δ17O + 1) – λRL ln(δ18O + 1)) analysis of small mass silicate and oxide materials. The analyses were conducted by laser fluorination in combination with gas chromatography and continuous flow isotope ratio monitoring gas spectrometry. We could analyze the oxygen isotope composition of samples down to 1 μg, which corresponded to about 13 nmol O2. The analytical error (we report the 1σ external reproducibility of a single analysis) in δ18O increases with decreasing sample sizes from ~0.2‰ for ~20 μg samples to ~0.9‰ for 1 μg samples. For Δ′17O, we achieved an external reproducibility of 0.04‰ for a sample mass range between 1 and 27 μg. The uncertainty in Δ′17O is smaller than the uncertainty in δ18O due to the correlated errors in δ17O and δ18O. We applied the method to urban micrometeorites, that is, small meteorites (<2 mm) that were sampled from a rooftop in Berlin, Germany. A total of 10 melted micrometeorites (S-type cosmic spherules, masses between 11 and 22 μg) were analyzed. The oxygen isotope compositions are comparable to that of modern Antarctic collections, indicating that the urban micrometeorites sample the same population. No indication for terrestrial weathering had been identified in the studied set of urban micrometeorites making them suitable materials for the study of micrometeorite origins.

¹S. Loehle,²J. Vaubaillon,³P. Matlovič,³J. Tóth
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115817]
¹High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29, 70569 Stuttgart, Germany
²IMCCE, Observatoire de Paris, PSL, 77 Av. Denfert Rochereau, Paris, 75014, France
³Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
Copyright Elsevier

The paper reports the determination of luminous efficiency values from ground testing of a comprehensive set of meteorite samples. The ground testing data is translated with commonly used ground to flight extrapolation analogies from atmospheric entry maneuver’s engineering into values of a night observation. This results in a meteor at an altitude of 80 km with a flight speed of 11.7 km/s of a 34.8 mm diameter spherical meteoroid. A method is developed to determine the total luminous efficiency
in the bands U, B, V, R, and I from the radiance data and the measured mass loss. For the first time, a measurement of luminous efficiency became possible for known materials. The values itself are in the range of 0.01% to
1%, which is in the range of previous studies from meteor measurements.

¹A. Nakamura,¹M. Miyahara,^2,3H. Suga,⁴A. Yamaguchi,⁵D. Wakabayashi,⁵S. Yamashita,^5,6Y. Takeichi,¹K. Kukihara,²Y. Takahashi,⁷E. Ohtani
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2023JE007951]

¹Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, Japan
²Department of Earth and Planetary, Graduate School of Science, The University of Tokyo, Tokyo, Japan
³Japan Synchrotron Radiation Research Institute, Hyogo, Japan
⁴National Institute of Polar Research, Tokyo, Japan
⁵Institute of Materials Structure Science, High-Energy Accelerator Research Organization (KEK), Tsukuba, Japan
⁶School of Engineering, Osaka University, Osaka, Japan
⁷Department of Earth Sciences, Graduate School of Science, Tohoku University, Sendai, Japan
Published by arrangement with John Wiley & Sons

Alteration minerals in one of the Martian meteorite nakhlites, Yamato (Y) 000802, were studied to understand the alteration process and conditions. Mn-precipitates are discovered between altered plagioclase grains in Y 000802. Mn-precipitates consist of hausmannite (), manganite (γ-Mn³⁺OOH), rhodochrosite (Mn²⁺CO₃), and a trace amount of Mn⁴⁺O₂ mineral. Jarosite ) is also found. Mn²⁺ dissolved from olivine contributes to the formation of Mn-precipitates. A weakly acidic-neutral fluid containing a trace amount of  altered the olivine, and Mn²⁺ was dissolved into the fluid. The fluid also reacted with plagioclase and probably induced dealkalization of plagioclase, causing a local strong alkaline environment. Plagioclase was altered to ferroan saponite-nontronite + amorphous SiO₂ under alkaline conditions. Simultaneously, Mn^2+/3+-precipitates were formed from the Mn²⁺-containing fluid in the interstices between the altered plagioclase grains under the strong alkaline reducing environment. These alterations occurred in the deep part of the nakhlite body, where they are isolated from Martian subsurface water, including strong oxidants. The formation of Mn^2+/3+-precipitates may have been triggered by the melting of permafrost caused by an impact event around ∼633 Ma. Later, the nakhlite body was probably excavated by another impact, making it susceptible to water including strong oxidants. Pyrrhotite was dissolved and a highly acidic oxidizing fluid was formed, which would induce the formation of jarosite and the Mn⁴⁺O₂ mineral between ∼633 Ma and ∼11 Ma.

