Here we report the in situ ion-microprobe analyses of the Li- and O-isotope compositions of enstatite, FeO-rich pyroxene, olivine, glass, and cristobalite grains from six chondrule-related objects from the Sahara 97103 EH3 chondrite. The O-isotope composition of the enstatite grains scattered around the intersection between the terrestrial fractionation and primitive chondrule minerals lines. Whereas

Subduction zones act as pivotal engines for global element cycling. Titanium (Ti) isotopes, exhibiting mass-dependent fractionation, emerge as a robust geochemical tracer for deciphering complex processes in these dynamic settings. However, the behavior of Ti and its isotopes during metamorphic dehydration and partial melting of deeply subducted continental lithosphere remains poorly constrained. This

The genesis and compositional diversity of granites are primarily controlled by multiple processes, including partial melting and magma differentiation. However, discriminating the individual effects of processes such as partial melting, fractional crystallization, and fluid-magma interaction on the evolution of granitic magma remains challenging. Barium isotopes serve as a potentially powerful tracer

Microbial iron and manganese respiration processes have been observed in deep methanic sediments of lacustrine and marine environments, challenging the “classical” model of microbial respiration in aquatic systems. Nonetheless, assessments of the type and relative role of these respiration processes in the methanic zone are lacking. Here, we quantify both the thermodynamic and the kinetic controls

We present electron probe micro analyses (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) mineral chemistry and B-isotope data for magmatic and hydrothermal Li-Fe micas of the granite-related Sn-W-Li Sadisdorf greisen system in the Erzgebirge, Germany. These mineral-specific data were combined with novel in-situ mica and whole-rock powder-pellet LA-ICP multi-collector

Sulfur isotopic values (δ34S) of pyrite and organic matter (OM) in sediments are widely used for the reconstruction of the sulfur and oxygen cycles as well as pathways of OM preservation. Currently, significant uncertainties persist regarding the mechanism by which sulfur is partitioned between pyrite and OM and its effect on the δ34S record of rocks. Here, we present experimental analysis of iron

Studies of shock metamorphic effects in apatite and merrillite in nine ordinary chondrites (OCs) of petrologic types 3.5–6 and shock metamorphic stages S1–S5 using transmission electron microscopy (TEM) reveal a correlation between the extent of brittle deformation in phosphates and the shock metamorphic stage of six host meteorites. No correlation is observed in thermally annealed and partially melted

Pyrite from hydrothermal deposits often exhibits oscillatory zoning, controlling the distribution of trace elements, like As and Au. The origin of this zonal pattern has long been debated between episodic fluid changes and local chemical disequilibrium. Our study of an epithermal Pb-Zn deposit reveals arsenic oscillatory zonation in monocrystalline pyrite grains. Guided by the results of examination

The redox capacities of soil DOM regulate the oxidation–reduction reactions by accepting or donating electrons, which influences a variety of critical redox processes such as greenhouse gas emissions and the (bio)geochemical cycle of contaminants. The composition and reactivity of DOM components vary with their molecular weight (MW), and, therefore, the redox capacities of soil DOM are expected to

Zirconium (Zr) isotopes are an emerging tool to study igneous processes. However, Zr isotope fractionation mechanisms are debated, especially regarding the relative roles of kinetic and equilibrium effects. Here, we report high-precision in-situ Zr isotope (δ94Zr) measurements in zircons from granitoids with ages of 3.4 to 2.5 Ga. The δ94Zr values in all magmatic zircons range from −0.63 to + 0.41 ‰

Ferromanganese concretions in the shelf sea regions, such as the Baltic Sea, are of significant interest due to their geochemical properties, economic resource potential, and roles in benthic ecosystems. This study analyses the authigenic and detrital mineral phases and their provenance in the Baltic Sea concretions, as well as their formation mechanisms and diagenetic evolution. These concretions

Water plays a pivotal role in the differentiation of continental crust and the formation of granitic magmas. However, it is still hotly debated how to identify fluid regimes during crustal anatexis. Molybdenum (Mo) isotopes have shown the potential to trace fluid activity during magmatic and metamorphic processes and thus are a valuable tool to identify the presence of free fluid during crustal anatexis

