Calcium-aluminum rich inclusions (CAIs) are the oldest condensates in the Solar System. Previous studies have revealed that moderately heavy and trace element isotope anomalies (e.g., Ti, Sr, Mo, and Nd) in CAIs record large nucleosynthetic isotope variations compared to bulk meteorites. Calcium is a major element in CAIs that has six stable isotopes with multiple nucleosynthetic origins. As such,

The formation of a unique microstructure of minerals on the surface of airless bodies is attributed to space weathering. However, it is difficult to distinguish the contributions of meteorite impacts and solar wind to the modification of lunar soil, resulting in limited research on the space weathering mechanism of airless bodies. The thermochemical reactivity of troilite can be used to distinguish

A remnant of glacial seawater preserved in the pore fluids of sediment cores from the Maldives Inner Sea provided an opportunity to investigate the stable strontium isotopic composition (δ88/86Sr) of the ocean during the Last Glacial Maximum and explore the usefulness of δ88/86Sr as a tracer of early marine diagenesis. We used paired measurements of δ88/86Sr and radiogenic Sr isotope ratios (87Sr/86Sr)

The formation of polymers that can hold gene information and work as catalysts is a crucial step for the origin of life. The discovery of catalytic RNA (i.e., ribozyme) supports the hypothesis that RNA might have served these functions at the early stage of life on the Earth. Given this, the spontaneous formation of RNA monomers (i.e., ribonucleotides) and their polymerization on Hadean Earth are essential

The δ30Si and δ18O values of opal-A precipitated in plants (silica phytoliths) have been shown to be useful for paleoenvironmental reconstructions. Here, the effects of burning and partial dissolution of phytoliths on their isotopic compositions and dissolution behaviour were examined. Phytoliths were heated to 700 °C and then dissolution experiments were conducted in batch reactors under a range of

Cadmium (Cd)-bearing sphalerite (SP, ZnS) and smithsonite (SM, ZnCO3) particulate matter (PM) is deposited on soils near carbonate-hosted Zn ore deposits. Whether and how carbonate rocks such as limestone influence the mobility of Cd and Zn in soils is largely unknown. For this reason, we conducted a soil incubation experiment to investigate the chemical and mineralogical changes in soil–soil solution

Understanding of the diversity and petrogenesis of achondrites is critical for deciphering magmatic processes and the early evolution of planets and asteroids. Here, we report the detailed petrologic, mineralogical, geochemical, and chronological features of the unbrecciated Vestan meteorite Northwest Africa (NWA) 8326. We found that NWA 8326 is composed of coarse-grained orthopyroxene (∼74 vol%),

Water significantly impacts the chemical evolution of the Earth’s crust, affecting environments from volcanic settings to hydrothermal systems. These fluids transport elements essential for geological processes, such as metal ore deposit formation. At high temperatures, as water transitions from liquid to vapor, its molecular structure changes, drastically reducing its capacity to dissolve solids and

Tropical small mountainous rivers (SMRs), characterized by extensive basin weathering, discharge high amounts of sediments and particulate terrestrial organic carbon (OCterr) into the ocean. Burial of OCterr in marine sediments is important for atmospheric CO2 sequestration, yet its rate and efficiency remain not fully understood. Previous studies indicated generally low burial rates and burial efficiencies

Fifteen elements, including most of the major elements, were quantified using neutron-induced prompt gamma-ray analysis for five Antarctic carbonaceous chondrites with CI affinities and seven with CM affinities. Common among the twelve meteorites is the depletion of volatile elements H and chlorine, showing a positive correlation and being depleted compared to non-Antarctic CI levels. This depletion

Beryllium isotopes (stable 9Be and cosmogenic meteoric 10Be) enter the oceans through distinct pathways – i.e., from the continents and the atmosphere respectively – and display non-conservative behaviour in seawater. This isotope system has served as a powerful tool for quantifying a variety of processes, including geomagnetism, sedimentation, continental input, and ocean circulation. However, processes

Silica solubility and molecular speciation in hydrothermal water vapor have been determined through quartz solubility experiments at 400–800 °C and 50–270 bar using a novel U-tube flow-through reactor system and theoretical calculations. The results demonstrate that silica concentrations are low in water vapor (mSi,tot = 0.11–4.56 mmol/kg or xSi,tot = 8.21 × 10−5–1.98 × 10−6 mol/mol) increase with

Polycrystalline diamond aggregates (PDAs) are small rocks composed mostly of diamond grains, but often containing also peridotitic, eclogitic and/or websteritic minerals as accessory phases. PDAs are formed rapidly in Earth’s mantle, and the diamonds preserve heterogeneity not often seen in monocrystalline diamond. Here, diamond grains from forty-three PDAs from the Venetia diamond mine (RSA) with

