The physical and chemical behavior of carbonate minerals during subduction is key to understanding the carbon cycle process in the deep Earth. Using diamond anvil cells combined with in situ Raman spectroscopy, we investigated talc stability at 200–550 ℃ and 0.5–3 GPa, corresponding to subduction zone conditions. Results demonstrate that talc readily reacts with C-O–H fluid to form magnesite at T >

Dissolved inorganic nitrogen (DIN) is one of the key major nutrients crucial for regulating marine productivity. Photosynthetic endosymbiosis, as seen in organisms like stony corals and foraminifera, appear to alleviate nutrient limitations in surface ocean waters through its symbiotic relationship with the host. Recent advancements in understanding the nitrogen isotopic compositions (15N/14N) of planktonic

Natural organic matter (NOM) serves a crucial electron reservoir for the reduction of hexavalent chromium (Cr(VI)) in subsurface environments. However, the influence of mineral adsorption on Cr(VI) reduction by NOM remains poorly understood, despite the widespread interaction among NOM, mineral matrices and Cr(VI) in natural environments. In this study, aluminum oxides (Al2O3) and Fe oxyhydroxides

Focused melt flow is a common phenomenon in the subcontinental lithospheric mantle. Although it exerts significant control on the magmatic differentiation of the upper mantle, its role in metal transport remains poorly constrained. To improve our understanding of the subcontinental mantle metallogeny, we investigated the Balmuccia massif of the Ivrea-Verbano Zone (Italian Alps), which consists of fresh

Barium (Ba) is a nutrient-type element in the ocean and is commonly used as a tracer for reconstructing marine productivity. Despite recent developments in Ba stable isotope analysis and growing research interest, the controls on biological Ba uptake and isotope fractionation remain largely unknown. This study presents a series of culture experiments using the model marine diatom Thalassiosira weissflogii

Subalpine meadow soil carbon (C) is susceptible to ultraviolet B (UV-B) radiation, yet the mechanisms of UVB-induced soil organic C (SOC) photodegradation and the influence of iron (Fe) on this susceptibility remain largely unknown. In this study, soils from the southeastern (SE) and northwestern (NW) slopes of a subalpine meadow were exposed to three UVB treatments, elevated (ele-UVB, ∼120 μW·cm−2)

Recent studies on alkali metals, Ar-, Fe- and K-isotope distribution in Australasian microtektites have revealed the complex interplay of multiple fractionation processes in establishing their moderately volatile elements record, particularly in those deposited in Antarctica, most distal from the hypothetical source crater. To provide a better understanding of moderately volatile elements fractionation

Microenvironments inside marine organic particles can host anaerobic microbial respiration outside of ocean anoxic zones, but these environments are challenging to directly observe. We present evidence that the planktic foraminifer Globorotaloides hexagonus inhabits a particle microenvironment and suggest that their shell chemistry records anaerobic microbial metabolisms inside particles. We propose

Geothermal systems are hot spots for interaction among minerals, microorganisms, and hydrocarbons. Coupled hydrocarbon transformation and redox cycling of iron in minerals is important to ecosystem functions but remains poorly understood. This work studied abiotic transformation of petroleum hydrocarbons by reactive oxygen species produced upon oxygenation of a reduced clay mineral (nontronite NAu-2)

Particulate (POC) and dissolved organic carbon (DOC) concentration, clay mineral content and composition and the suspended particulate matter (SPM) concentration have been analyzed in water samples taken along transects from the high turbid nearshore to the low turbid offshore on the North Sea shelf. The suspended POC has been classified into a mineral-associated (POCmineral), a slowly degrading (POCslow)

Iceland is a location of geological interest due to the combination of upwelling mantle plume and divergent plate boundary, which resulted in the formation of its extensive surface area (>100,000 km2) that rises above sea-level. This unique setting facilitates assessing the role of the underlying mantle plume and tectonic activity on crust-forming processes. Helium isotopes provide a useful tool in

To better constrain the Ca isotope effect during partial melting of Earth’s mantle, we used ab initio molecular dynamic simulations to calculate the equilibrium mineral-silicate melt Ca isotope fractionation factors for the major Ca-bearing minerals of the upper mantle (orthopyroxene, clinopyroxene, olivine, and garnet), as well as plagioclase. We found that mineral-melt Ca isotope fractionation factors

