¹Timo Hopp,¹Nicolas Dauphas,²Fridolin Spitzer,²Christoph Burkhardt,²Thorsten Kleine
Earth and Planetary Science Letters 577, 117245 Link to Article [https://doi.org/10.1016/j.epsl.2021.117245]
¹Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5743 South Ellis Avenue, Chicago, IL 60637, USA
²Institut für Planetologie, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
Copyright Elsevier

Nucleosynthetic Fe isotopic anomalies in meteorites may be used to learn about the early evolution of the solar system and to identify the origin and nature of the material that built the terrestrial planets. Using high-precision iron isotopic data of 23 iron meteorites from nine major chemical groups we show that all iron meteorites define the same dichotomy between non-carbonaceous (NC) and a carbonaceous (CC) meteorites previously observed for other elements. The Fe isotopic anomalies are predominantly produced by variations in 54Fe, where all CC iron meteorites are characterized by an excess in 54Fe relative to NC iron meteorites. This excess in 54Fe is accompanied by an excess in 58Ni observed in the same CC meteorite groups. Together, these overabundances of 54Fe and 58Ni are explained by nuclear statistical equilibrium either in type Ia supernovae or in the Si/S shell of core-collapse supernovae.

The Fe isotopic composition of Earth’s mantle plots on or close to correlations defined by Fe, Mo, and Ru isotopic anomalies in iron meteorites, indicating that throughout Earth’s accretion, the isotopic composition of its building blocks did not drastically change. While Earth’s mantle has a similar Fe isotopic composition to CI chondrites, the latter are clearly distinct from Earth’s mantle for other elements (e.g., Cr and Ni) whose delivery to Earth coincided with Fe. The fact that CI chondrites exhibit large Cr and Ni isotopic anomalies relative to Earth’s mantle, therefore, demonstrates that CI chondrites are unlikely to have contributed significant Fe to Earth and are not its main building blocks.

¹Sara S. Russell,¹M. D. Suttle,¹A. J. King
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13753]
¹Planetary Materials Group, Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD UK
Published by arrangement with John Wiley & Sons

We review the mineralogy, petrology, and abundance of petrological type 1 extraterrestrial material. Such material has been completely altered by aqueous processing on its parent bodies. As well as the four meteorite groups that contain type 1 members (CI, CM, CR, and CY), we summarize data from the 2019 fall Flensburg and a recent reanalysis of the “meteorite” Bench Crater found on the Moon, along with fine-grained micrometeorites, interplanetary dust particles, and xenoliths in meteorites. Type 1 materials exhibit a remarkably high diversity of alteration conditions (temperature, water-to-rock [W/R] ratios, and fluid composition) and starting mineralogy. Type 1 material comprises a significant component of the modern extraterrestrial flux to the Earth and was likely common throughout the solar system during the whole course of its history, pointing to both widespread accretion with ices and heating of parent bodies. Type 1 materials are composed predominantly of various phyllosilicates, carbonates, sulfides, and magnetite. Some type 1 materials appear to be part of a “CM clan” typified by serpentine-rich phyllosilicate compositions and an oxygen isotope composition that falls in the 16O-rich part of the CM field. Others span a wide range in δ18O (>30‰) and fall on or above the terrestrial fractionation line (+ve Δ17O). Positive Δ17O values are unusual for carbonaceous meteorites but are relatively common in type 1 materials. The wide variation in oxygen isotopes, as well as in textures, mineralogy, and bulk chemistry, points to multiple parent bodies that may originate in the inner and/or outer solar system. Cometary materials, or transition objects such as Main Belt comets or type D asteroids, are likely the source of much of the type 1 materials on Earth but relating them to specific parents requires more study.

^1,2Yogita Kadlag,²Jason Hirtz,¹Harry Becker,²Ingo Leya,³Klaus Mezger
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13756]
¹Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100, Berlin, 12249 Germany
²Physikalisches Institut, Universität Bern, Sidlerstrasse 5, Bern, 3012 Switzerland
³Institut für Geologie, Universität Bern, Baltzerstrasse 1+3, Bern, 3012 Switzerland
Published by arrangement with John Wiley & Sons

