¹Addi Bischoff et al.(>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14245]
¹Institut für Planetologie, University of Münster, Münster, Germany
Published by arrangement with John Wiley & Sons

n 1889 the German poet and novelist Theodor Fontane wrote the popular literary ballad “Herr von Ribbeck auf Ribbeck im Havelland.” The Squire von Ribbeck is described as a gentle and generous person, who often gives away pears from his pear trees to children passing by and continued donating pears after his death. Now, 135 years later the rock called Ribbeck is giving us insight into processes that happened 4.5 billion years ago. The meteorite Ribbeck (official find location: 52°37′15″N, 12°45′40″E) fell January 21, 2024, and has been classified as a brecciated aubrite. This meteoroid actually entered the Earth’s atmosphere at 00:32:38 UTC over Brandenburg, west of Berlin, and the corresponding fireball was recorded by professional all sky and video cameras. More than 200 pieces (two proved by radionuclide analysis to belong to this fresh fall) were recovered totaling about 1.8 kg. Long-lived radionuclide and noble gas data are consistent with long cosmic ray exposure (55–62 Ma) and a preatmospheric radius of Ribbeck between 20 and 30 cm. The heavily brecciated aubrite consists of major (76 ± 3 vol%) coarse-grained FeO-free enstatite (En99.1Fs<0.04Wo0.9), with a significant abundance (15.0 ± 2.5 vol%) of albitic plagioclase (Ab95.3 An2.0Or2.7), minor forsterite (5.5 ± 1.5 vol%; Fo99.9) and 3.5 ± 1.0 vol% of opaque phases (mainly sulfides and metals) with traces of nearly FeO-free diopside (En53.2Wo46.8) and K-feldspar (Ab4.6Or95.4). The rock has a shock degree of S3 (U-S3), and terrestrial weathering has affected metals and sulfides, resulting in the brownish appearance of rock pieces and the partial destruction of certain sulfides already within days after the fall. The bulk chemical data confirm the feldspar-bearing aubritic composition. Ribbeck is closely related to the aubrite Bishopville. Ribbeck does not contain solar wind implanted gases and is a fragmental breccia. Concerning the Ti- and O-isotope compositions, the data are similar to those of other aubrites. They are also similar to E chondrites and fall close to the data point for the bulk silicate Earth (BSE). Before the Ribbeck meteoroid entered Earth’s atmosphere, it was observed in space as asteroid 2024 BX1. The aphelion distance of 2024 BX1’s orbit lies in the innermost region of the asteroid belt, which is populated by the Hungaria family of minor planets characterized by their E/X-type taxonomy and considered as the likely source of aubrites. The spectral comparison of an average large-scale emission spectrum of Mercury converted into reflectance and of the Ribbeck meteorite spectrum does not show any meaningful similarities.

¹E. V. Petrova,¹A. V. Chukin,²G. Varga,²Z. Dankházi,³G. Leitus,⁴I. Felner,⁵E. Kuzmann,⁵Z. Homonnay,¹V. I. Grokhovsky,¹M. I. Oshtrakh
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14249]
¹Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russian Federation
²Department of Materials Physics, Eötvös Loránd University, Budapest, Hungary
³Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
⁴Racah Institute of Physics, The Hebrew University, Jerusalem, Israel
⁵Laboratory of Nuclear Chemistry, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary
Published by arrangement with John Wiley & Sons

Fragment of Calama 009 L6 ordinary chondrite recovered in the Atacama Desert was chosen for a complex study of the bulk interior and the fusion crust by scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), magnetization measurements, and Mössbauer spectroscopy. SEM demonstrated the presence of Fe-Ni-Co grains, troilite and chromite inclusions in both the bulk interior and the fusion crust as well as many veins with ferric compound. EDS showed variations in the Ni concentration within the metal grains and within one metal phase in the grain. XRD revealed some differences in the contents of various phases in the bulk interior and in the fusion crust. XRD indicated the presence of magnesioferrite in the fusion crust as well as the formation of goethite nanoparticles with the mean size of 9 nm in both the bulk interior and the fusion crust. Magnetization measurements demonstrated the ferrimagnetic–paramagnetic phase transition in chromite at 44 K and low values of the saturation magnetization moments (6.46 and 3.26 emu g−1 at 100 K) for the bulk interior and the fusion crust, respectively, due to the lack of Fe-Ni-Co alloy as a result of weathering. The Mössbauer spectra of the bulk interior and the fusion crust showed some differences in the number and relative areas of spectral components. The revealing of the Mössbauer spectral components related to 57Fe in the M1 and M2 sites in olivine and orthopyroxene as well as determining the Fe2+ occupations of these sites from XRD permitted us to estimate the temperature of equilibrium cation distribution for these silicates which are (i) 662 K (XRD) and 706 K (Mössbauer spectroscopy) for olivine and (ii) 893 K (XRD) and 910 K (Mössbauer spectroscopy) for orthopyroxene.