¹R. Ravichandran,¹S. Loehle,¹F. Hufgard,¹D. Leiser,⁴F. Zander,⁵L. Ferrière,²J. Vaubaillon,³P. Matlovič,³J. Tóth
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115818]
¹High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29, 70569 Stuttgart, Germany
²IMCCE, Observatoire de Paris, PSL, 77 Av. Denfert Rochereau, Paris, 75014, France
³Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
⁴Institute of Advanced Engineering and Space Sciences, University of Southern Queensland, Toowoomba 4350, Queensland, Australia
⁵Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria
Copyright Elsevier

Optical emission spectra between 522-580 nm of ablating meteorites have been recorded at frame rates as high as 1 kHz for the first time during ground testing with simultaneous spatial and temporal resolution. A novel high frame rate emission spectroscopy arrangement has been developed and employed to diagnose the ablating meteorites in several experimental campaigns. In addition to the identification of species from emission lines detected, the resulting high-speed spectral data were used to study the temporal and spatial evolution of melting droplets and the associated spectral signatures. The time history of radiance from the atomic species emission was used to interpret the fragmentation behavior of various meteorites. Chelyabinsk meteorite exhibit almost constant radiance over time indicating steady droplet detachment whereas Ragland meteorite shows infrequent radiance peaks corresponding to random fragmentation/droplet detachment of varying sizes. A gradual rise in radiance history from iron meteorite Mount Joy shows that it takes finite time for melting and accumulation of droplets.

¹Vasilij G. Chiorny,^1,2Vasilij G. Shevchenko,^1,2Ivan G. Slyusarev,^1,2Olga I. Mikhalchenko,^1,3Yurij N. Krugly,³Dagmara Oszkiewicz
Planetary and Space Science (in Press) Open Access Link to Article [https://doi.org/10.1016/j.pss.2023.105779]
¹Institute of Astronomy of V.N. Karazin Kharkiv National University, Kharkiv 61022, Sumska Str. 35, Ukraine
²Department of Astronomy and Space Informatics of V.N. Karazin Kharkiv National University, Kharkiv 61022, 4 Svobody Sq., Ukraine
³Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286 Poznan, Poland
Copyright Elsevier

We currently do not have a copyright agreement with this publisher and cannot display the abstract here

^1,2V. Santiago Quinteros,³Thomas Dylan Mikesell,⁴Griffiths Luke,¹X. Jerves Alex
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115812]
¹Advanced Modelling, Norwegian Geotechnical Institute, Oslo, Norway
²Department of Civil Engineering and Energy Technology, Oslo Metropolitan University, Norway
³Remote Sensing and Geophysics, Norwegian Geotechnical Institute, Oslo, Norway
⁴Integrated Geotechnology, Norwegian Geotechnical Institute, Oslo, Norway
Copyright Elsevier

A comprehensive program of geotechnical index tests performed on two regolith simulants, namely LHS-1 and LMS-1, are presented and discussed in this study. The index tests included a 2D analysis of particles shapes and measurements of grain density, particle size distribution, plastic and liquid limit, thermal conductivity, and maximum and minimum dry density. The detailed testing methodologies are provided, and their results are discussed and compared with data available in the literature from similar tests on the same regolith simulants. Additionally, a thorough analysis of the data in contrast with data of lunar soils is presented. The observed spread on the index tests results is explained by the indiscriminate use of different procedures, regolith mass, and methodologies across different laboratories and highlight the importance and urgency for planetary scientist to agree on best practices in geotechnical testing of regolith and extra-terrestrial simulants.

