¹Nicole X. Nie,^1,2Da Wang,¹Zachary A. Torrano,¹Richard W. Carlson,¹Conel M. O’D. Alexander,¹Anat Shahar
Science 379, 6630 Link to Article [DOI: 10.1126/science.abn178]
¹Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA.
²International Center for Planetary Science, College of Earth Sciences, Chengdu University of Technology, 610059 Chengdu, China.
Reprinted with permission from AAAS

Meteorites record processes that occurred before and during the formation of the Solar System in the form of nucleosynthetic anomalies: isotopic compositions that differ from the Solar System patterns. Nucleosynthetic anomalies are rarely seen in volatile elements such as potassium at bulk meteorite scale. We measured potassium isotope ratios in 32 meteorites and identified nucleosynthetic anomalies in the isotope potassium-40. The anomalies are larger and more variable in carbonaceous chondrite (CC) meteorites than in noncarbonaceous (NC) meteorites, indicating that CCs inherited more material produced in supernova nucleosynthesis. The potassium-40 anomaly of Earth is close to that of the NCs, implying that Earth’s potassium was mostly delivered by NCs.

¹Rayssa Martins,¹Sven Kuthning,¹Barry J. Coles,¹Katharina Kreissig,¹Mark Rehkämper
Science 379, 6630 Link to Article [DOI: 10.1126/science.abn1021]
¹Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK.
Reprinted with permission from AAAS

Material inherited from different nucleosynthesis sources imparts distinct isotopic signatures to meteorites and terrestrial planets. These nucleosynthetic isotope anomalies have been used to constrain the origins of material that formed Earth. However, anomalies have only been identified for elements with high condensation temperatures, leaving the origin of Earth’s volatile elements unconstrained. We determined the isotope composition of the moderately volatile element zinc in 18 bulk meteorites and identified nucleosynthetic zinc isotope anomalies. Using a mass-balance model, we find that carbonaceous bodies, which likely formed beyond the orbit of Jupiter, delivered about half of Earth’s zinc inventory. Combined with previous constraints obtained from studies of other elements, these results indicate that ~10% of Earth’s mass was provided by carbonaceous material.

¹Daniele Fulvio,¹Ciprian Popa,¹Vito Mennella,²Federico Tosi,²SimoneDe Angelis,²Mauro Ciarniello,²Alessandro Mura,²Gianrico Filacchione
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2023.115444]
¹INAF, Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, Naples 80131, Italy
²INAF, Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, Rome 00133, Italy
Copyright Elsevier

Hydrated salts are thought to be a surface component of many different solid bodies in the solar system such as the icy-world satellites, especially the large ones of Jupiter and Saturn. In this context, three hydrated salts of interest in planetary sciences – natron (Na2CO3·10H2O), mirabilite (Na2SO4·10H2O), and epsomite (MgSO4·7H2O) – were selected and their NIR (0.8–3.6 μm) reflectance properties were studied as a function of temperature after diluting them in water. The main goal of these experiments is to characterize the evolution induced in the hydrated salt NIR spectra by the mixing and melting with water followed by freezing of the samples down to 95 K. Our results show that mixing of hydrated salts with water induces a complex phenomenology characterized by the formation of new bonds and absorption features. In addition, the shape and minimum position of the NIR spectral features here analyzed are temperature-dependent. The present laboratory study will be extremely useful to interpret the high-resolution data of Jupiter’s icy satellites surfaces which will be available in the next future thanks to the MISE and MAJIS instruments aboard NASA Europa Clipper and ESA JUICE spacecraft, respectively.

