^1,2V. P. Singh,^1,2N. G. Rudraswami,^3,4Nittala V. Chalapathi Rao,⁵Matthew J. Genge,¹M. Pandey,^1,2S. Sreekuttan,³S. Chattopadhaya
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14256]
¹National Institute of Oceanography (Council of Scientific and Industrial Research), Dona Paula, Goa, India
²Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
³Department of Geology, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
⁴National Centre for Earth Science Studies, Ministry of Earth Sciences, Thiruvananthapuram, India
⁵Department of Earth Science and Engineering, Imperial College London, London, UK
Published by arrangement with John Wiley & Sons

The Cretaceous–Paleogene (K-Pg) boundary represents the extinction of ~70% of species, a prominent Chicxulub impact event and Deccan volcanism. This work reports the first attempt to extract the micrometeorites (MMs) from the Deccan intertrappean horizons. Eighty-one spherical particles were studied for their morphological, textural, and chemical characteristics. Intact cosmic spherules with ferromagnesian silicates (6) and Fe-Ni oxide (7) compositions correspond to MMs from the deep sea and Antarctica. Silicate and Fe-Ni spherules in this study showcase remarkable preservation, a testament to the highly favorable conditions present. Fe spherules (38) with iron oxide compositions exhibit diagenetic alteration during preservation. Textural analysis of 30 Fe spherules reveals a dendritic, interlocking pattern and slightly elevated Mn content, suggesting these may be fossilized I-type MMs. However, eight Fe spherules with blocky and cubical granular textures resemble oxidized pyrite spherules. Al-Fe-Si spherules (30) possess a significant enrichment of Al and Si within their Fe-oxide-dominated composition. Group-I Al-Fe-Si spherules (15) display zoned Al-Fe-Si oxide composition, dendritic Mg-Cr spinel grains, and aerodynamic features, all indicative of impact spherules. The finding of these impact spherules from sampled Deccan intertrappean layer raises the possibility that these paleosols were deposited during the Chicxulub impact event, the only identified impact event with global distribution during the Deccan volcanism time frame. This unique location provides an opportunity for the simultaneous collection of well-preserved MMs, impact, and volcanic spherules. The exceptional preservation of the studied MMs is likely due to a combination of non-marine environments, atypical climatic conditions, and rapid deposition. This study further investigates the potential role of cosmic dust flux in the K-Pg extinction event. We propose that the enhanced cosmic dust flux, a likely scenario during the K-Pg boundary period, synergistically mixing with impact dust in the upper atmosphere, may have intensified and extended the harsh climatic conditions at the K-Pg boundary. Subsequently, the deposition of this dust, enriched in bioavailable iron, on Earth’s surface might have contributed to the swift recovery of life and environmental conditions.

^1,2Y. Srivastava,¹A. Basu Sarbadhikari,³A. Yamaguchi,⁴A. Takenouchi,⁵J. M. D. Day,⁶T. Ubide
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14257]
¹Physical Research Laboratory, Ahmedabad, India
²Indian Institute of Technology, Gandhinagar, Gujarat, India
³National Institute of Polar Research (NIPR), Tokyo, Japan
⁴The Kyoto University Museum, Kyoto University, Kyoto, Japan
⁵Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
⁶School of the Environment, The University of Queensland, Brisbane, Queensland, Australia
Published by arrangement with John Wiley & Sons

Lunar basaltic meteorite Asuka-881757 (A-881757), a member of the source crater paired YAMM meteorites (Yamato-793169, A-881757, Miller Range 05035 and Meteorite Hills 01210), provides information on potassium-rare earth element-phosphorous (KREEP)-free magmatic sources within the Moon. Asuka-881757 is an unbrecciated and Fe-rich (Mg# 36) gabbro with coarse pyroxene (2–8 mm) and plagioclase (1–3 mm). The coarse pyroxene preserves mm-scale, near-complete hour-glass sector zoning with strong Ca and Fe partitioning, similar to some Fe-rich Apollo basalts. In contrast to the most Mg-rich Apollo basalts, A-881757 contains various types of symplectites (~8 vol%) formed by the breakdown of pyroxferroite due to slow cooling, resembling a few extreme Fe-rich (Mg#
40) Apollo basalts. Petrographic observations and thermodynamic modeling suggest crystallizing in the order: Fe-poor pyroxenes (Mg# 58–55) → co-crystallized plagioclase and Fe-rich pyroxenes (Mg# 49–20) → late-stage assemblage including Fe-augite, Fayalite, and Fe-Ti oxides. Combining phase stability at variable P–T with petrographic observations, the minimum depth of formation of the A-881757 parent magma can be constrained to between 60 and 100 km. KREEP-free basalts (such as A-881757 and the YAMM meteorites) originated from a relatively shallow mantle source and later underwent polybaric crystallization that occurred prior to eruption at the lunar surface. In contrast, the Apollo mare basalts mostly crystallized within lava flows from relatively deeper-seated mantle sources. The crystallization of A-881757 and other YAMM meteorites is unlike most Apollo basalts from the Procellarum KREEP terrane, and likely represent hidden cryptomare basalts close to lunar surface.