Nitrogen is important in planetary evolution because it is essential to life and the most abundant element in Earth’s atmosphere. Here, we investigate how core formation affects the distribution of N within accreting terrestrial planets. We conducted laser-heated diamond anvil cell experiments (LH-DAC) over a wide range of high pressure–temperature-compositional (PTX) conditions (38–103 GPa, 2728–5609 K

Knowledge of Fe-Mg interdiffusion coefficients (DFe-Mg) in orthopyroxene (opx) is relevant for diffusion chronometry as well as for thermometers based on Fe-Mg exchange between opx and other common mafic minerals. We extended the existing data set for DFe-Mg to quantify the effect of the molar fraction of Fe, XFe = Fe/(Fe + Mg) = 0.1 to 0.4, and oxygen fugacity, fO2 = 10-7 to 10-11 Pa, in the temperature

Plant leaf waxes and their isotopic composition are important tracers of ecological, environmental, and climate variability, with strong preservation potential in sedimentary archives. However, they represent an integrated, and often complicated, signal of vegetation and hydrology within a watershed. Here, we report a new approach for examining complex mixtures of n-alkanes in sediments and their isotope

This study evaluates changes in copper (Cu) speciation that occur in sulfate-dominated basaltic and andesitic magmas equilibrated at oxygen fugacities (fO2′s) above the nickel-nickel oxide (NNO) buffer. Cu K-edge microfocused X-ray absorption fine structure spectroscopy (XAFS) data are presented from both natural and synthetic silicate glasses. Natural samples analyzed include olivine-hosted melt inclusions

The stable isotopic compositions of light n-alkanes, including methane, ethane, and propane, are often used to identify the sources and thermal maturity of natural gas samples. Though stable isotopic compositions of these molecules are commonly assumed to be controlled by kinetic isotope effects, recent studies have proposed both carbon and hydrogen isotopic equilibrium may also occur in some samples

A high specific surface area (SSA) typically signifies a superior adsorption capacity. Nevertheless, minerals with high SSAs tend to possess tiny pores that may not be accessible to relatively large (poly)oxyanionic metals. Herein, we assessed the adsorption of (poly)oxyanionic metals on 2-line and 6-line ferrihydrite and goethite with distinct SSAs and pore geometries. SSA was estimated by BET isotherm

Manganese (Mn) oxides are ubiquitous in natural systems, occurring as reactive nanoparticles with high surface area that play key roles in controlling the fate of trace elements and contaminants. These minerals may effectively scavenge arsenite [As(III)] from solution via oxidation and adsorption reactions, generating solid-phase Mn(II/III) as well as dissolved Mn(II). At redox interfaces, dissolved

The Devonian Period (∼359–419 Ma) documents significant environmental changes and marine species turnover, but whether these changes were linked to terrestrial weathering remains unknown. Here, we use lithium isotopes in brachiopods and bulk marine carbonates (δ7Licarb) from the Devonian Period to investigate changes in silicate weathering, which represents the primary long-term atmospheric CO2 sink

Viruses are the major drivers of global geochemical cycles through lysis of host bacteria. The release of cellular organic matter (OM) to the environment via viral lysis short-circuits the carbon flow from bacteria to higher trophic levels, a process known as the “viral shunt”. However, current understanding of bacteria–virus interactions is limited to the oceans. In sediments and soils, clay minerals

Molecular hydrogen (H2) is found in a variety of settings on and in the Earth from low-temperature sediments to hydrothermal vents, and is actively being considered as an energy resource for the transition to a green energy future. The hydrogen isotopic composition of H2, given as D/H ratios or δD, varies in nature by hundreds of per mil from ∼−800 ‰ in hydrothermal and sedimentary systems to ∼+450 ‰

Isotopic compositions of alkanes are typically assumed to be kinetically controlled, but recently it has been proposed that alkanes can isotopically equilibrate for both C and H isotopes during natural gas generation. Evaluation of this requires knowledge of the isotopic equilibrium between alkanes and other common hydrogen and carbon bearing species. Here we calculate isotopic equilibria within and