Magmatism in deep continental arcs is crucial for understanding the formation of andesitic continental crust. Garnet, pyroxene and amphibole are typical major mafic phases in deep arcs, with garnet potentially causing noticeable variations in stable isotopes of major elements such as Ca (δ44/40Ca). The upper continental crust (UCC) shows low δ44/40Ca value (0.70 ± 0.02 ‰, 2SE) relative to oceanic crust

Understanding the structure and transport properties of supercritical fluids is crucial for gaining insights into their behavior in subduction zones. While previous research has provided an understanding of the properties of supercritical fluids derived from felsic melts, our knowledge regarding supercritical fluids formed from ultramafic melts in deep subduction zones remains limited. In this study

Benthic fluxes are critical pathways for constituent exchanges and biogeochemical interactions across sediment–water interface. To comprehensively evaluate the modulation of bioturbation on the benthic fluxes of nutrients, we present a novel inverse geochemical modelling framework in near-surface sediments of Lake Taihu, a highly eutrophic freshwater lake in eastern China. This approach incorporates

Sediments/sedimentary rocks are a major sink of atmospheric N2, which is mainly fixed into diazotrophic biomass and recycled into other organic matters or diagenetically transferred (in the form of NH4+) into the crystal structures of phyllosilicate minerals in sediments. Driven by tectonic activities, sedimentary rocks may experience various degrees of metamorphism with some eventually being melted

The isotopic composition of tooth and bone has long been exploited in ecological, environmental, and archaeological studies. Increasingly, hydrogen and oxygen isotopes in collagen are used as tracers of environment and diet. However, the isotopic relationship between hydrogen and oxygen in collagen and oxygen in tooth enamel is poorly described. A new investigation of varied wild large herbivores shows

The Yangtze River Estuary and the adjacent inner shelf are significant areas for both the burial and degradation of terrestrial organic matter (OM). However, the impact of hydrodynamics on the degradation of different types of organic compound classes has not been fully elucidated. This study measured dual carbon isotopes (δ13C, Δ14C) of organic compound classes [total hydrolysable amino acids (THAAs)

The origin of slab components in arc lavas remains controversial with proposed sources including direct sediment melts, sediment-mantle mélanges, or crustal fluids. Stable isotope distributions of fluid-borne metals and those immobile in subduction components have the potential to trace the respective contribution of these components if placed into the context of additional magmatic differentiation

The Sr and Ca isotope composition, along with trace element content in fossil teeth, provides valuable insights into biogenic and diagenetic processes. Identifying pristine biological signals is crucial for reconstructing the diet and trophic levels of extinct taxa. We present novel geochemical data from Tyrannosauridae and Ceratopsidae teeth of the Late Cretaceous, using radiogenic Sr (87Sr/86Sr)

Constraining mid-ocean ridge magmatic processes is crucial for understanding the geochemical evolution of magmas traversing the oceanic crust. A crucial archive for investigating these magmatic processes is the chemical composition of lower oceanic crust. This study presents Zn isotope data for primitive to highly evolved cumulates from the Mid-Atlantic Ridge (Kane) and the Southwest Indian Ridge (IODP

Coprecipitation of phosphate in calcium carbonate minerals is a ubiquitous geochemical phenomenon in marine sedimentation and cave stalagmite formation, however, it is not clear whether phosphate is incorporated into the calcite structure. In this research, we applied solid-state nuclear magnetic resonance (NMR) spectroscopy to analyze P speciation during coprecipitation with calcite. The 31P NMR results

Ages of angrites, a diverse and rapidly growing group of differentiated meteorites, are important for understanding the history of their parent body, which is proposed to be an archetypal first-generation planetesimal. Angrites also commonly serve as a time reference in the early Solar System chronology. Pb-isotopic ages of angrites can be determined with high precision, and the isotopic composition

The incorporation of trace and minor elements into coral skeletons and the underlying chemical and biological processes that govern them, are highly relevant for understanding coral biomineralization and for accurate reconstructions of past ocean conditions. In the present experimental study, that follows our previous publications (Ram and Erez, 2021, 2023), we determined the partition of six cations