Different solar system objects display variable abundances of neutron-rich isotopes such as 54Cr, 50Ti, and 48Ca, which are commonly attributed to a heterogeneous distribution of presolar grains in different domains of the solar system. Here, we show that the heterogeneity of 54Cr/52Cr and the correlation of 54Cr/52Cr with Fe/Cr in metal fractions of EH3 chondrites and in inner solar system bodies can be attributed to variable irradiation of dust grains by solar energetic particles and variable mixing of irradiated material in the different domains of the inner solar nebula. The isotope variations in inner solar system objects can be generated by ∼300 y long local irradiation of mm- to cm-sized solids with average solar energetic particle fluxes of ∼105 times the modern value. The relative homogeneity of 53Cr/52Cr in inner solar system objects can be a consequence of the production of 53Mn by the early irradiation of dust, evaporation, and nebula-wide homogenization of Mn due to high temperatures, followed by Mn/Cr fractionation within the first few million years of the solar system. The 54Cr/52Cr of the Earth can be produced by irradiated pebbles and <15 wt% of CI chondrite like material. Alternatively, Earth may contain only a few % of CI chondrite like material but then must have an Fe/Cr ratio 10–15% higher than CI chondrites.

¹Åke V. Rosén,^1,2Beda A. Hofmann,³Frank Preusser,⁴Edwin Gnos,¹Urs Eggenberger,⁵Marc Schumann,⁶Sönke Szidat
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13758]
¹Institute of Geological Sciences, University of Bern, Baltzerstrasse 1+3, Bern, 3012 Switzerland
²Natural History Museum Bern, Bernastrasse 15, Bern, 3005 Switzerland
³Institute of Earth and Environmental Sciences, University of Freiburg, Alberstrasse 23b, Freiburg, 79104 Germany
⁴Natural History Museum of Geneva, 1, Route de Malagnou, Geneva, 1208 Switzerland
⁵Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, Freiburg, 79104 Germany
⁶Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern, 3012 Switzerland
Published by arrangement with John Wiley & Sons

We combine the search for young meteorites in the Omani-Swiss collection (˜1140 fall events collected 2001–2018) using 22Na and 44Ti with luminescence and 14C sediment ages from the Ramlat Fasad (RaF) dense collection area (DCA) of Oman to obtain combined terrestrial ages and maximum accumulation times, and test whether the proportion of young meteorites is consistent with the models of meteorite flux and weathering. Gamma-ray spectrometry data for 22Na show that two (0.17%) of the meteorites in the collection fell during the 20 yr preceding this study, consistent with the rates of meteorite accumulation. In the RaF DCA, meteorites are found on Quaternary to Neogene sediments, providing constraints for their maximum terrestrial ages. 44Ti activities of the RaF 032 L6 strewn field found on deflated parts of active dunes indicate an age of 0.2–0.3 ka while dune sand optically stimulated luminescence ages constrain an upper age of 1.6 ka. Extensive sediment dating using luminescence methods in the RaF DCA area showed that all other meteorite finds were made on significantly older sediments (>10 ka). Dense accumulations of meteorites in RaF are found on blowouts of the Pliocene Marsawdad formation. Our combined results show that the proportion of meteorites with low terrestrial ages is low compared to other find areas, consistent with the previously determined high average terrestrial age Oman meteorites and significantly older than suggested by models of exponential decay. Oman meteorites may commonly have been buried within dunes and soils over extended periods, acting as a temporary protection against erosion.

¹Thomas Smith,^1,2,3Huaiyu He,⁴Shijie Li,¹P. M. Ranjith,^1,2Fei Su,⁵Jérôme Gattacceca,⁵Régis Braucher,⁵ASTER-Team
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13760]
¹State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 China
²Institutions of Earth Science, Chinese Academy of Sciences, Beijing, 100029 China
³College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
⁴Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081 China
⁵Centre Européen de Recherche et d’Enseignement de Géosciences de l’Environnement (CEREGE), CNRS, Aix-Marseille University, IRD, INRAE, Aix-en-Provence, France
Published by arrangement with John Wiley