¹Mengyan Zheng,^1,2Yoko Kebukawa,¹Yuka Hayashi,¹Kensei Kobayashi
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14259]
¹Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, 240-8501 Yokohama, Japan
²Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, 152-8551 Tokyo, Japan
Published by arrangement with John Wiley & Sons

CI, CM, and CR carbonaceous chondrites contain hydrous minerals, indicating that their parent bodies underwent aqueous alteration at low temperatures. Some of these chondrites, such as heated CM, CI, and CY chondrites, experienced thermal dehydration by impacts or solar radiation after aqueous alteration. This study conducted heating experiments on carbonaceous chondrites and evaluated their dehydration/dehydroxylation kinetics in an effort to explain the thermal history of the parent asteroids of heated carbonaceous chondrites using their degrees of dehydration/dehydroxylation of hydrous minerals. Murchison (CM2.5) and Ivuna (CI1), relatively primitive (having not undergone thermal alteration) carbonaceous chondrites, were used as starting materials. Weakening in the OH band at ~3680 cm−1 (2.72 μm) with isothermal heating at 350–500°C (Murchison) and 450–525°C (Ivuna) were observed under in situ infrared spectroscopy (FT-IR) equipped with a heating stage. To determine the rate constants, the decrease in the OH band was fitted using kinetic models such as first-order reactions, two-dimensional diffusion, and three-dimensional diffusion. The apparent activation energies and frequency factors were determined using the Arrhenius equation. Time–temperature transformation diagrams were drawn to represent the decrease in the OH-band intensity as a function of temperature and heating duration. Such kinetic approaches can provide constraints on the temperature and time of the dehydration/dehydroxylation processes and enable us to estimate long-term effects from experiments in the laboratory within a short time.

¹Christopher J.-K. Yen et al. (>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14260]
¹Department of Earth and Planetary Sciences and the McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis, Missouri, USA
Published by arrangement with John Wiley & Sons

Northwest Africa (NWA) 12384 is a lunar polymict breccia composed almost entirely of basaltic components. The clast content includes low- to very-low-Ti volcanic picritic glass, basaltic vitrophyre, and crystalline pigeonite basalt—an assemblage of volcanic materials that can be tested for petrogenetic relationships. We present the inferred history of select mare components of NWA 12384 as suggested by texture, mineralogy, and petrography, and compare them to Apollo samples and other lunar meteorites. In addition, we used the volcanic glasses in the breccia as a primary composition for crystallization modeling and comparison to the lithic clast compositions. We find that the mafic clasts in NWA 12384 cannot be derived from the picritic glass through a common liquid line of descent because of higher Ti content, though they may have crystallized from a separate, common liquid line of descent. These clasts could represent local source-region heterogeneity or differential assimilation of more Ti-rich material. Pb-Pb SIMS analyses of a large basalt clast in NWA 12384 reveal an age of 3044 ± 41 Ma (2σ), which is used together with the chemical data and 4π cosmic ray exposure age of less than 20 kyr and terrestrial age of between 3.1 and 17.3 kyr to constrain the possible locations of provenance for this meteorite.

¹van Kooten, Elishevah,²Zhao, Xuchao,²Franchi, Ian,³Tung, Po-Yen,³Fairclough, Simon,³Walmsley, John,¹Onyett, Isaac,¹Schiller, Martin,^1,4Bizzarro, Martin
Science Advances 10, eadp1613 Open Access Link to Article [DOI 10.1126/sciadv.adp1613]
¹Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen, 1350, Denmark
²School of Physical Sciences, Open University, Milton Keynes, MK7 6AA, United Kingdom
³Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, United Kingdom
⁴Institut de Physique du Globe de Paris, Université Paris Cité, 1 Rue Jussieu, Paris, 75005, France

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¹Hausrath E.M. et al. (>10)
Minerals 14, 591 Open Access Link to Article [DOI 10.3390/min14060591]
¹Department of Geoscience, University of Nevada, Las Vegas, 89154, NV, United States

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¹Prasad B.,¹Das H.S.
Monthly Notices of the Royal Astronomical Society 532, 22-31 Open Access Link to Article [DOI 10.1093/mnras/stae1409]
¹Department of Physics, Assam University, Silchar, 788011, India

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¹H.Kalucha et al. (>10)
Journal of Geophysical Research (Planets) Link to Article [https://doi.org/10.1029/2023JE008138]
¹California Institute of Technology, Pasadena, CA, USA
Published by arrangement with John Wiley & Sons