The hydrogen isotope ratios (δ2H) of mangrove leaf waxes are influenced by both precipitation and water salinity, making them promising proxies for paleohydrologic and paleosalinity reconstructions. However, the mechanism by which salinity affects 2H/1H fractionation remain unclear. While previous studies have shown that fractionation between source and leaf water pools is not the primary driver, it

This study investigated the cerium (Ce) geochemical composition in the regolith at Tanakami Mountain to assess the effectiveness of using Ce proxies for redox tracing during regolith formation. Based on the in-profile Ce isotope pattern, we divided this regolith into three different layers: I (0–2.0 m), II (2.0–5.0 m), and III layers (5.0–8.0 m). The regolith exhibits Ce anomalies (Ce/Ce∗) ranging

Understanding the weathering processes of minerals containing rare earth elements (REE) is crucial for unraveling the genesis of regolith-hosted REE deposits. However, the weathering mechanisms of bastnaesite, a primary REE carrier in parent rocks, remain uncertain. Discrepancies between field observations and thermodynamic calculations regarding its weatherability during mineral-groundwater interactions

Thallium isotope ratios (205Tl/203Tl) recovered from ancient marine shales are able to provide novel information about Earth’s ocean oxygenation history. Here we demonstrate the potential to extend this utility to the ancient carbonate record. We present Tl concentration and isotope ratio data for modern and geologically recent carbonates from the Great Bahama Bank that capture initial carbonate deposition

Clumped isotope-derived temperatures of various carbonate phases can be powerful tools for reconstructing past environmental signals such as surface and animal body temperatures, as well as calculating the oxygen isotope composition of ancient waters. However, solid-state isotope reordering can alter clumped isotope ordering and calculated temperatures without affecting the bulk carbon and oxygen isotopic

Cratonic lamproites are rare ultrapotassic rocks that occur in every continent and were emplaced over the last 2 billion years. Owing to their highly radiogenic Sr and unradiogenic Nd-Hf isotopic compositions along with enrichment in K and incompatible trace elements (e.g., Ba, Sr, Ti, Zr), lamproites are believed to be formed by melting geochemically enriched regions in the sub-continental lithospheric

Two types of mare basalt have been previously reported in the Luna-16 returned soil samples: dominant Intermediate-Ti basalts and minor Very-Low-Ti (VLT) basalts. The crystallization age of the main group of Intermediate-Ti basalts determined for 14 fragments by the Pb-Pb isochron approach is 3590.3 ± 9.4 Ma. Intermediate-Ti basalts are likely to represent the late episode of volcanism that occupies

We examine seven multicores obtained from the Cocos Ridge, including three potentially winnowed sites, and investigate how grain size fractionation affects 230ThXS- and 3HeET-derived mass accumulation rates (MARs). We find that bulk sediment 3HeET-derived MARs are a factor of 1.5–4.1 higher than 230ThXS-derived estimates in shallow winnowed sites, and 9–37 % lower than 230ThXS-derived estimates at

Assessing whether the lunar mantle retains sulfide, through episodes of magmatism, is important in tracking the origin and evolution of sulfur and other volatile and chalcophile elements on the Moon. To determine sulfur concentrations at sulfide saturation (SCSS) in the mantle conditions of young Chang’e-5 (CE-5) mare basalts, we conducted experiments with three possible CE-5 parental melt compositions

The origin of hydrocarbons is a central question in climate science, biogeochemistry, and astrobiology. Carbon and hydrogen isotopic ratios have been used to constrain hydrocarbon sources; however, studies based on these parameters alone are lacking. The recent development of a doubly substituted (“clumped”) ethane isotopologue (13C2H6) is expected to be useful in distinguishing between thermogenic

As the products of chemical sedimentation in the Archean oceans, Banded Iron Formations (BIFs) have been interpreted to record (bio)geochemical transitions in Earth’s ancient biosphere. Nonetheless, the effects of diagenesis and metamorphism over the long history of these rocks make it difficult to identify the minerals involved in the earliest stages of BIF formation. A series of recent studies has

Decadal-scale climate variability drives important fluctuations in nutrient availability and productivity in highly productive eastern boundary current upwelling ecosystems, but the relatively brief duration of most monitoring efforts limits understanding of these dynamics. When applied to high-resolution paleoarchives such as deep-sea proteinaceous coral skeletons, stable carbon and nitrogen isotope