¹Daniela Guerrero,¹Wolf Uwe Reimold,¹Natalia Hauser,²Igor Figueiredo,²Lucas Kenni,³Philippe Lambert
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14247]
¹Postgraduate Program in Geology, Laboratory of Geochronology, Geosciences Institute, University of Brasília, Brasília, Brazil
²Department of Geology—Escola de Minas, Federal University of Ouro Preto, Ouro Preto, Brazil
³CIRIR—Centre International de Recherche et de Restitution sur les Impacts et sur Rochechouart, Rochechouart, France
Published by arrangement with John Wiley & Sons

The Rochechouart impact structure in the northwestern part of the French Massif Central (FMC) has a great diversity of impactites, including monomict impact breccias, suevite, and impact melt rocks (IMRs). The structure is strongly eroded, which allows the study of impactites of the crater fill and the transition into the crater floor. The FMC has had a multistage geological evolution from the late Neoproterozoic to the Ordovician (600–450 Ma) until the later stages of the Variscan orogeny (~300 Ma). Previous geochronological work on Rochechouart has been focused mainly on the impactites and constraining the impact age, and scarce work has been done on the FMC-related target rocks. Here, U-Pb isotope analysis by LA-MC-ICP-MS has been conducted on zircon from two IMRs from the Recoudert and Montoume localities, and from a monzodiorite, a paragneiss, and two amphibolite samples of the basement to the impact structure. Zircon from the target rocks yielded mainly Neoproterozoic to Carboniferous ages (~924 to ~301 Ma) that can mostly be correlated to different stages of the geological evolution of the FMC. The monzodiorite also yielded a Permian age of 272 ± 12 Ma. Zircon from the IMRs, and especially from the Montoume sample, gave a comparatively higher diversity of Neoproterozoic to Jurassic ages (~552 to ~195 Ma). Provenance analysis for the zircon age populations of the impactites compared to those of the basement rocks shows overall poor correlation between the two age groups. This suggests that other target lithologies were involved in the formation of these impact melts as well. Post-Variscan and preimpact ages (281–226 Ma) obtained for both melt rocks probably reflect a previously unconstrained event in the evolution of the regional geological history. Ages similar to the currently most widely accepted impact age of ~204–206 Ma were obtained from both IMR samples. In addition, the Montoume melt rock yielded several post-204 Ma ages, which might reflect a to date unconstrained, about 194 Ma postimpact thermal/hydrothermal event.

¹Carolinna da Silva Maia de Souza,¹Natalia Hauser,¹Wolf Uwe Reimold,¹Renato Borges Bernardes,¹Lucieth Cruz Vieira,¹Edi Mendes Guimarães,²Manfred Gottwald
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14236]
¹Institute of Geosciences, University of Brasilia, Darcy Ribeiro Campus, Brasília, Brazil
²German Aerospace Center, Remote Sensing Technology Institute, Wessling, Germany
Published by arrangement with John Wiley & Sons

Extensive, new outcrops along the MT-100 state road in the northern part of the central uplift of the 40-km diameter, 252–259 Ma old Araguainha impact structure, Central Brazil, have become available for investigation. They offer new insight into the contact relationships between the different lithologies and the genesis of different types of impact-related rocks, as well as the current level of erosion of the structure. Three types of impact melt rock (IMR) with different field relationships and compositions can now be distinguished: (1) Type-I of granitic composition and occurring mainly as veins and dikes, besides a few larger pods, in the central alkali granite core of the central uplift; (2) Type-II in the form of plastically deformed clasts of mainly highly silicious compositions in polymict impact breccia; and (3) Type-III, derived from partially melted conglomerate or sandstone precursors, and that occurs at selected sites in (meta)sedimentary strata of the basement in the immediate environs of the alkali granite core. Both polymict lithic and melt-bearing (suevitic) impact breccias are recognized in the 110-m thick integrated section through impact breccia directly overlying the crater floor. This crater floor is composed of (meta)-sedimentary basement strata with granite injections and, locally, sandstones of the Devonian sedimentary Furnas Formation of the Paraná Basin. Main breccia components are (meta)-pelites and (meta)sandstones of the basement that is currently favored to be related to the regional Paraguay Belt and to the lower sequence of the Paraná Basin sedimentary strata. Locally, breccia contains clasts of IMR Type-II, and only very rarely are granitic fragments observed. Clasts of IMR Type-I have never been observed in the breccia deposits. These new observations preclude significant involvement of alkali granite in the formation of the polymict breccia or in the production of shock melts. They also reveal the major role of the (meta)sedimentary precursors in the production of IMR by shock melting and provide essential information for better understanding the cratering processes involved in the formation of an impact structure in a sedimentary target, of the size of the Araguainha impact structure.