The Mars 2020 Perseverance Rover imaged diagenetic textural features in four separate sedimentary units in its exploration of the 25-m-thick Shenandoah formation at Jezero Crater, Mars, that we interpreted as probable concretions. These concretions were most abundant in the Hogwallow Flats member of the Shenandoah formation and were restricted to the light-toned, platy, sulfur-cemented bedrock at outcrop surfaces, whereas the finely laminated, darker toned, mottled and deformed strata lack concretions. The concretions also had a wide range of morphologies including concentric, oblate, urn, and spheroidal shaped forms that were not clustered, and ranged in size from ∼1 to 16 mm with a median of 2.65 mm. The elemental composition of the concretions compared to the bedrock had greater abundance of magnesium and calcium salts, silicates, and possibly hematite. We compared these Jezero Crater concretions to the geochemistry of concretions from previously published studies and from two new terrestrial analog sites (Gallup Formation, New Mexico and Torrey Pines, California). In addition, we measured organic carbon content of three terrestrial sedimentary analogs of increasing age that contain concretions (Torrey Pines (Pleistocene), Gallup Formation (∼89 Ma), and Moodies Group (∼3.2 Ga)). All measured concretions contained significant concentrations of organic carbon with the maximum organic carbon content (∼2 wt. % Total organic carbon) found in the Moodies Group concretions. Organic carbon abundances in terrestrial concretions was controlled more by the formation mechanism and relative timing of concretion development rather than deposit age. These findings suggested that concretions at Jezero Crater reflect local sites of enhanced biosignature preservation potential.

¹Patrick M. Shober,^2,3Marc W. Caffee,⁴Phil A. Bland
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14246]
¹Institut Mécanique Céleste et de Calcul des Éphemerides, Observatoire de Paris, PSL, Paris, France
²Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana, USA
³Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, Indiana, USA
⁴Space Science & Technology Centre, School of Earth and Planetary Sciences, Curtin University, Bentley, Western Australia, Australia
Published by arrangement with John Wiley & Sons

This study investigates the expected cosmic-ray exposure (CRE) of meteorites if they were to be ejected by a near-Earth object, that is, from an object already transferred to an Earth-crossing orbit by an orbital resonance. Specifically, we examine the CRE ages of CI and CM carbonaceous chondrites (CCs), which have some of the shortest measured CRE ages of any meteorite type. A steady-state near-Earth carbonaceous meteoroid probability density function is estimated based on the low-albedo near-Earth asteroid population, including parameters such as the near-Earth dynamic lifetime, the impact probability with the Earth, and the orbital parameters. This model was then compared to the orbits and CRE ages of the five CC falls with precisely measured orbits: Tagish Lake, Maribo, Sutter’s Mill, Flensburg, and Winchcombe. The study examined two meteoroid ejection scenarios for CI/CM meteoroids: Main Belt collisions and ejections in near-Earth space. The results indicated that applying a maximum physical lifetime in near-Earth space of 2–10 Myr to meteoroids and eliminating events evolving onto orbits entirely detached from the Main Belt (Q < 1.78 au) significantly improved the agreement with the observed orbits of carbonaceous falls. Additionally, the CRE ages of three of the five carbonaceous falls have measured CRE ages one to three orders of magnitude shorter than expected for an object originating from the Main Belt with the corresponding semi-major axis value. This discrepancy between the expected CRE ages from the model and the measured ages of three of the carbonaceous falls indicates that some CI/CM meteoroids are being ejected in near-Earth space. This study proposes a nuanced hypothesis involving meteoroid impacts and tidal disruptions as significant contributors to the ejection and subsequent CRE age accumulation of CI/CM chondrites in near-Earth space.

¹Maximilian P. Reitze,^1,2Christian Renggli,¹Andreas Morlok,¹Iris Weber,³Uta Rodehorst,¹Jasper Berndt,¹Stephan Klemme,¹Harald Hiesinger
Journal of Geophysical Research (Planets) (in Press) Open Access Link to Article [https://doi.org/10.1029/2024JE008483]
¹Universität Münster, Institut für Planetologie, Münster, Germany
²Max Planck Institute for Solar System Research, Göttingen, Germany
³MEET – Münster Electrochemical Energy Technology, Münster, Germany
Published by arrangement with John Wiley & Sons

We synthesized the solid solution between the sulfides CaS (oldhamite) and MgS (niningerite). Electron microprobe and X-ray diffraction showed homogeneous and pure samples after the synthesis. The calculated lattice parameters fit to earlier literature data. Mid-infrared spectroscopy of the samples reveal that the produced sulfides were fragile and tend to alternate very fast. However, we were able to provide clean reflectance spectra of all samples. The spectra of un-altered samples show no peaks or bands but a rather constant spectrum within the analyzed spectral range between 7.0 and 12.5 μm. The altered spectra contain signatures of sulfates and carbonates and probably further compounds. The gathered data help to understand the formation conditions of the studies sulfides as it shows that the solvus exists in the CaS-MgS system between 1000°C and 1200°C. In addition, the infrared data will help to improve remote sensing in the mid-infrared of planetary objects that might be covered with sulfide containing material like asteroids or Mercury.