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.

¹Tian Feng,^1,2Arthur Omran,¹Maheen Gull,³Micah J. Schaible,^3,4Thomas M. Orlando,¹Matthew A. Pasek
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2024.07.022]
¹School of Geosciences, University of South Florida, NES 204, 4202 East Fowler Ave., Tampa, FL 33620, USA
²Department of Chemistry, University of North Florida, Jacksonville, FL 32224, USA
³School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
⁴School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
Copyright Elsevier

Phosphorus is often present in meteorites as the mineral schreibersite, in which P is in a reduced oxidation state as a phosphide. Phosphides such as schreibersite have been proposed to be important to the development of life on the earth and may serve as indicators of metamorphic grade on meteorite parent bodies. Here we investigate how synthetic schreibersite (as the iron end-member, Fe3P) oxidizes into calcium phosphates through reaction with silicates under high temperature conditions, at specific oxygen fugacities, and in the absence of water. We find that schreibersite readily oxidizes to phosphates at temperatures of 750–850 °C over a few weeks depending on the oxygen fugacity of the environment. The rate of this process is best matched by diffusion-limited kinetics. Therefore, the metamorphic heating timescale required to equilibrate phosphorus in meteoritic samples with small schreibersite grains (∼1 μm), such as in the type 3 ordinary chondrites (3.0–3.3), was short (10–100 days).

^1,2Aryavart Anand,²Klaus Mezger,^2,3Beda Hofmann
Meteoritics & Planetary Science Open Access Link to Article [https://doi.org/10.1111/maps.14242]
¹Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany
²Institut für Geologie, Universität Bern, Bern, Switzerland
³Naturhistorisches Museum Bern, Bern, Switzerland
Published by arrangement with John Wiley & Sons

Precise measurements of Cr isotopic composition of terrestrial impactites have successfully provided evidence for the presence of extraterrestrial material and have, in some cases, allowed the identification of the type of impactor responsible for the formation of the impact structure. The high Cr abundance in most meteorite groups aids in detecting extraterrestrial contamination while their distinct isotopic compositions can help with the identification of the nature of the projectile. However, this common approach of detection and identification of extraterrestrial contamination using mass-independent 53Cr and 54Cr variations fails when the impactor type is an iron meteorite because of their low Cr abundances (which are in a similar range to terrestrial rocks). The present study demonstrates the viability of a spallogenic Cr contribution in iron meteorites (resulting from their long cosmic ray exposure times), which compensates for their low Cr abundances and facilitates the identification of iron-meteoritic contamination in terrestrial impactites. Thus, it broadens the scope of impactors (and impactites) that can be investigated using mass-independent Cr isotopes from solely chondrites and primitive achondrites to include iron meteorites. The Wabar impact craters are an optimal candidate for this study, characterized by low weathering, diverse impactites, partial meteorite survival, substantial impactor material contamination, and a felsic target lithology with low background Cr concentration. The Cr isotopic composition of the Wabar background sand, which represents the target lithology, is indistinguishable from the terrestrial Cr isotopic composition range, whereas the Wabar iron meteorites show coupled spallogenic excesses in ε53Cr and ε54Cr. The Cr isotopic compositions of Wabar impactites show resolved deviations from the terrestrial Cr isotopic composition, thereby indicating the presence of Wabar meteoritic contamination. Moreover, the study demonstrates that even an impactor with a non-carbonaceous chondritic origin, such as a IIIAB iron meteorite, can have a carbonaceous chondrite-like signature in ε54Cr anomalies due to spallogenic Cr contamination. The study advocates for a comprehensive investigation combining platinum group elements and Cr (and/or Ni, Ru) isotopes to accurately characterize impactor types.

¹Hussein, Hussein Omran,¹Yaseen, Waleed Ibrahim
Iraqi Journal of Science 65, 2925-2933 Open Access Link to Article [DOI 10.24996/ijs.2024.65.5.43]
¹Department of Astronomy, Space -College of Science, University of Baghdad, Baghdad, Iraq

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¹Cantillo, David C.,¹Ridenhour, Kaycee I.,¹Battle, Adam,¹Joyce, Thomas,¹Nunez Breceda, Juliana,²Pearson, Neil,¹Reddy, Vishnu
Planetary Science Journal 5, 138 Open Access Link to Article [DOI 10.3847/PSJ/ad4885]
¹Lunar and Planetary Laboratory, University of Arizona, Tucson, 85721, AZ, United States
²Planetary Science Institute, Tucson, 85719, AZ, United States

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¹Gordon R. Osinski,¹Richard A. F. Grieve
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14241]
¹Department of Earth Sciences, University of Western Ontario, London, Ontario, Canada
Published by arrangement with John Wiley & Sons

One of the most common types of allochthonous impactite produced in hypervelocity impact events is impact breccia that contains melt particles. In numerous terrestrial hypervelocity impact structures such melt-bearing breccias have been termed “suevite,” after the type locality at the Ries impact structure, Germany. Despite its widespread occurrence, the origin, emplacement, and classification of suevite remains debated. In this contribution, we re-examine the nature and origin of suevite at the Ries impact structure. The results of new field and laboratory investigations, when combined and synthesized with results from previous studies, lead to a multi-stage model for the origin and emplacement of allochthonous impactites during the Ries impact event. Following the creation of a transient cavity the so-called Bunte Breccia and “megablocks” were emplaced via ballistic sedimentation and subsequent radial flow during the excavation stage to form a continuous ejecta blanket. At the end of the excavation stage, a mixture of melt and lithic fragments formed a lining to the transient cavity and it is this material that later became the crater, dike, and outer suevite (OS) units. The crater suevite represents the material from the displaced zone of the transient cavity that was transported and mixed but never left the cavity. The emplacement of dike suevite occurred during the modification stage as the crater suevite was intruded into fractures in the underlying crater floor. The OS and rare impact melt rocks overlying the ballistic (Bunte Breccia) ejecta deposits were emplaced as outwards-directed ground-hugging flows largely during the modification stage of crater formation. The OS flows varied both spatially and temporally in terms of the flow characteristics, from being dominated by solid particles and gas (cf. pyroclastic density currents) to a mixture of solid particles, liquid (impact melt), and minor gases (i.e., particulate impact melt-rich flows). These particulate impact melt-rich flows dominated by far. Minor “fallback” of material from an ejecta plume is evidenced by accretionary lapilli in the Nördlingen 1973 core. In summary, allochthonous impactites at the Ries impact structure are not unusual but are consistent with observations from other terrestrial and planetary craters, where melt-rich impactites overly ballistic ejecta deposits both outside and inside crater rims and where melt-rich impactites occur in crater interiors.