^1,2Aryavart Anand et al. (>10)
Geochimica et Cosmochimica acta (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gca.2024.07.025]
¹Max Planck Institute for Solar System Research, Göttingen 37077, Germany
²Institut für Geologie, Universität Bern, Bern 3012, Switzerland
Copyright Elsevier

Magmatic iron meteorites are thought to sample the metallic cores of differentiated planetesimals and are subdivided into several chemical groups, each representing a distinct parent body. The only exceptions are the groups IIAB and IIG, which have been proposed to sample two immiscible melts from the same core. To test this model, we report the first Fe, Ni, O, and Cr isotope data for IIG iron meteorites and the first high-precision O isotope data for IIAB iron meteorites. The new data demonstrate that IIG iron meteorites belong to the non-carbonaceous (NC) meteorites. This is evident from the isotope anomaly of each of the four elements investigated, where the IIG irons always overlap with the compositions of NC meteorites but are distinct from those of carbonaceous (CC) meteorites. Moreover, among the NC meteorites and in particular, the NC irons, the isotopic composition of the IIG irons overlaps only with that of the IIAB irons. The combined Fe-Ni-O-Cr isotope data for IIAB and IIG iron meteorites, therefore, reveal formation from a single isotopic reservoir, indicating a strong genetic link between the two groups. The indistinguishable isotopic composition of the IIAB and IIG irons, combined with chemical evidence for the formation of IIG irons as late-stage liquids of the IIAB core, strongly suggests that both groups originate from the same core. The results underscore the strength of utilizing multiple elements to establish genetic links among meteorites, rather than using a single element. They also highlight the significance of integrating multiple geochemical tracers and petrologic observations to accurately determine genetic relationships and the formation of meteorites within the same parent body.

We will be back after this years annual meeting of the Meteoritical Society in Brussels.

^1,2,3Candice C. Bedford et al. (>10)
Journal of Geophysical Research (Planets) (in Press) Open Access Link to Article [https://doi.org/10.1029/2023JE008261]
¹Lunar and Planetary Institute, Universities Space Research Association, Houston, TX, USA
²Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX, USA
³Department of Earth, Atmospherics, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
Published by arrangement with John Wiley & Sons

Candidate glaciovolcanic landforms have been identified across Mars, suggesting that volcano-ice interactions may have been relatively widespread in areas that once contained extensive surface and near-surface ice deposits. To better constrain the detection of glaciovolcanism in Mars’ geological record, this study has investigated and characterized the petrology, geochemistry, and mineralogy of three intraglacial volcanoes and an interglacial volcano in the Þórisjökull area of southwest Iceland. Our results show that glaciovolcanism creates abundant, variably altered hyaloclastite and hyalotuff that is sufficiently geochemically and mineralogically distinctive from subaerially erupted lava for identification using instruments available on Mars rovers and landers. Due to the lower gravity and atmospheric pressure at the surface of Mars, hyaloclastite and hyalotuff are also more likely to form in greater abundance in Martian glaciovolcanoes. Our results support that magmatism following deglaciation likely triggers decompression melting of the shallow mantle beneath Iceland, creating systematic changes in geochemistry and mineralogy. Glaciation can also suppress magmatism at its peak, encouraging the formation of shallow fractionated magma chambers. As such, it is possible for the crustal loading of an ice cap to enhance igneous diversity on a planet without plate tectonism, creating glass-rich, altered, and mineralogically diverse deposits such as those discovered in Gale crater by the Curiosity rover. However, as the eroded products of glaciovolcanism are similar to those formed through hydrovolcanism, the presence of a glaciovolcanic landform at the source is required to confirm whether volcano-ice interactions occurred at the sediment source.

¹Yuxuan Luo,¹Jianjun Liu,¹Zhaopeng Chen,¹Yizhong Zhang,¹Xing Wang,¹Xin Ren,³Xiangfeng Liu,³Zhenqiang Zhang,³Weiming Xu,³Rong Shu
Journal of Geophysical Research (Planets) (in Press) Link to Article [https://doi.org/10.1029/2024JE008366]
¹Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences (CAS), Beijing, China
²School of Astronomy and Space Science, University of Chinese Academy of Sciences (UCAS), Beijing, China
³Key Laboratory of Space Active Opto-electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences (CAS), Shanghai, China
Published by arrangement with John Wiley & Sons