Knowledge of the partial molar volumes of aqueous ions allows accurate calculation of the pressure dependence of equilibrium constants, solubility of minerals, etc., thus being useful for thermodynamic modeling of hydrothermal processes. This study analyzed methods to correlate and predict the values of the partial molar volumes at infinite dilution, V2o, for 1–1 electrolytes and singly charged ions

Anomalously high metal concentrations including iron enrichments are recorded in marine carbonates deposited during Ocean Anoxic Event 2 (OAE 2). These metal enrichments have been attributed to massive submarine eruptions during the formation of one or more large igneous provinces, the proposed trigger for OAE 2 (hydrothermal hypothesis), or to the release of metals from the reoxidation of formerly

Understanding the behaviour of tantalum (Ta) in hydrothermal systems is pivotal for understanding its geochemical enrichment processes and economic extraction via hydrometallurgy. Yet, its behaviour in hydrothermal systems remains poorly characterised. This study investigates the coordination chemistry, speciation, and solubility of pentavalent Ta(V) in fluoride (F) − and chloride (Cl) −rich hydrothermal

The relationship between microbial activity and the supergene modification of ore systems has been a major subject of debate. Here, we present isotopic evidence of microbial-driven secondary copper mineralization in the active cementation zone of the Las Cruces deposit, a volcanogenic massive sulfide deposit located in Iberian Pyrite Belt, Spain. Copper isotopic data show that the lower isotopic ratios

Wildfires impact a large and increasing proportion of the Earth’s surface. With documented soil surface temperatures of up to ∼850 °C, wildfires may fundamentally alter the mineralogy and geochemistry of soils and regolith, more conventionally thought to be dominated by low temperature weathering processes. Here we use an experimental approach to test the effect of temperature on the formation of pyrogenic

Volcanic products returned from the Apollo missions over 50 years ago provide a unique perspective into the magmatic evolution of the Moon. However, questionsremain regarding the volatile loss, crystallization, and emplacement histories of lunar lavas. To address gaps in our understanding of the eruptive histories of lunar lavas, we investigate phase chemistry and 3D morphologies of low-titanium Apollo

Over the last decades, the chromium (Cr) stable isotope system (referred to as δ53Cr) has emerged as a proxy to reconstruct past oxygenation changes in Earth’s atmosphere and oceans. Although Cr is a promising paleoproxy, uncertainties remain as to the modern marine Cr cycle, and limited data are yet available in large swaths of the ocean, including the Atlantic Ocean. Here we present dissolved seawater

The molybdenum (Mo) isotope composition (defined as δ98Mo measured per mil relative to NIST-3134) of many modern arc systems and the upper continental crust is heavier than the mantle and most subducting slab lithologies. This observation has led to a model whereby fluids leaving the slab transfer isotopically heavy Mo preferentially to the mantle wedge, leaving the residual slab isotopically lighter

Ti- and Ba-rich tri-octahedral micas occur in fractionated basic igneous rocks, metasomatized mantle peridotites, metamorphosed pelites/carbonates, and hydrothermally altered mineral deposits. Electron microprobe analyses (EMP), with all iron reported as FeO, were widely used in the 1970/80s to interpret Ti and Ba substitution mechanisms, based on 22 O2– unit cell calculations, implying that cation

Anoxic marine sediments represent an important source of bioavailable iron (Fe) to the ocean. The highest sedimentary Fe fluxes are observed in open-marine oxygen minimum zones where anoxic bottom waters are in contact with ferruginous surface sediments. Here, sedimentary Fe release, transport and re-deposition (i.e., Fe shuttling) may generate a lateral pattern of sedimentary Fe enrichment and depletion

Geothermal waters typically have elevated arsenic (As) concentrations. Various As species have been identified, including methylated thioarsenates, which present a high environmental and health risk due to high mobility and toxicity. Upon discharge from hot springs, temperature and geogenic sulfide excess decrease, while redox potential increases. The combined effects of those parameters on activities

A linear relationship between the logarithms of solute dissociation constants, log(K), and the density of water, log (ρH2O), has empirically been demonstrated for decades and raised hope for an universal formalism to describe solute thermodynamic properties over wide ranges of temperature and density at supercritical conditions. Yet, neither a theoretical foundation nor an assessment of the ranges

The improving sensitivity of mass-spectrometers has opened the potential of using stable isotope signatures of the rare Earth elements (REE) as geochemical tracers. However, thus far only limited studies have utilised REE stable isotopes, despite resolvable variations having been observed in a range of systems. An interesting but poorly explored area remains variations in aqueous environments across

The abundance and oxidation states (II, III and IV) of manganese (Mn) in a weathering profile encompassing both the soil layers (A and B horizons) and the underlaid saprolite (C horizons) determine the availability of Mn as a plant nutrient and regulate its role in cycles of other elements in Earth’s critical zone. However, it remains unclear how the abundance and oxidation states vary with depth under