¹M.W.Broadley et al. (>10)
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2023.01.020]
¹Université de Lorraine, CNRS, CRPG
Copyright Elsevier

Carbonaceous chondrites are considered to have originated from C-type asteroids and represent some of the most primitive material in our solar system. Furthermore, since carbonaceous chondrites can contain significant quantities of volatile elements, they may have played a crucial role in supplying volatiles and organic material to Earth and other inner solar system bodies. However, a major challenge of unravelling the volatile composition of chondritic meteorites is distinguishing between which features were inherited from the parent body, and what may be a secondary feature attributable to terrestrial weathering. In December 2020, the Hayabusa2 mission of the Japan Aerospace Exploration Agency (JAXA) successfully returned surface material from the C-type asteroid (162173) Ryugu to Earth. This material has now been classified as closely resembling CI-type chondrites, which are the most chemically pristine meteorites. The analysis of material from the surface of Ryugu therefore provides a unique opportunity to analyse the volatile composition of material that originated from a CI-type asteroid without the complications arising from terrestrial contamination. Given their highly volatile nature, the noble gas and nitrogen inventories of chondrites are highly sensitive to different alteration processes on the asteroid parent body, and to terrestrial contamination. Here, we investigate the nitrogen and noble gas signature of two pelletized grains collected from the first and second touchdown sites (Okazaki et al., 2022a), to provide an insight into the formation and alteration history of Ryugu. The concentration of trapped noble gas in the Ryugu samples is greater than the average composition of previously measured CI chondrites and are primarily derived from phase Q, although a significant contribution of presolar nanodiamond Xe-HL is noted. The large noble gas concentrations coupled with a significant contribution of presolar nanodiamonds suggests that the Ryugu samples may represent some of the most primitive unprocessed material from the early solar system. In contrast to the noble gases, the abundance of nitrogen and δ15N composition of the two Ryugu pellets are lower than the average CI chondrite value. We attribute the lower nitrogen abundances and δ15N measured in this study to the preferential loss of a 15N-rich phase from our samples during aqueous alteration on the parent planetesimal. The analyses of other grains returned from Ryugu have shown large variations in nitrogen concentrations and δ15N indicating that alteration fluids heterogeneously interacted with material now present on the surface of Ryugu. Finally, the ratio of trapped noble gases to nitrogen is higher than CI chondrites, and is closer to refractory phase Q and nanodiamonds. This indicates that Ryugu experienced aqueous alteration that led to the significant and variable loss of nitrogen, likely from soluble organic matter, without modification of the noble gas budget, which is primarily hosted in insoluble organic matter and presolar diamonds and is therefore more resistant to aqueous alteration.

¹Jesse Reimink,²Carolyn Crow,³Desmond Moser,⁴Benjamin Jacobsen,⁵Ann Bauer,⁶Thomas Chacko
Earth and Planetary Science Letters 604, 118007 Link to Article [https://doi.org/10.1016/j.epsl.2023.118007]
¹Department of Geosciences, Penn State University, PA, 16802, USA
²Department of Geological Sciences, CU Boulder, CO, 80309, USA
³Department of Earth Sciences, University of Western Ontario, Ontario, N6A 3K7, Canada
⁴Nuclear and Chemical Science Division, Lawrence Livermore National Laboratory, 94550, USA
⁵Department of Geoscience, University of Wisconsin, WI, 53706, USA
⁶Department of Earth and Atmospheric Science, University of Alberta, Alberta, T6G 2E3, Canada
Copyright Elsevier