We measured noble gas concentrations and isotopic ratios (He, Ne, and Ar isotopes) in six recent ordinary chondrite falls: Mangui (L6), Viñales (L6), Ozerki (L6), Tamdakht (H5), Kheneg Ljouâd (LL5/6), and Katol (L6). Among them, the three L6 chondrites Mangui, Viñales, and Ozerki fell in only a few months interval; their apparent similar petrographic and mineralogic characteristics might indicate source crater pairing. To test this hypothesis, we have investigated those meteorites for their cosmic ray exposure (CRE) histories, using the cosmogenic noble gases 3He, 21Ne, and 38Ar. We systematically (re)calculated the CRE ages as well as the gas retention ages of these meteorites. The CRE age of the Mangui is, based on noble gases, <1 Ma, which is unusually short for an L chondrite. Indeed, the range of exposure ages for L chondrites is generally distributed between ˜1 and ˜60 Ma, with major peaks occurring around ˜5, ˜30, and ˜40 Ma. In addition, the cosmogenic 3Hecos data of two Mangui duplicates are consistent with a remarkably high loss of helium by diffusion due to heating by solar radiation. Such a short parent body-Earth transfer time (<1 Ma) can be explained by a delivery from an Earth-crossing object. Regarding the other L6 chondrites, Viñales has a nominal CRE age of ˜9.4 Ma, whereas the Ozerki meteorite has a nominal CRE age of ˜1.2 Ma, which is consistent with Korochantseva et al. (2019). Based on their CRE ages as well as on their gas retention ages, it appears that none of these three recent L6 chondrite falls are source crater paired, and therefore, all three originate from different meteoroids. The nominal exposure ages of Tamdakht, Kheneg Ljouâd, and Katol are ˜3.2, ˜11, and ˜30 Ma, respectively, and are consistent with identified age peaks on the exposure age histogram of H, LL, and L chondrites, respectively. The nominal CRE age of Tamdakht is consistent with previous observations for H chondrites and implies that they are dominated by small impact events occurring in several parent bodies.

¹Cyrena Anne Goodrich,^1,2David A. Kring,³Richard C. Greenwood
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13738]
¹Lunar and Planetary Institute, USRA, 3600 Bay Area Blvd, Houston, Texas, 77058 USA
²NASA Solar System Exploration Research Virtual Institute
³Planetary and Space Sciences, The Open University, Milton Keynes, MK76AA UK
Published by arrangement with John Wiley & Sons

Foreign clasts (xenoliths) in meteoritic breccias are a serendipitous source of information about the impact environment in which their hosts formed, including impactor flux and cosmochemical types. These parameters may be related to timing and/or heliocentric distance of xenolith origin and implantation, and thus can be used to test or inform models of early solar system dynamics. We use xenoliths in ordinary chondrites (OCs) and ureilites to do this. We first conducted a petrologic and oxygen isotope study of a new, cm-sized igneous-textured clast in L3.7 Northwest Africa (NWA) 092, which highlighted some of the difficulties of identifying xenoliths in meteorites. Results indicate that this clast is not a xenolith but an impact melt of non-local OC material. We add this result to a literature survey of more than 3000 OCs and find that the fraction of OCs that contain xenoliths is <<1%, and, even in these, the abundance and the diversity of xenoliths are very low. This contrasts markedly with the ureilites, ˜5% of which contain ˜1–10 vol% xenoliths from every major meteorite class, including multiple groups and petrologic types. To investigate reasons for this difference, we compare the histories of OC and ureilite parent bodies. The OC and ureilitic parent bodies accreted in the inner solar system within ˜1 AU of one another. The OC bodies accreted ˜2–3 Myr after calcium-aluminum-rich inclusion (CAI) formation and were heated slowly, experiencing thermal metamorphism over ˜50–60 Myr. The ureilite parent body (UPB) accreted <1 Myr after CAIs and was heated rapidly, experiencing partial melting over ˜4 Myr. Both OC parent bodies and the UPB were catastrophically disrupted and reassembled into rubble piles. For ureilites, this occurred ˜5.0–5.4 Ma after CAIs, while for OCs, it did not occur until 50–60 Myr after CAIs. Xenoliths in OC and ureilitic breccias were acquired as fragments of impactors on the rubble piles. The presence in polymict ureilites of xenoliths of all OC groups (H, L, LL) and petrologic types (3–6), and the intimate scale on which these and myriad other xenolith types are mixed, indicate that most xenoliths were acquired within a short time period around ˜50–60 Myr after CAIs when OC (likely also Rumuruti chondrite and enstatite chondrite) parent bodies were disrupted. This timing is consistent with the early instability dynamical model for a period of excitation in the asteroid belt. Outer solar system (CC) xenoliths were also acquired during this period, but were derived indirectly from C-type bodies that had already been emplaced in orbits in the asteroid belt. The large discrepancy in xenolith abundance between ureilites and OC may be due to different physical properties of their regoliths at 50–60 Myr after CAIs. CC-like xenoliths in OC may represent a different, more recently acquired, population than those in polymict ureilites.