The marine carbon cycle has a central role in biogeochemical cycling and a close interaction with the climate system. Here, we use the stable carbon isotope (δ13C) of particulate inorganic carbon (PIC) and particulate organic carbon (POC) in marine particles to diagnose carbonate dissolution and organic matter respiration processes in the ocean water column. We show PIC dissolution both in the euphotic

Nitrogen, because of its abundance and variety of carrier phases, is a unique tracer of physico-chemical processes occurring throughout star and planet formations. The refractory organic matter is commonly considered as the main carrier of nitrogen in the most primitive objects of our Solar System. However, nitrogen in the form of ammonium (NH4+) was observed in the Ivuna-type carbonaceous (CI) chondrites

Metamorphic fluids in subduction zones carry C–H–N–O–P–S species, which are crucial for sustaining subsurface microbial life at shallower crustal depths in the forearc region. Upwards migration of deeply released fluids to shallower levels, where temperatures permit the persistence of microbial life, is recorded by metasomatic rocks formed along the plate interface. Variations in the redox state and

The water column distributions of the alkaline earth metals strontium (Sr) and barium (Ba) were studied along a transect from Hawaii to Alaska. Despite similarity in the chemical properties of Sr and Ba, we find that changes in their concentrations along the transect are governed by different chemical and biological processes, meaning that these elements can be treated as independent variables in modern

Mantle-derived mafic rocks show relatively large variations in nickel (Ni) isotopes and mostly isotopically light compared to the bulk silicate Earth (BSE). Whether this signature is due to the source heterogeneity or controlled by melting processes has been a debatable issue. Here, we analyzed Ni isotopic compositions of 18 intraplate basalts from the Sabzevar region, northern Iran and 16 serpentinized

Carbonaceous chondrites contain amino acids, with variable abundances and isotope compositions between and within carbonaceous chondrites. The parent body processes, and the presence of clay minerals may explain those differences. Here, we experimentally investigate the evolution of 6 amino acids (glycine, β-alanine, α-alanine, 2-aminoisobutyric acid, γ-aminobutyric acid, and isovaline) exposed to

Mantle xenoliths provide effective records of the metasomatic processes that affect continental lithosphere evolution, such as interaction with subducted components or modification via small-degree melts. Correlations between major/trace element geochemistry with stable and radiogenic isotope compositions can help constrain the source and timing of this metasomatism. We report new δ18O, δ44/40Ca, and

The formation of nanominerals and mineral nanoparticles (NMMNs) has drawn broad attention due to their high reactivity and omnipresence in the environment. While the heterogeneous formation of NMMNs on surfaces of various minerals has been extensively studied, there is limited understanding of how mineral heteroaggregates influence this process. In this study, we investigated how heteroaggregates of

We present one year of δD, δ18O, d-excess, and Δʹ17O data from monthly precipitation at a Caribbean coastal site in Panama and from tap waters across the country to constrain geographic, climate, and moisture source controls on isotopic variability and better understand the sources and mechanisms of precipitation in Central America, a region facing significant modifications to the annual rainfall cycle

The stable hydrogen isotope composition of archaeal lipids is emerging as a potential paleoenvironmental proxy, adding to the well-established application of plant leaf wax-derived n-alkanes in paleohydrological reconstruction. A handful of studies reported relatively invariant and depleted hydrogen isotope compositions for archaeal lipids despite the range of different organisms and growth conditions

Retention of the pristine hydrogen isotope composition (expressed as δD) formed during mineral formation in equilibrium with water is the basis for any paleoenvironmental reconstructions and for tracing mineral reactions using hydrogen (or H and O) isotope composition in kaolinite. Not only do post-formation reactions cause partial equilibration with ambient water, altering the pristine signature,

Deep-sea mud shows tremendous resource potential for rare earth elements (REEs) and its formation is closely associated with sea-floor hydrothermal activities. Iron (oxyhydr)oxides link the sources and sinks of REEs in sea-floor hydrothermal systems. However, the complexation mechanisms of REEs on iron (oxyhydr)oxides have not been well understood yet. In this study, by using the first principles molecular

Sorption of antimony (Sb) onto birnessite significantly influences the fate of Sb in oceanic and terrestrial environments and fractionates Sb isotopes. Nevertheless, little is known about Sb isotopic fractionation during its adsorption on birnessite. Here, we show the value of Δ123Sbadsorbed-aqueous increases from −0.398 to −0.332 ‰ in 1 h and then decreases and stabilizes at −0.384 ‰ in 72 h. The

Organic carbon burial in ancient lacustrine settings is a crucial source of petroleum resources. Unlike the marine environment, the dynamics of organic carbon burial in the terrestrial realm are more complex due to the interplay of global and regional climate-tectonic factors. There appears to be a potential linkage between seawater incursion events (SWIEs) and the generation of lacustrine source rocks