The first 500 million years of Earth history is thought to be a period of intense planetary bombardment, but the timing and flux of this meteorite bombardment is poorly understood. In particular, on the basis of an inferred lunar impact history, some workers have hypothesized a ∼3.9 Ga terminal cataclysm (TC) in which there was marked increase in the impact flux affecting the Moon, the Earth and possibly other terrestrial planets. Minerals that survived this enigmatic period offer a way to test early planetary bombardment models as they may contain telltale micro- to nanoscale shock features. Here, we present results from a numerical modeling calculation that assesses the probability that a zircon residing in the crust would escape shock melting or shock deformation during a TC bombardment event. Even with conservative pressure estimates for zircon shock deformation and intermediate bombardment intensities, we find that only ∼6% of ≥4.0 Ga crust would be expected to survive a 3.9 Ga cataclysm without experiencing either complete melting or zircon shock metamorphism. We couple this modeling with a search for shock effects in the oldest zircons from the Acasta Gneiss Complex, which would have been present in the Earth’s crust during a putative 3.9 Ga TC. Spatially correlated electron and NanoSIMS ion microscopy of 4.02 Ga igneous zircons from Acasta reveals no evidence of ancient shock. These data, together with similar results from other Hadean zircon suites, confirm that a post-Hadean TC is unlikely to have occurred. We suggest that the dearth of pre-3.9 Ga terrestrial crust and zircons is instead best explained by endogenic processes related to the mechanisms of early crust formation. Our modeling allows us to evaluate bombardment scenarios from the terrestrial zircon record by applying probabilistic interpretations to zircon shock deformation data. This approach will be valuable for other planetary bodies, allowing broader conclusions to be drawn from geographically limited datasets.

¹Marina Martínez,^1,2Charles K.Shearer,¹Adrian J.Brearley
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2023.01.016]
¹Department of Earth & Planetary Sciences, MSC03-2040, 1University of New Mexico, Albuquerque, NM 87131, USA
²Institute of Meteoritics, MSC03-2040, University of New Mexico, Albuquerque, NM 87131, USA
Copyright Elsevier

Melt inclusions are of major significance because they can constrain the volatile abundances in magmas. Here, we report the discovery of the first melt inclusion in a martian apatite containing the first chloro-amphibole reported in Northwest Africa (NWA) 998, a sample that crystallized early from the nakhlite-source. The amphibole is also the first sodic-calcic amphibole in a nakhlite, identified as ferro-chloro-winchite (4.75 wt% Cl) by FIB-TEM. The melt inclusion is present in a euhedral, cumulus apatite grain (Cl/F = 2.11) and is surrounded by a shell of voids. Evidence indicates that the melt inclusion remained as a closed system although syn- and post-entrapment processes may have modified the chemical composition of the original trapped melt. The inclusion also contains Fe-rich, Ca-poor pyroxene and a residual silicate melt consisting of pyroxene and interstitial K-rich glass. Additionally, Cl-enriched apatite is present within the boundaries of the melt inclusion. This apatite could result from cracking of host-apatite during contraction of the melt inclusion glass or represent daughter apatite crystallizing on the walls of the inclusion. Given that Cl-enrichments are found in the host apatite outside the melt inclusion, it is inferred that a later, fluid alteration event locally modified the composition of the apatite in and/or around the melt inclusion. The calculated bulk composition of the melt inclusion is generally consistent with previous work in other nakhlites. Prior to this study, Cl-rich amphiboles have only been found within olivine- and pyroxene-hosted melt inclusions in the later-formed nakhlites. The present study thus demonstrates that (i) the nakhlites record magmatic mixing with a Cl-rich exogenous component that is absent within olivine-hosted melt inclusions in the chassignites, (ii) Cl-rich amphiboles were able to crystallize from the earliest nakhlite parent melt, and (iii) the presence of a Cl-rich fluid was not required to stabilize chloro-amphiboles. We also conclude that magmatic martian amphiboles likely stabilized at lower pressures (and temperatures) than terrestrial amphiboles due to their higher Cl contents.

^1,2C.Deligny,¹E.Füri,¹E.Deloule,^3,4A.H.Peslier,¹F.Faure,¹Y.Marrocchi
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2023.01.017]
¹Université de Lorraine, CNRS, CRPG, F-54000 Nancy, France
²Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden1
³Jacobs, NASA-Johnson Space Center, Mail Code X13, Houston, TX 77058, USA
⁴Dept. of Geological Sciences, New Mexico State University, Las Cruces, NM 88011, USA
Copyright Elsevier