¹Kierra Wilk,²Janice L. Bishop,³Catherine M. Weitz,⁴Mario Parente,⁴Arun M. Saranathan,^4,5Yuki Itoh,⁶Christoph Gross,⁷Jessica Flahaut,⁵Frank Seelos
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115800]
¹Brown University (Providence, RI)
²SETI Institute & NASA-Ames (Mountain View, CA)
³Planetary Science Institute (Tucson, AZ)
⁴University of Massachusetts at Amherst (Amherst, MA)
⁵Johns Hopkins University Applied Physics Lab (Laurel, MD)
⁶Free University of Berlin (Berlin, Germany)
⁷CRPG, CNRS/Université de Lorraine (Vandœuvre-lès-Nancy, France)
Copyright Elsevier

Intriguing outcrops in Ius Chasma provide a window into past aqueous processes in Valles Marineris, Mars. Hydrous sulfate minerals are abundant throughout this region, but one area in Ius Chasma includes phyllosilicates, opal, and additional materials with unusual spectral features. This study at Geryon Montes, an east-west horst that divides Ius Chasma into a northern and southern canyon, exploits recent advances in image calibration and feature extraction techniques for analysis of hyperspectral images acquired by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Specifically, a unique spectral “doublet” feature with absorptions at 2.21–2.23 and 2.26–2.28 μm is isolated at the border of phyllosilicate-bearing and sulfate-bearing regions in Ius Chasma and surveyed to characterize outcrops that may represent a changing climate on Mars. We document and map three distinct forms of this “doublet” material in relation to phyllosilicates and opal. Analyses of compositional maps derived from CRISM overlain on High Resolution Stereo Camera (HRSC) and High Resolution Imaging Science Experiment (HiRISE) imagery has revealed the presence of these hydrated outcrops along the wall rocks below a breach in the Geryon Montes, bordering a canyon containing abundant hydrated sulfates. Our investigation supports formation of these unique alteration phases through acid alteration of ancient smectites in the wall rock as the sulfate brine overflowed the south canyon of Ius Chasma at the breach in Geryon Montes and penetrated the deeper northern canyon.

¹Shaofan Che,¹Kenneth J. Domanik,¹Yao-Jen Chang,^1,2Thomas J. Zega
Earth and Planetary Science Letters 621, 118374 Link to Article [https://doi.org/10.1016/j.epsl.2023.118374]
¹Lunar and Planetary Laboratory, University of Arizona, Tucson AZ, United States of America
²Department of Materials Science and Engineering, University of Arizona, Tucson AZ, United States of America
Copyright Elsevier

The important role that aqueous fluids played during the evolution of carbonaceous chondrites (CCs) and the carbonaceous asteroids that they derive from is well documented. In comparison, our understanding of how such fluids affected ordinary chondrites (OCs) and their S-type asteroid parent bodies is less mature in part due to the intense thermal metamorphism that overprinted the records of alteration. Further, that only a small suite of unequilibrated OCs shows evidence of hydration hinders our understanding of the role that fluids played in the evolution of OCs and S-type asteroids. Here we report a microstructural analysis on halite (NaCl) and sphalerite (ZnS) in Sidi El Habib 001 (SEH 001), a H5 OC that provides new insights into the role of fluids on the OC parent bodies. Our data reveal that halite contains alteration relicts of submicron silicates, and that widespread sphalerite spatially correlates with halite. This relationship suggests that sphalerite formed from the same hydrothermal fluid that precipitated halite, consistent with experimental and theoretical work showing that Cl-rich fluids induce complexation of Zn and significantly enhance its mobility. We hypothesize that Cl-rich hydrothermal fluids resulted from melting of locally concentrated HCl hydrate, which produced acidic fluids capable of dissolving chondritic mineral phases. The pH of the fluid presumably varied on a micrometer scale due to different rates of hydrolysis reactions as a function of grain size, as illustrated by the absence of halite in SEH 001 chondrules. Such a fluid-alteration model is attractive because it offers a reasonable explanation for the limited and heterogeneous alteration effects in OCs.

