The Martian meteorite North-west Africa (NWA) 16254 is classified as a gabbroic shergottite, representing the first documented geochemically depleted member of this textural group. This coarse-grained cumulate comprises pyroxenes (augite and pigeonite), maskelynite, and accessory phases, exhibiting a two-stage crystallization history: 1) early high-pressure formation of Mg-rich pyroxene cores (4.3–9.3 kbar) at the Martian mantle‒crust transition zone, followed by 2) shallow crustal crystallization (< 4 kbar) of Fe-enriched pyroxene rims and plagioclase. Geochemical analyses reveal a depleted shergottite signature characterized by pronounced light rare earth element (LREE) depletion and redox conditions indicative of a reduced mantle source. The oxygen fugacity (fO₂) calculated via pigeonite-core Eu oxybarometry yields IW − 1.0 ± 0.2, corroborated by late-stage Ti³⁺-bearing ilmenite assemblages, which reflect sustained reducing conditions during crystallization.

The bulk-rock major element compositions and Mg# values closely align with the depleted shergottite Queen Alexandra Range (QUE) 94201, suggesting a potential cognate origin from a shared magma system. The gabbroic texture and protracted crystallization history of NWA 16254 provide critical insights into prolonged magma chamber evolution within the Martian crust, implicating episodic melt extraction from a long-lived, incompatible element-depleted mantle reservoir. These findings redefine textural diversity among depleted shergottites and underscore the need for geochronological studies to resolve temporal links between ancient mantle processes and Amazonian magmatism.

Enstatite chondrite meteorites are chemically and isotopically related to the precursors of inner Solar System planetesimals, and bear evidence of shock metamorphism which reflects events in enstatite chondrite evolution. Here, we build upon a micro-X-ray diffraction (micro-XRD)-based method to relate strain-related mosaicity (SRM) to petrographic shock stage. Making use of the peak pressure ranges estimated for the petrographic shock stages, we are able to provide quantitative constraints on the peak shock pressures recorded in enstatite (MgSiO₃). Full-width at half-maximum measurement of X-ray diffraction maxima distributed along the Debye rings (ΣFWHMχ) are a proxy for SRM in enstatite grains. Eleven Antarctic enstatite chondrites spanning all documented shock stages (S1−S5), petrologic types, and metamorphic grades, are used to establish a linear correlation P (GPa) = 4.62 × ΣFWHMχ + 0.57; with R² = 0.92 between estimated peak shock pressure and ΣFWHMχ. Enstatite lattice planes (020), (610) and (131) show similar ΣFWHMχ values where meaningful comparisons can be made, suggesting that enstatite has, within measurement error, an isotropic response to shock deformation along its three crystal axes. The (610) reflection is particularly productive at all shock stages and could be used exclusively for future peak pressure studies, under the assumption that enstatite is isotropic to shock deformation. This 2D XRD method enables the estimation of peak shock pressures up to at least 30 GPa in enstatite chondrites and for other enstatite-rich meteorites.

Jarosite is an important Martian sulfate mineral with the potential to record the physicochemical conditions and fluid evolution of aqueous environments on Mars. Previous studies suggest that jarosite can incorporate trace halogens such as bromide (Br⁻), offering insights into paleo-fluid composition and halogen cycling on early Mars. However, the mechanisms governing halogen incorporation remain poorly constrained. In this study, we systematically examined K- and Na-jarosite synthesized from Br⁻/Cl⁻−bearing solutions prepared via two distinct pathways: Fe²⁺ oxidation at 25 °C and Fe³⁺ hydrolysis at 140 °C. Building on previous studies of low-temperature K-jarosite, we broadened the dataset to include both K- and Na-jarosite synthesized via Fe²⁺ oxidation and Fe³⁺ hydrolysis, and performed integrated chemical, crystallographic, and spectroscopic analyses to assess halogen uptake and substitution mechanisms. Our results show that Br⁻ is preferentially incorporated into K-jarosite, particularly under low-temperature conditions, with solid-liquid partition ratios (C_s-Br/C_aq-Br) exceeding 18. In contrast, Na-jarosite remains halogen-poor and exhibits structurally Fe deficiency across all tested conditions. Collectively, Raman spectroscopy, XRD lattice contraction, and stoichiometric data indicate that Br⁻ and Cl⁻ primarily substitute for structural OH⁻ groups, with maximal substitution in low-temperature K-jarosite. Halogen incorporation is strongly controlled by the A-site cation and synthesis pathways, with K-jarosite accommodating far more halogen than Na-jarosite. Low-temperature conditions may promote Br⁻ uptake via defect trapping and slower crystallization kinetics, whereas hydrothermal synthesis enhances crystallinity but reduces halogen incorporation. The Br⁻ enrichment in jarosite parallels that observed in kainite-type double salts, suggesting that jarosite can act as a selective Br⁻ sink in oxidizing acidic systems. On Mars, Br-bearing jarosite may reflect formation in low-temperature, chemically evolved brines. These findings underscore the dual role of jarosite as both paleoenvironmental proxy and an active participant in halogen cycling. Variations in halogen content, crystallinity, and lattice parameters may provide valuable constraints for reconstructing aqueous histories in future returned Martian samples.

Gadolinium (Gd), as one of the rare earth elements, plays a significant role in planetary science and studies of early solar system evolution, since its isotopic composition can record both fractionation processes within nebulae and preserve primordial nucleosynthetic heterogeneities inherited from presolar materials. Among the isotopes of gadolinium, ¹⁵⁵Gd and ¹⁵⁷Gd have exceptionally high neutron absorption cross-sections, making the separation of these isotopes highly valuable as excellent neutron absorbers. However, with increasing applications, it has become an emerging contaminant in aqueous environments. This study employs quantum chemical software packages Gaussian09 and DIRAC19 to systematically investigate the coordination behavior of four functionalized crown ether resins (abbreviated as PMADB15C5, PMADB18C6, PMADB21C7, and PMADCH18C6) with Gd³⁺ ions, and evaluates their contributions to Gd isotope fractionations caused by both mass-dependent and the nuclear volume effects in terms of ¹⁶⁰Gd/¹⁵⁵Gd and ¹⁶⁰Gd/¹⁵⁷Gd. Our results indicate that in aqueous solutions, functionalized crown ether resins preferentially enrich light Gd isotopes compared to the [Gd(H₂O)₉]³⁺. Among them, PMADB15C5 exhibits the greatest potential for Gd isotope fractionations and is identified as a more reliable adsorbent for gadolinium isotope purification. Using the Rayleigh fractionation model at standard conditions (298.15 K, 1 atm) and taking the ¹⁶⁰Gd/¹⁵⁵Gd pair as an example, the isotopic fractionations induced by the adsorption process can be limited to within 0.138‰ when PMADB15C5 is used as the adsorbent with yield ≥ 95%. This study elucidates, at the molecular level, the coordination mechanisms between functionalized crown ether resins and Gd³⁺ ions. The theoretical findings on isotopic fractionation provide important insights for designing and optimizing chemical procedures in Gd isotope analysis.