Martian meteorites are key for assessing the isotopic characteristics of nitrogen in different martian reservoirs (i.e., mantle, crust, and atmosphere), and, ultimately, for constraining the source(s) of nitrogen trapped during the earliest stages of planetary accretion in the terrestrial planet-forming region. In this study, we analysed, for the first time, the nitrogen content and isotopic composition of glassy melt inclusions of Chassigny and of the mesostasis of five nakhlites (MIL 03346, Nakhla, NWA 6148, NWA 998, and Y 000593) by in situ secondary ion mass spectrometry. The nitrogen content of Chassigny melt inclusions, corrected for olivine overgrowth on the inclusion walls, varies from 4 ± 1 to 860 ± 45 ppm N, and the majority of δ15N values range from –35 ± 41 to +73 ± 36‰. The estimated nitrogen isotopic signature of the primitive melt, prior to degassing of N2 or NH3, is 0 ± 32‰. The mesostasis of nakhlites contains 2.7 ± 0.2 to 943 ± 156 ppm N, with δ15N values from –30 ± 37 to +348 ± 43‰. Whereas degassing of N2 or NH3 can explain the lowest nitrogen isotopic ratios measured in the nakhlite mesostasis, the 15N-enriched isotopic composition (δ15N > 150‰) of four nakhlites (MIL 03346, Nakhla, NWA 6148, and Y 000593) likely results from interaction of the mesostasis melt with the martian atmosphere during ejection. The δ15N values (+25 ± 42 and +77 ± 19‰) of two melt inclusions in Y 000593 are comparable to those of Chassigny, further confirming that these meteorites likely sample a common volatile reservoir in the martian interior. Overall, the new results indicate that the chassignite-nakhlite reservoir did not inherit nitrogen from the solar nebula but, instead, from chondritic-like materials. These findings further confirm that planetary bodies in the inner solar system accreted (isotopically) chondritic nitrogen during the first few million years of solar system history.

¹S.A.Singerling,^2,5L.R.Nittler,²J.Barosch,³E.Dobrică,⁴A.J.Brearley,^1,5R.M.Stroud
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2023.01.015]
¹U.S. Naval Research Laboratory, Code 6366, Washington, DC 20375, USA
²Carnegie Institution of Washington, Washington, DC 20015, USA
³University of Hawai’i at Mānoa, Honolulu, HI 96822, USA
⁴University of New Mexico, Albuquerque, NM 87131, USA
⁵Arizona State University, Tempe, AZ 85287, USA
Copyright Elsevier

We conducted a transmission electron microscopy (TEM) study of an unusual oxide-silicate composite presolar grain (F2-8) from the unequilibrated ordinary chondrite Semarkona (LL3.00). The presolar composite grain is relatively large (>1 µm), has an amoeboidal shape, and contains Mg-rich olivine (forsterite), Mg-Al spinel, and Ca-rich pyroxene. The shape and phase assemblage are reminiscent of amoeboid-olivine-aggregates (AOAs) and add to the growing number of TEM observations of presolar refractory inclusion-like (CAIs and AOAs) grains. In addition to the dominant components, F2-8 also contains multiple subgrains, including an alabandite-oldhamite composite grain within the olivine and several magnetite subgrains within the Mg-Al spinel. We argue that the olivine, Mg-Al spinel, and alabandite-oldhamite formed by equilibrium condensation, whereas the Ca-rich pyroxene formed by non-equilibrium condensation, all in an M-type AGB star envelope. On the other hand, the magnetite subgrains are likely the result of aqueous alteration on the Semarkona asteroidal parent body. Additional evidence of secondary processing includes Fe-enrichment in the Mg-Al spinel and olivine, elevated Al contents in the olivine, and beam sensitivity and a modulated structure for the olivine.