Porewater dissolved organic matter (DOM) in lake sediments is an important contributor to the global carbon cycle. The composition and structures of porewater DOM typically vary with depth, yet the variations in high-resolution depth intervals and the controlling biogeochemical processes are not well understood. Here we performed comprehensive, high-resolution (1 cm interval) characterization of sediment

Thallium (Tl) isotopes are a robust tracer of ancient ocean oxygenation through their link to the burial flux of deep-sea manganese oxide minerals. Yet, the details of Tl geochemistry at the continental margin remain largely unexplored, hindering quantitative application of the palaeoredox proxy. To develop our understanding of Tl diagenesis, phase dynamics, and mass transfer at the continent-ocean

This study investigates hydrogeochemical processes, reaction rates and the effect of spatial scales in mountain carbonate watersheds. A reactive-transport model was deployed to capture the concentration-discharge relations (C-Q relations) of major solute species measured in the river waters of two critical zone observatories located in the south of France (southern Alps and Ardèche). The specific control

Continental flood basalt (CFB) provinces, defined by the rapid emplacement of large volumes of mafic lava, represent some of the most significant large-scale magmatic events in Earth’s geological record. Gaining insight into the origin and evolution of fluid systems within these settings is critical for understanding the geodynamic architecture of large igneous provinces (LIPs) and accompanying mineralisation

Chromitites in ophiolites are recognized for their high concentrations of highly siderophile elements (HSE), notably IPGE (Os, Ir and Ru). However, the effects of this enrichment on ophiolitic rocks and mantle heterogeneity remain poorly understood and to address this issue, we investigated chromitites from the Pozantı-Karsantı and Kızıldağ ophiolites in Türkiye. The results reveal HSE enrichment,

The high-latitude oceans are regions of high mercury (Hg) bioaccumulation, especially in the form of methylmercury (MeHg), which is of great concern in terms of human and ecosystem health. In the high-latitude North Atlantic (60-80°N), the deep water entrains the Hg-enriched Arctic water southwards, consequently influencing global Hg cycling. Whilst Hg removal has been proposed en route from the Arctic

Dissolved organic matter (DOM)-modified organic and inorganic colloids are known to enhance the mobilization and transport of different trace elements in aquatic environments. Occurrences of selenium (Se) in natural waters often positively correlate with DOM under diverse environmental conditions, suggesting that DOM may enhance Se mobilization at the soil/sediment–water interface. Despite its importance

Potassium (K) isotope compositions (δ41K) in global loess deposits can provide valuable insights into the average upper continental crust (UCC). However, current knowledge of δ41K in the UCC is limited due to the lithological complexity of the continental crust, which results in highly variable K isotope compositions. Accurately estimating the K isotope composition of the UCC remains a challenge. Here

Apatites and amphiboles are common hydrous minerals in igneous and metamorphic rocks, which can be found from the crust to the lithospheric mantle. These minerals can incorporate chlorine (Cl) and fluorine (F) by substituting for hydroxyl groups (OH). The isotopic compositions of Cl, Ca, and O of apatites and amphiboles are valuable geochemical tools for understanding the terrestrial and extraterrestrial

In addition to copper, gold, and molybdenum, porphyry deposits are important reservoirs of critical metals such as rhenium, selenium, tellurium, and platinum group elements (PGEs). However, enrichment of cobalt (Co) has received little attention. Several studies have shown that Co enrichment does occur in porphyry deposits, however, the source(s) of Co and the mechanism(s) responsible for its enrichment

Previous studies of natural samples have documented marked variations in zircon Zr stable isotopes. However, the petrological mechanisms responsible for Zr stable isotopic fractionation during magmatic differentiation remain unclear. To address this, in situ Zr stable isotopic analyses of magmatic zircons were carried out on a suite of mafic plutonic rocks from the southwestern Tianshan, west China

The survivability and pathways of amino acids in oceanic hydrothermal systems can be affected by fluid chemistry and composition including the presence of inorganic materials, however, their specific effects and underlying mechanisms remain largely unexplored. Using phenylalanine as a model compound, we find that decarboxylation is the primary degradation pathway for amino acids followed by deamination

The occurrence of hydroxylated minerals in carbonaceous chondrites provides valuable insights of water –rocks interactions in hydrous asteroids. Yet, the evolution of water-organic-rock type experiments, applied to carbonaceous chondrites, remains understudied. Here, we present experimental studies of chondritic analogs containing a mixture of minerals and 4 wt% of OM under hydrothermal anoxic conditions