The solubility of anhydrite in deionized water has been determined experimentally from 380 ˚C to 625 ˚C and 220 bar to 270 bar. The experiments were performed using a unique flow-through reactor capable of reaching supercritical conditions for pure water. The results cover the approximate range of temperature and pressure expected to be found in deep geothermal systems where supercritical conditions

The ∼ 1.15-billion-year-old (Ga) Premier kimberlite pipe (Cullinan diamond mine), South Africa, is composed of several distinct kimberlite facies (Grey, Brown, Pale Piebald, Dark Piebald, Black Coherent [Type 3C], Blue/Brown Transitional, and Fawn). We report bulk rock Re-Os isotope data for Premier kimberlite facies, as well as for a suite of entrained peridotite and mafic xenoliths. These data are

The oceanic chromium (Cr) cycle is mainly governed by the interconversion and the distribution of Cr(VI) and Cr(III) species and their stable isotopic ratios (δ53Cr) in the water column. As a result, the Cr cycle generates a strong correlation between the natural logarithm of its dissolved concentration and δ53Cr regardless of the location of sampling. A few studies have reported the Cr composition

Stable isotopes of metals, such as magnesium (Mg) and iron (Fe), typically undergo minimal fractionation at magmatic temperatures. However, in Fe-Ti oxide-bearing intrusions, significant Mg isotope fractionation (Δ26Mg values of up to 23 ‰) has been observed between silicates and Fe-Ti oxides. The mechanism responsible for this substantial fractionation remains unclear. This study presents Mg isotopic

Rotationally resonant Deuterium Nuclear Magnetic Resonance spectroscopy (D MAS NMR) was applied to IOM isolated from a CR1 chondrite Grosvenor Mountains (GRO) 95577 and a CM2 chondrite (Murchison). It is shown that in IOM D strongly prefers the aliphatic hydrogen reservoir over the aromatic hydrogen reservoir. For GRO 95577, that has a bulk δD of 3303 ‰ (Alexander et al., 2010), the average δD value

Marine dissolved organic matter (DOM) is one of the largest reservoirs of organic carbon and nitrogen in the world. Yet, despite its global importance, most DOM remains molecularly uncharacterized. Solid-state nuclear magnetic resonance (NMR) spectroscopy of isolated DOM fractions represents one of the most powerful techniques to understand overall structural composition. However, it is well known

Tektites are reduced (Fe2+) glasses formed by the quenching of molten material ejected from Earth’s surface as a result of a hypervelocity impact. The vast majority of tektites are usually homogeneous glasses, but rare samples containing mineral inclusions can provide insights about the source material, sample thermal history, and tektite formation process. Tektites from two distinct strewn fields

The Urucum iron- and manganese formation (IF-MnF) in the Santa Cruz Formation, Brazil, was deposited in a glacially influenced, late Neoproterozoic depositional environment. It has proven to be a reliable and robust archive for the late Neoproterozoic, allowing unique insights into the composition of seawater during an interval that is characterized by dramatic changes in the Earth’s litho-, hydros-

Autochthonous dissolved organic matter (Auto-DOM) produced by a biological carbon pump using dissolved inorganic carbon (DIC) from carbonate weathering plays an important role in carbon cycling within inland waters. However, little is known regarding how environmental conditions impact the composition and fate of organic matter, especially in surface waters of the semi-arid Loess Plateau, which is

Magnetotactic bacteria (MTB) produce intracellular magnetite (Fe3O4) nanoparticles in a genetically controlled manner. They may represent some of the oldest biomineralizing organisms available in the geological record, but identification of their fossils remains highly debated. While organic molecules are degraded during diagenesis and metamorphic processes, MTB magnetite nanocrystals can be efficiently

Pressure solution is inferred to be a significant contributor to sediment compaction and lithification, especially in carbonate sediments. For a sediment deforming primarily by pressure solution, the compaction rate should be directly related to the rate of calcite dissolution, transport along grain contacts, and calcite reprecipitation. Previous experimental work has shown that there is evidence that

Increased water temperature and ocean acidification, due to climate change, is predicted to impact aquatic species’ growth, physiology and calcification rates. The present study investigated how a high-emissions scenario of future water temperature and ocean acidification could influence somatic and otolithic growth, and oxygen isotope fractionation in accreted otolith material, of an important fisheries

It is estimated that at least 25 % of the anthropogenic carbon dioxide (CO2) emitted to the atmosphere since the start of the industrial revolution has been absorbed and dissolved by the oceans. The uptake of CO2 by the oceans leads to an increase in the seawater proton concentration ([H+]), and decreases in seawater pH, carbonate ion concentration ([CO32–]), and saturation state (Ω) with respect to