Compound presolar grains, in particular oxide-silicate AOA-like grains such as F2-8, record condensation conditions over a wide range of temperatures. Additionally, the presence of several different presolar phases in a composite grain can impart information on the relative rates and effects of post-condensation processing in a range of environments, including the interstellar medium, solar nebula, and the host asteroid parent body. For example, the olivine and spinel in F2-8 show evidence of fluid infiltration, but each component reacted in different ways and to different extents. The TEM observations of F2-8 provide insights across the lifetime of the grain from its formation by condensation in an M-type AGB star envelope, its transit through the interstellar medium, and aqueous alteration during its residence on Semarkona’s asteroidal parent body.

¹E. Clavé et al. (>10)
Journal of Geophysical research (Planets) Link to Article [https://doi.org/10.1029/2022JE007463]
¹CELIA, Université de Bordeaux, CNRS, CEA, Bordeaux, France
Published by arrangement with John Wiley & Sons

Perseverance explored two geological units on the floor of Jezero Crater over the first 420 Martian days of the Mars2020 mission. These units, the Máaz and Séítah formations, are interpreted to be igneous in origin, with traces of alteration. We report the detection of carbonate phases along the rover traverse based on laser-induced breakdown spectroscopy (LIBS), infrared reflectance spectroscopy (IRS), and time-resolved Raman (TRR) spectroscopy by the SuperCam instrument. Carbonates are identified through direct detection of vibrational modes of CO3 functional groups (IRS and TRR), major oxides content, and ratios of C and O signal intensities (LIBS). In Séítah, the carbonates are consistent with magnesite-siderite solid solutions (Mg# of 0.42-0.70) with low calcium contents (<5 wt.% CaO). They are detected together with olivine in IRS and TRR spectra. LIBS and IRS also indicate a spatial association of the carbonates with clays. Carbonates in Máaz are detected in fewer points, as: (i) siderite (Mg# as low as 0.03); (ii) carbonate-containing coatings, enriched in Mg (Mg# ∼0.82) and spatially associated with different salts. Overall, using conservative criteria, carbonate detections are rare in LIBS (∼30/2000 points), IRS (∼15/2000 points), and TRR (1 /150 points) data. This is best explained by (i) a low carbonate content overall, (ii) small carbonate grains mixed with other phases, (iii) intrinsic complexity of in situ measurements. This is consistent with orbital observations of Jezero crater, and similar to compositions of carbonates previously reported in Martian meteorites. This suggests a limited carbonation of Jezero rocks by locally equilibrated fluids.

¹L.Mandon et al. (>10)
Journal of Geophysical research (Planets) Link to Article [https://doi.org/10.1029/2022JE007450]
¹LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, Meudon, France
Published by arrangement with John Wiley & Sons

The Perseverance rover landed in the ancient lakebed of Jezero crater, Mars on February 2021. Here we assess the mineralogy of the rocks, regolith, and dust measured during the first year of the mission on the crater floor, using the visible and near-infrared spectrometer of SuperCam onboard the Perseverance rover. Most of the minerals detected from orbit are present in the bedrock, with olivine-bearing rocks at the bottom of the stratigraphy and high-Ca pyroxene-bearing rocks at the top. This is distinct from the overall low-Ca pyroxene-bearing composition of the watershed of Jezero, and points towards an igneous origin. Alteration mineral phases were detected in most of the rocks analyzed in low proportions, suggesting that aqueous alteration of the crater floor has been spatially widespread, but limited in intensity and/or time. The diverse aqueous mineralogy suggests that the aqueous alteration history of the crater floor consists of at least two stages, to form phyllosilicates and oxyhydroxides, and later sulfates. We interpret their formation in a lake or under deeper serpentinization conditions, and in an evaporative environment, respectively. Spectral similarities of dust with some rock coatings suggest widespread past processes of dust induration under liquid water activity late in the history of Jezero. Analysis of the regolith revealed some local inputs from the surrounding rocks. Relevant to the Mars Sample Return mission, the spectral features exhibited by the rocks sampled on the crater floor are representative of the diversity of spectra measured on the geological units investigated by the rover.