¹Evelyn Füri,¹Laurent Zimmermann,²Harald Hiesinger
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13749]
¹Institut für Planetologie, Westfälische Wilhelms-Universität, Münster, D-48149 GermanyCNRS, CRPG, Université de Lorraine, Nancy, F-54000 France
²Institut für Planetologie, Westfälische Wilhelms-Universität, Münster, D-48149 Germany
Published by arrangement with John Wiley & Sons

Cosmic ray exposure (CRE) ages of rocks that were ejected by the impacts that created Cone and North Ray craters provide two crucial calibration points at <100 Ma for the lunar cratering chronology function, which relates the crater density of geological units on the Moon to their absolute age. To reassess the formation ages of these two craters, we determine here the accumulated abundances of “cosmogenic” noble gas nuclides (3Hecosm, 21Necosm, 38Arcosm), as well as the corresponding CRE ages, in six Apollo 14 rocks (i.e., one breccia and five basalts) and two Apollo 16 anorthosites that were collected near the rims of Cone and North Ray craters, respectively. Although noble gas concentrations allow CRE ages to be derived, the calculated 21Ne and 38Ar exposure ages of a given sample cover a significant range of values because published empirical or theoretical production rates of cosmogenic nuclides are highly variable. Nonetheless, it is evident that mare basalts 14053 and 14072 as well as breccia 14068, which were collected near the rim of Cone crater, were exposed at the lunar surface more recently than the three KREEP basalts (14073, 14077, 14078) collected farther away. The 38Ar exposure ages of anorthosites 67075 and 67955 from North Ray crater slightly exceed those of samples 14053, 14068, and 14072. These results confirm that Cone crater is younger than North Ray crater. However, the formation ages of Cone and North Ray craters have larger uncertainties than previously acknowledged. This implies that the uncertainties of noble gas exposure ages should be taken into account when remotely dating young surfaces on the Moon and on other planetary bodies in the solar system.

¹Yanhao Lin,^1,2Wim van Westrenen,¹Ho-Kwang Mao
Proceedings of the National Academy of the United States of America (PNAS) 118, e2110427118 Link to Article [https://doi.org/10.1073/pnas.2110427118]
¹Center for High Pressure Science and Technology Advanced Research, Beijing 100094, People’s Republic of China;
²Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands

Refractory oxygen bound to cations is a key component of the interior of rocky exoplanets. Its abundance controls planetary properties including metallic core fraction, core composition, and mantle and crust mineralogy. Interior oxygen abundance, quantified with the oxygen fugacity (fO2), also determines the speciation of volatile species during planetary outgassing, affecting the composition of the atmosphere. Although melting drives planetary differentiation into core, mantle, crust, and atmosphere, the effect of fO2 on rock melting has not been studied directly to date, with prior efforts focusing on fO2-induced changes in the valence ratio of transition metals (particularly iron) in minerals and magma. Here, melting experiments were performed using a synthetic iron-free basalt at oxygen levels representing reducing (log fO2 = −11.5 and −7) and oxidizing (log fO2 = −0.7) interior conditions observed in our solar system. Results show that the liquidus of iron-free basalt at a pressure of 1 atm is lowered by 105 ± 10 °C over an 11 log fO2 units increase in oxygen abundance. This effect is comparable in size to the well-known enhanced melting of rocks by the addition of H2O or CO2. This implies that refractory oxygen abundance can directly control exoplanetary differentiation dynamics by affecting the conditions under which magmatism occurs, even in the absence of iron or volatiles. Exoplanets with a high refractory oxygen abundance exhibit more extensive and longer duration magmatic activity, leading to more efficient and more massive volcanic outgassing of more oxidized gas species than comparable exoplanets with a lower rock fO2.