^1,2,3Benjamin E. Cohen,^1,4Darren F. Mark,⁵William S. Cassata,³Lara M. Kalnins,²Martin R. Lee,^2,6Caroline L. Smith,^7,8David L. Shuster
Earth and Planetary Science Letters 621, 118373 Open Access Link to Article [https://doi.org/10.1016/j.epsl.2023.118373]
¹Scottish Universities Environmental Research Centre (SUERC), East Kilbride, UK
²School of Geographical and Earth Sciences, University of Glasgow, UK
³School of GeoSciences, University of Edinburgh, UK
⁴Department of Earth and Environmental Sciences, University of St Andrews, UK
⁵Lawrence Livermore National Laboratory, CA, USA
⁶Department of Earth Sciences, The Natural History Museum, London, UK
⁷Department of Earth and Planetary Science, University of California, Berkeley, CA, USA
⁸Berkeley Geochronology Center, Berkeley, CA, USA
Copyright Elsevier

The shergottites are the most abundant and diverse group of Martian meteorites and provide unique insights into the mafic volcanic and igneous history of Mars. Their ages, however, remain a source of debate. Different radioisotopic chronometers, including 40Ar/39Ar, have yielded discordant ages, leading to conflicting interpretations on whether the shergottites originate from young (mostly <700 Ma) or ancient (>4,000 Ma) Martian volcanoes. To address this issue, we have undertaken an 40Ar/39Ar investigation of seven shergottite meteorites utilizing an innovative approach to correcting data for cosmogenic isotope production and resolution of initial trapped components which, crucially, do not require assumptions concerning the sample’s geologic context. Our data yield statistically robust 40Ar/39Ar isochron ages ranging from 161 ± 9 Ma to 540 ± 63 Ma (2σ), synchronous with the U-Pb, Rb-Sr, and Sm-Nd ages for the respective meteorites. These data indicate that, despite experiencing shock metamorphism, the shergottites were sourced from the youngest volcanoes on Mars.

^1,2L. Folco,³P. Rochette,^1,2M. D’Orazio,^1,2M. Masotta
Geochimica et Cosmochimica Acta (in Press) Open Aceess Link to Article
[https://doi.org/10.1016/j.gca.2023.09.018]
¹Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria 53, Pisa, Italy
²CISUP, Centro per la Integrazione della Strumentazione dell’Università di Pisa, Lungarno Pacinotti, Pisa, Italy
³Aix-Marseille Université, CNRS, IRD, INRAE, UM 34 CEREGE, Aix-en-Provence, France
Copyright Elsevier

In the Earth’s crust, Ni is generally concentrated in mafic and ultramafic rocks and is coupled with Mg in Mg-olivine, Mg-pyroxene and spinel. Whether the Ni-rich, and in general, the mafic component of Australasian tektites and microtektites is terrestrial or meteoritic is still debated. To test the origin of the Ni-rich component, we studied the Ni versus Mg distribution in a large geochemical database of Australasian tektites (n = 208) and microtektites (n = 238) from the literature. Nickel contents of up to 428 µg/g in tektites and 678 µg/g in microtektites covary with Mg in tektites and in most (∼85%) of the microtektites defining a mixing trend between crustal and chondritic values, thereby documenting the chondritic origin of the Ni-rich component in Australasian tektites/microtektites. Mixing calculations indicate up to 4% and up to 6% by weight chondritic component in tektites and microtektites, respectively. A possible mafic component of terrestrial origin is observed in a minority of tektite and microtektite specimens. This finding is consistent with previous works suggesting a possible occurrence of a chondritic signature in high-Ni tektites, based on the study of highly siderophile elements and Os isotopes, and high-Ni microtektites, based on Ni, Co, and Cr ratios. The combined geochemical and isotopic analysis of high-Ni tektites and microtektites in collections worldwide may thus reveal the chondritic impactor type that generated one of the presumably largest impacts in the Cenozoic.