Mars Surface Composition Detector (MarSCoDe) is one of the important payloads carried by the Zhurong rover, China’s first Mars exploration mission Tianwen-1. The laser-induced breakdown spectroscopy (LIBS) instrument of MarSCoDe is mainly used to detect major and trace elements on the surface of Mars. The quantitative analysis of alkali trace elements, namely lithium (Li), strontium (Sr), and rubidium (Rb), holds significance in unraveling the geological evolution of the Zhurong landing site. This study focuses on establishing univariate calibration models using MarSCoDe LIBS spectra from 84 samples tested in the ground laboratory. The accuracy of these models, within a few parts per million (ppm), was subsequently validated through the analysis of 12 onboard MarSCoDe Calibration Targets (MCCTs). With these models, Li, Sr, and Rb concentrations in the surface targets during the initial 300 sols (Martian days) traverse were determined. These concentrations ranged from 6 to 18, 106–628, and 22–87 ppm, respectively. Our results suggest that Li, Sr, and Rb are mainly related to the igneous rock components in the rocks and soils at the Zhurong landing site. The major secondary minerals in MarSCoDe scientific targets are likely small amounts of sulfates, which appear to have formed from the acidic weathering of recent surface brine. Clay minerals are likely either absent or very sparse in the scientific targets. The surface igneous materials at the landing site likely have originated from the most recent lava flow during the Amazonian epoch.

¹Yu Yu Phua et al. (>10)
Journal of Geophysical Research (Planets) (in Press) Open Access Link to Article [https://doi.org/10.1029/2023JE008251]
¹Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
Published by arrangement with John Wiley & Sons

The Mars 2020 Perseverance rover has explored fluvio-lacustrine sedimentary rocks within Jezero crater. Prior work showed that igneous crater floor Séítah and Máaz formations have mafic mineralogy with alteration phases that indicate multiple episodes of aqueous alteration. In this work, we extend the analyses of hydration to targets in the Jezero western fan delta, using data from the SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) Raman spectrometer. Spectral features, for example, sulfate and hydration peak positions and shapes, vary within, and across the crater floor and western fan. The proportion of targets with hydration associated with sulfates was approximately equal in the crater floor and the western fan. All hydrated targets in the crater floor and upper fan showed bimodal hydration peaks at ∼3,200 and ∼3,400 cm−1. The sulfate symmetric stretch at ∼1,000 cm−1 coupled with a hydration peak at ∼3,400 cm−1 indicate that MgSO4·nH2O (2 < n ≤ 5) is a likely hydration carrier phase in all units, perhaps paired with low-hydration (n ≤ 1) amorphous Mg-sulfates, indicated by the ∼3,200 cm−1 peak. Low-hydration MgSO4·nH2O (n = 1–2) are more prevalent in the fan, and hydrated targets in the fan front only had one peak at ∼3,400 cm−1. While anhydrite co-occurs with hydrated Mg-sulfates in the crater floor and fan front, hydrated Ca-sulfates are observed instead at the top of the upper fan. Collectively, the data imply aqueous deposition of sediments with formation of salts from high ionic strength fluids and subsequent aridity to preserve the observed hydration states.

^1,2L.Mandon et al. (>10)
Journal of Geophysical Research (Planets) (in Press) Open Access Link to Article [https://doi.org/10.1029/2023JE008254]
¹Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
²University of Grenoble Alpes, CNRS, IPAG, Grenoble, France
Published by arrangement with John Wiley & Sons

Using relative reflectance measurements from the Mastcam-Z and SuperCam instruments on the Mars 2020 Perseverance rover, we assess the variability of Fe mineralogy in Noachian/Hesperian-aged rocks at Jezero crater. The results reveal diverse Fe3+ and Fe2+ minerals. The igneous crater floor, where small amounts of Fe3+-phyllosilicates and poorly crystalline Fe3+-oxyhydroxides have been reported, is spectrally similar to most oxidized basalts observed at Gusev crater. At the base of the western Jezero sedimentary fan, new spectral type points to an Fe-bearing mineral assemblage likely dominated by Fe2+. By contrast, most strata exposed at the fan front show signatures of Fe3+-oxides (mostly fine-grained crystalline hematite), Fe3+-sulfates (potentially copiapites), strong signatures of hydration, and among the strongest signatures of red hematite observed in situ, consistent with materials having experienced vigorous water-rock interactions and/or higher degrees of diagenesis under oxidizing conditions. The fan top strata show hydration but little to no signs of Fe oxidation likely implying that some periods of fan construction occurred either during a reduced atmosphere era or during short-lived aqueous activity of liquid water in contact with an oxidized atmosphere. We also report the discovery of alternating cm-scale bands of red and gray layers correlated with hydration and oxide variability, which has not yet been observed elsewhere on Mars. This could result from syn-depositional fluid chemistry variations, possibly as seasonal processes, or diagenetic overprint of oxidized fluids percolating through strata having variable permeability.