¹Aleksandr A. Zubov,¹Tatyana G. Shumilova,¹Andrey V. Zhuravlev,¹Sergey I. Isaenko
American Mineralogist 106, 1860-1870 Link to Article [http://www.minsocam.org/msa/ammin/toc/2021/Abstracts/AM106P1860.pdf]
¹Institute of Geology of Komi Science Center of the Ural Branch of the Russian Academy of Sciences, Pervomayskaya st. 54, Syktyvkar, 167982, Russia
Copyright: The Mineralogical Society of America

X‑ray computed microtomography (CT) of impact rock varieties from the Kara astrobleme is used to test the method’s ability to identify the morphology and distribution of the rock components. Three types of suevitic breccias, clast‑poor melt rock, and a melt clast from a suevite were studied with a spatial resolution of 24 μm to assess CT data values of 3D structure and components of the impactites.
The purpose is first to reconstruct pore space, morphology, and distribution of all distinguishable
crystallized melt, clastic components, and carbon products of impact metamorphism, including the impact glasses, after‑coal diamonds, and other carbon phases. Second, the data are applied to analyze
the morphology and distribution of aluminosilicate and sulfide components in the melt and suevitic
breccias. The technical limitations of the CT measurements applied to the Kara impactites are discussed. Because of the similar chemical composition of the aluminosilicate matrix, glasses, and some lithic and crystal clasts, these components are hard to distinguish in tomograms. The carbonaceous matter has absorption characteristics close to air, so the pores and carbonaceous inclusions appear similar.
However, X‑ray microtomography could be used to prove the differences between the studied types
of suevites from the Kara astrobleme using structural‑textural features of the whole rock, porosity,
and the distributions of carbonates and sulfides.

^1,2Laurence A.J. Garvie,³Chi Ma,²Soumya Ray,⁴Kenneth Domanik,⁵Axel Wittmann,²Meenakshi Wadhwa
American Mineralogist 106, 1828-1834 Link to Article [http://www.minsocam.org/msa/ammin/toc/2021/Abstracts/AM106P1828.pdf]
¹Center for Meteorite Studies, Arizona State University, 781 East Terrace Road, Tempe, Arizona 85287-6004, U.S.A.
²School of Earth and Space Exploration, Arizona State University, 781 East Terrace Road, Tempe, Arizona 85287-6004, U.S.A.
³Division of Geological and Planetary Sciences, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, U.S.A.
⁴Lunar and Planetary Laboratory, University of Arizona, 1415 N 6th Avenue, Tucson, Arizona 85705, U.S.A.5Eyring Materials Center, Arizona State University, Tempe, Arizona 85287, U.S.A.
Copyright: The Mineralogical Society of America

Carletonmooreite (IMA 2018-68), Ni3Si, is a new nickel silicide mineral that occurs in metal nodules from the Norton County aubrite meteorite. These nodules are dominated by low-Ni iron (kamacite), with accessory schreibersite, nickelphosphide, perryite, and minor daubréelite, tetratae-nite, taenite, and graphite. The chemical composition of the holotype carletonmooreite determined by wavelength-dispersive electron-microprobe analysis is (wt%) Ni 82.8 ± 0.4, Fe 4.92 ± 0.09, and Si 13.08 ± 0.08 (n = 6, total = 100.81) giving an empirical formula of (Ni2.87Fe0.18)Σ3.05Si0.95, with an end-member formula of Ni3Si. Further grains discovered in the specimen after the new mineral submission extend the composition, i.e., (wt%) Ni 81.44 ± 0.82, Fe 5.92 ± 0.93, Cu 0.13 ± 0.02, and Si 13.01 ± 0.1 (n = 11, total = 100.51 ± 0.41), giving an empirical formula (Ni2.83Fe0.22Cu0.004)Σ3.05Si0.95. The backscat-
tered electron-diffraction patterns were indexed by the Pm3m auricupride (AuCu3)-type structure and
give a best fit to synthetic Ni3Si, with a = 3.51(1) Å, V = 43.2(4) Å3, Z = 1, and calculated density of
7.89 g/cm3. Carletonmooreite is silver colored with an orange tinge, isotropic, with a metallic luster and occurs as euhedral to subhedral crystals 1 × 5 μm to 5 × 14 μm growing on tetrataenite into kamacite. The dominant silicide in the Norton County aubrite metal nodules is perryite (Ni,Fe)8(Si,P)3, with
carletonmooreite restricted to localized growth on rare plessite fields. The isolated nature of small euhedral carletonmooreite single crystals suggests low-temperature growth via solid-state diffusion
from the surrounding kamacite and epitaxial growth on the tetrataenite. This new mineral is named in honor of Carleton B. Moore, chemist and geologist, and founding director of the Center for Meteorite Studies at Arizona State University, for his many contributions to cosmochemistry and meteoritics.