Fluids or melts liberated from subducting slabs promote metasomatism of the overlying mantle wedge, enriching it in volatiles, such as sulfur and carbon, and possibly ore-forming chalcophile metals. Despite the genetic links, the redox evolution of arc mantle, mineralization at convergent margins, the S species in slab fluids and related metal transfer remain poorly understood, also because physicochemical

Coastal Antarctica is experiencing rapid environmental change with potential effects on regional marine trace element biogeochemistry. Here, we investigate the biogeochemistry of two dissolved bioactive trace elements, zinc (Zn) and cadmium (Cd), and their isotope ratios (δ66Zn and δ114Cd) in two coastal marginal seas with distinct oceanographic features – the Amundsen Sea with the intrusion of Circumpolar

The Peruvian margin is one of the biologically most productive regions in the world ocean. The oxygen minimum zone impinges on the seabed over the outer continental shelf and across the upper slope to about 700 m water depth. Due to the partial or complete anoxia, microbial sulfate reduction is a predominant, terminal pathway of organic matter oxidation in the sediment. Sulfate reduction rates (SRR)

Understanding chondrule formation processes has been a major focus of the cosmochemistry community for many decades. In order to help further this understanding, here we apply high-precision K isotope analyses to chondrule fractions from the four Antarctic unequilibrated ordinary chondrites of QUE 97008 (L3.05), MET 00452 (L(LL)3.05), GRO 95658 (LL3.3), and GRO 95539 (LL3.2). The K isotope ratios of

Proxy-based reconstructions of past changes in atmospheric carbon dioxide concentrations (pCO2) are essential for understanding climate dynamics. A common method for reconstructing past pCO2 is based on the carbon isotopic fractionation during photosynthesis by Rubisco (εp). This proxy method is based upon the difference (εp) between the stable carbon isotopic composition (δ13C) of dissolved CO2 and

A series of detailed, systematic experiments were conducted to determine hydrogen and triple-oxygen isotope effects of water adsorption on KGa-2 kaolinite from the Clay Mineral Society at 30 °C as a function of the relative vapor pressure (p/po). Both hydrogen and oxygen isotope fractionation factors between the adsorbed water and water vapor are smaller than those of the liquid water – water vapor

The traditional model that attributes the genesis of basaltic arc magma to the partial melting of metasomatized mantle wedges is increasingly being challenged by evidence highlighting the critical role of dehydrated oceanic crust. Molybdenum (Mo) isotopes (expressed as δ98/95Mo, relative to the NIST SRM 3134 standard) from subarc mantle-derived mafic cumulate rocks offer a novel perspective on this

Erg Cech 002 (EC 002) is an andesitic achondrite, the earliest formed achondrite identified to date, and is a rare sample of primary melts that formed crusts on the first generation(s) of planetesimals. Given that EC 002 represents a primary or primitive melt and that H and F are incompatible during silicate partial melting, EC 002 may be a H- and F-rich material relative to previously studied achondrites

The phyllosilicate clay mineral kaolinite can preserve paleoclimate information on the hydrogen and oxygen stable isotope composition of the water the mineral formed from, as well as its formation temperature. Oxygen in kaolinite exists in three distinct bonded groups: Si-O-Si, Si-O-Al, and Al-OH; and it has been an outstanding analytical problem to feasibly and accurately measure the oxygen isotope

We present the first stable chromium isotope dataset for a suite of island arc basalts (IABs) from Kamchatka to investigate chromium isotope fractionation during magmatic processes in a subduction setting. The chromium isotopic data (δ53Cr) for Kamchatka arc magmas range from –0.09 ± 0.02 ‰ to –0.16 ± 0.02 ‰ (2σ, n = 22). These magmatic rocks exhibit a positive correlation between MgO content and Ni

Enstatite meteorites, including enstatite chondrites and enstatite achondrites (e.g., aubrites), formed under highly reducing conditions in the solar system. Enstatite chondrites underwent progressive thermal metamorphism from petrologic type 3 to type 6, potentially leading to vaporization and redistribution of volatile elements. Coupled Rb and K isotopic analyses of enstatite meteorites could provide