Potassium-rich basalts provide valuable information about mantle heterogeneity and crust-mantle interaction because of their distinctive geochemical features. One of the long-standing issues regarding the origin of K-rich basalts is the nature of the K-rich mantle component required to generate such lavas. To provide further constraints on this issue, we present combined analyses of Mg, Zn and Fe isotopic

Ocean island basalts (OIB) offer valuable insights into the chemical composition of Earth’s mantle. Distinct radiogenic isotope compositions recorded in OIB have been used to characterize diverse mantle sources, indicating the presence of recycled crustal components within plume sources. Rubidium isotopes have the potential to trace crustal recycling, given the significant enrichment of Rb in the crust

Reconstructions of past changes in algal community composition provide important context for future alterations in biogeochemical cycling. However, many existing phytoplankton proxies are indicative of individual algal groups and are not fully representative of the whole community. Here, we evaluated hydrogen isotope ratios of algal lipids (δ2HLipid) as a potential proxy for phytoplankton community

Large volumes of fluid flow through aged oceanic crust. Given the scale of this water flux, the exchange of organic and inorganic carbon that it mediates between the crust and deep ocean can be significant. However, off-axis carbon fluxes in older oceanic crust are still poorly constrained because access to low-temperature fluids from this environment is limited. At North Pond, a sedimented depression

Permafrost thaw has the potential to release ancient particulate and dissolved organic matter that had been stored for thousands of years. Previous studies have shown that dissolved organic matter from permafrost is very labile and can be used by heterotrophic microbes close to the thaw area. However, it is unknown if ancient particulate organic matter can also be utilized. This study aims to investigate

Under geologically relevant conditions, Eu is a multivalent element, exhibiting divalent character in reduced systems and trivalent character in oxidized systems. Its mineral-melt and mineral-mineral partitioning behavior is sensitive to oxygen fugacity (fO2) and can be leveraged in oxybarometers that recover fO2s from natural samples if the partitioning behaviors of the divalent and trivalent species

Temperature regulates the metabolic rate of organisms and, together with salinity, determines seawater density, a key driver of ocean circulation and heat transport. The hydrogen isotope composition (2H/1H) of phytoplankton lipids has been shown to vary systematically with salinity and applied as a paleosalinity proxy in marine sediments. The influence of temperature on 2H/1H ratios of lipids from

Mg (and Sr) isotopes are applied as tracers of fresh and saline water sources and monitors of groundwater circulation in the hydrological-limnological system of the modern Lake Kinneret (the Sea of Galilee) and its late Miocene predecessors. The chemical and isotope compositions were measured in various water sources of modern Lake Kinneret and in limestones and dolostones that were deposited in fresh

Most chondrites are depleted in moderately volatile elements (MVE) relative to the bulk solar system composition represented by CI chondrites. Here we present high-precision isotope dilution data for 11 moderately volatile elements (S, Cu, Zn, Ga, Se, Ag, Cd, In, Sn, Te and Tl) together with Cd and Zn stable isotope compositions for carbonaceous, ordinary, enstatite and Rumuruti chondrites complemented

The partitioning of Sn between a mildly peraluminous granitic melt and saline aqueous fluids was studied at 800 °C and 150 MPa for oxygen fugacities ranging from the Fe-FeO to the Fe3O4-Fe2O3 buffer. Experiments were carried out in rapid-quench cold-seal pressure vessels using water as pressure medium. Oxygen fugacity was buffered by double capsules, except for oxygen fugacities about 0.5 to 1 log

Estuaries represent hotspots for organic matter cycling. Understanding the sources and fate of organic matter in estuaries is crucial for quantifying the transport of terrestrial organic carbon to the coastal ocean and air-sea carbon dioxide fluxes. Here we report the abundance and carbon isotopic signatures of bulk particulate organic matter (POM) as well as particulate amino sugars and amino acids

The C3 plant leaf wax δ13C (δ13Calk) is commonly used to reconstruct past climates. However, our understanding of how precipitation and temperature influence terrestrial C3 δ13Calk is limited. To address this gap, we investigated the δ13C of n-C29 alkane (δ13C29) of C3 terrestrial angiosperms in subtropical humid regions in China and compiled a global dataset. Results show a strong correlation between