Hyper-velocity impacts are dominant agents in the physical and chemical alteration of lunar surface materials. Natural small-scale craters on lunar soils provide an opportunity to understand the impact process and specific space weathering effects on minerals, however, they have not been systematically studied. Here, we report the morphology and microstructure of submicron-scale craters on Chang’e-5

Microaerophilic and phototrophic iron-oxidizing bacteria (FeOB) deal with the threat of cell encrustation by developing effective survival strategies, such as the production of extracellular organic structures for preferential nucleation. However, nitrate-reducing iron-oxidizing (NRFO) bacteria are not reported to have similar survival strategies. In this context, goethite and magnetite were chosen

The triple oxygen isotope composition of biominerals is a promising recorder of changes in global primary productivity (GPP), as well as environment and animal physiology. However, application is largely unexplored, particularly in many regions of the world where eggshell is a common component of paleontological/archeological sites of the late Cenozoic. Ratites (ostriches and their relatives), as nonobligate

Magnetotactic bacteria (MTB) possess the ability to precipitate intracellular nanosized magnetite. Their emergence may date back to the early Archean (e.g. 3 Ga) but evidence of such a long history has yet to be provided. MTB identification in the rock record relies on magnetofossils, the residual magnetite crystals that may survive in time to rock deformation and low-grade metamorphism. Several criteria

Serpentinized mantle rocks typically experience multiple alteration events, but to date, identifying distinct serpentinization episodes remains difficult because whole rock geochemical and isotopic analyses reflect the cumulative sum of fluid-rock interactions. Here we unravel the alteration history of serpentinized mantle rocks by undertaking multi-stage progressive leaching experiments to isolate

Trace elements in sulfides are commonly used to determine the physicochemical conditions of ore deposit formation. The thermodynamic models underpinning these studies rely on the assumption that trace elements are incorporated into the mineral’s crystal structure, however recent atomic-scale investigations suggest that this assumption may be erroneous, especially in metamorphosed environments. Here

Unconformity-related uranium deposits (URU deposits) in the Proterozoic Athabasca Basin (Canada) represent the largest and richest (with average grades ranging from 0.127 to 19.5 wt% U) U deposits in the world. Fluid inclusion studies and experimental data suggest that the ore-forming fluids of URU deposits are hyperacidic (pH < 3.5), oxidizing basinal brines carrying high concentrations of U (0.2

Stable lithium isotopes (δ7Li) of CaCO3 minerals have increasingly been used as a tracer for changes in silicate weathering processes. However, there is limited understanding of the influence of physical and chemical conditions on δ7Li values of CaCO3 minerals during their formation in aqueous solutions. Here, we examined Li isotope fractionation in inorganic calcite and aragonite precipitation experiments

Foliated calc-silicate schists and quartzites from a ca. 3.71 Ga domain within the northeastern part of the Isua Supracrustal Belt (southern West Greenland) may be interpreted as either deformed layered “metasedimentary” rocks, or the metasomatic fluid alteration products of a deformed mafic igneous precursor (i.e., basaltic protolith). One important reason for protolith assignment in this case stems

Our recent investigations have discovered inward diffusion (in-gassing) of moderately volatile elements (MVEs; e.g., Na, K and Cu) from volcanic gas into volcanic beads/droplets. In this work, we examine the distribution of sulfur in lunar orange glass beads. Our analyses reveal that sulfur exhibits a non-uniform distribution across the beads, forming “U” or “W” shaped profiles typical of in-gassing

Tellurides are abundant in a large variety of hydrothermal Au deposits. Previous studies have proposed that these phases crystallize from polymetallic Te-rich melts that may act as scavengers for Au to form high grade deposits. However, the conditions under which Te-rich melts form and whether such melts can act as agents to concentrate Au have not been directly assessed. Here, we present an experimental

The Mo stable isotope system is a promising tracer of crustal recycling. As subduction zones play a major role in returning crustal material back to the Earth’s mantle, understanding the Mo isotope behavior during processes operating at these settings is paramount. The Mo isotope compositions of arc lavas are highly variable and despite recent advances in this field, questions remain about Mo isotope