Amorphous alkaline earth carbonates typically occur as metastable precursors of widespread crystalline phases. Despite their transient nature, the properties of the amorphous carbonates affect the attributes of the crystalline end-products. The lack of long-range ordering in the amorphous solids allows for the incorporation of various ions into their structures, resulting in a wider range of cation

Phosphate is crucial for the origin of life but typical environmental concentrations are too low for prebiotic synthesis of essential biomolecules like nucleic acids. However, evaporative, sodium-carbonate rich “soda” lakes can accumulate extreme phosphate levels sufficient for prebiotic synthesis. In modern soda lakes, this presumably requires small biological and inorganic (apatite mineral formation)

Monazite (XPO4 where X = light rare earth element) is one of the most important ore minerals for rare earth elements (REE) mined from carbonatites. This study explores the influence of pressure, temperature and melt composition on the solubility of monazite in carbonate melt using piston cylinder experiments. We aim to understand how such a highly soluble phosphate mineral may sometimes crystallise

Space weathering has long been known to alter the chemical and physical properties of the surfaces of airless bodies such as the Moon. The isotopic compositions of moderately volatile elements in lunar regolith samples could serve as sensitive tracers for assessing the intensity and duration of space weathering. In this study, we develop a new quantitative tool to study space weathering and constrain

Sulfate has been increasingly acknowledged as a key ligand for the mobilization and enrichment of rare earth elements (REEs). Here, we report the results of an investigation of the solubility of Sc2O3(s), scandium speciation, and the coordination geometry of scandium species in sulfate-bearing solutions using solubility experiments and ab initio molecular dynamics (AIMD) simulations. The investigation

Natural carbonates play a crucial role in the elucidation of several fundamental geochemical processes. In particular, their isotopic composition can be used as geothermometers to study paleoclimates or to constrain the global Ca cycle. However, experimental determination of equilibrium isotope fractionation factor for 26/24Mg and 44/40Ca is hindered by the many parameters involved in the precipitation

Basalt being the most dominant rock on the earth’s crust, contributes significantly to the global elemental cycle through weathering. In recent years, the potential of basalt weathering has been continuously scrutinized as a carbon dioxide removal (CDR) strategy. An accurate estimation of such large-scale processes requires a deeper insight into the mechanism controlling the basalt glass dissolution

The production of sulfuric acid (H2SO4) through the oxidation of reduced sulfur removes alkalinity from the ocean–atmosphere system and increases atmospheric carbon dioxide concentration (pCO2) over geologic timescales. In practice, quantifying CO2 changes due to H2SO4-driven weathering requires deciphering the sources of sulfate (SO42−) in river water. However, river SO42− concentrations ([SO42−])

Following the largest mass extinction of the Phanerozoic, the Early Triassic was characterized by a series of carbon cycle perturbations as revealed through multiple global carbon isotope excursions (CIEs). The mechanistic drivers behind these perturbations are a subject of debate due to limited records that differentiate terrestrial and marine carbon cycling processes. In this study, we focus on the

Iron is the most abundant element by weight in our planet, the dominant component of the core and the only major transition metal in the mantle. Its speciation in the present-day lower mantle remains one of the most controversial aspects to deal with in modelling the deep interiors of the Earth. Here, we present an unconventional approach that relies upon quantum mechanics and the bonding Bader theory

Magmatic-hydrothermal ore deposits are the world’s major source of molybdenum (Mo), yet the speciation of Mo in magmatic-hydrothermal fluids is still uncertain. We experimentally measured the solubility of molybdenite (MoS2) in H2O–S–NaCl ± HCl fluids at 800 °C, 200 MPa, with oxygen fugacity (fO2) controlled at ∼ Ni–NiO + 1 (∼NNO + 1), Re–ReO2 (RRO), MnO–Mn3O4 (MMO) and Fe3O4–Fe2O3 (HM) buffers. A

Most ureilites are melt residues from the partially melted Ureilite Parent Body. The Ureilite Parent Body was catastrophically disrupted at ∼ 5 Ma after Calcium-Aluminum rich Inclusions (CAI) while it was still hot and the ureilites provide a unique window into early solar system magmatic processing. One ureilitic trachyandesite, one cumulate, and 16 melt residue ureilites, all from the Almahata Sitta