In seafloor hydrothermal systems, vent fluids usually contain elevated dissolved iron (Fe) that is significantly enriched relative to deep ocean seawater. It is commonly thought that Fe is preferentially transported in dense Cl-rich fluids due to the formation of aqueous Fe-Cl complexes. However, Fe enrichment in vapor-rich low-density fluids with low Cl concentrations (<550 mmol/kg) underscores the

Deep, carbonate-rich melts are key constituents of kimberlites and are crucial for understanding the cycle of volatile elements in the mantle. On the Siberian craton, the Udachnaya-East kimberlite hosts extremely well-preserved nodules composed of chlorides + carbonates + sulfates, that do not present any relict sedimentary textures. These salty nodules display textures that are commonly observed in

Culture experiments are uniquely suited for uncovering the fundamental factors controlling skeletal geochemistry because it is possible to explore conditions beyond what is found in the modern ocean and to decouple parameters that co-vary in nature. We cultured juvenile individuals of a cold-water coral (Balanophyllia elegans) in a set of experiments that decoupled carbonate chemistry parameters over

Oxygen-isotope measurements of fossil carbonates remain the most common method for paleoclimatic temperature reconstructions. A well-known limitation of this approach is the influence of the oxygen isotope composition of water in which mineralization occurs, which may vary significantly through space and time, and is often difficult to constrain precisely. Carbonate clumped-isotope thermometry is an

Understanding the mechanisms by which borosilicate glasses corrode in contact with aqueous solutions remains a challenge to the safety case for the geological disposal of vitrified high-level nuclear waste. Here, lithium isotope fingerprinting techniques were applied to the leachates of a simulant Magnox waste glass to probe the mechanisms of aqueous corrosion at both short and long timescales (6 hours

In 40Ar/39Ar geochronology, excess Ar is 40Ar that does not derive from the in situ radioactive decay of 40K, or from the measurable input of atmospheric Ar, and results in increased daughter-parent ratios that correspond to anomalously old apparent dates without geological age significance. Excess 40Ar is commonly identified by a saddle-shaped 40Ar/39Ar degassing spectrum. However, biotite from the

Pyrite corona nodules from the ∼2.7 Ga Kapai Slate, a thin, sulfidic carbonaceous shale horizon interbedded with basaltic lava flows in the Yilgarn Craton, Western Australia, have concentric compositional and isotopic zoning with distinctive textural differences between cores and mantles. The sieved-textured cores are enriched in highly compatible trace elements, incl. Ni, As, Ag, Te, Sb, Bi and Pb

Calcium-aluminum-rich inclusions (CAIs) are known as the oldest high-temperature mineral assemblages of the Solar System. The CAIs record thermal events that occurred during the earliest epochs of the Solar System formation in the form of heterogeneous oxygen isotopic distributions between and within their constituent minerals. Here, we explored the kinetics of oxygen isotope exchange during partial

The chemical composition of erupted basalts provides a record of the thermo-chemical state of their source region and the melting conditions that lead to their formation. Here we present the first probabilistic inversion framework capable of inverting both trace and major element data of mafic volcanic rocks to constrain mantle potential temperature, depth of melting, and major and trace element source

Several field-based studies have proposed that late-stage magmatic aqueous brines may be responsible for the transportation and redistribution of platinum-group elements (PGE) in mafic-ultramafic igneous systems. We experimentally studied the solubility of Pt in high-temperature aqueous brines as a function of oxygen fugacity (ƒO2), temperature (T), pH and total chloride concentration (Cltotal) in

Significant gaps in our understanding of the oceanic cycling of neodymium (Nd) and the other rare earth elements (REEs) remain despite decades of research. One important observation which has not been adequately explained is that the concentration of dissolved Nd typically increases with depth, similar to nutrient profiles, while Nd isotopes appear to reflect conservative water mass mixing in the intermediate

We determined the elemental and isotopic composition of Zn in sinking particles collected in the deep water of the northern South China Sea (NSCS) to investigate the relative contribution of various sources and assess their isotopic signatures. Using differentiable elemental ratios and δ66Zn of the potential sources, a mass balance approach estimates that anthropogenic aerosol Zn accounted for 64±10

Rubidium is an active element on Earth, but whether and how its isotopes fractionate during geological processes are not known yet. In this study, we present data showing large variations in δ87Rb in bulk samples and individual mineral species from a granite weathering profile in South China as well as in surrounding stream water. The bulk samples show that the mobility of Rb (τRbTiO2) fluctuates dramatically

Sorption of Mo to goethite and related iron (hydr)oxides plays an important role in controlling the mobility of Mo in soil and aquatic environments. We first performed ab-initio molecular dynamics (MD) simulations of Mo complexation at the goethite {1 0 1}-water interface. We find that molybdenum adsorbed on goethite mainly exists as the inner-sphere tetrahedral bidentate and monodentate corner-sharing

Most of the global Sn resources are from granite-related ore deposits, which form in response to cassiterite precipitation from hydrothermal fluids. However, the physical and chemical controls on the efficiency of Sn extraction from upper crustal plutons by exsolving magmatic fluids are still unclear. In this study, we determine the partition coefficient of Sn between aqueous fluids and granitic melts

We performed experiments to determine the solubility of Au and Pd in magmatic aqueous fluids as a function of oxygen fugacity (ƒO2), temperature (T), pH and total chloride concentration (Cltotal). Experiments were conducted at 800–1000 °C and 200 MPa in an externally-heated rapid-quench Molybdenum-Hafnium Carbide (MHC) cold-seal pressure vessel assembly. We employed a synthetic fluid inclusion (SFI)

Sorption reactions at the mineral/water interface control the fate and transport of trace metals in aqueous geochemical environments. While surface complexation theory is well established, understanding of surface induced precipitation at mineral/water interfaces is still limited. In this research, we employed a combination of macroscopic batch sorption studies, transmission electron microscopy (TEM)

Zinc (Zn) is a bioessential element whose cycling in the marine environment is closely linked to the biological pump. As a vital micronutrient, Zn is depleted in marine surface waters and enriched in deep waters. This has given rise to the longstanding hope that Zn could serve as a robust paleoproductivity proxy. There has been a recent focus on how Zn isotope signatures can be used to track the evolution

Coral skeletal Sr/Ca has valuable potential as a proxy of sea surface temperatures (SSTs). However seawater pCO2 can influence skeletal Sr incorporation and Sr/Ca-SST calibrations derived from present day corals may not be applicable to ancient specimens or older sections of modern corals deposited under lower seawater pCO2 than the present day. In this study we analysed skeletal Sr/Ca in multiple

Stable thallium (Tl) isotope data from organic-rich siliciclastic sedimentary rocks have the potential to track ocean redox state on a broad scale. Here, we report new Tl isotope data from the Mesoproterozoic Velkerri Formation (Roper Group) and the Paleoproterozoic Wollogorang Formation (Tawallah Group), McArthur Basin, Northern Territory, Australia, and interpret these in the context of rhenium-osmium

We present thermodynamic and empirical calculations for the iron-wüstite (IW) buffer applicable from 100 kPa to 100 GPa and from 1000 to 3000 K. The thermodynamic calculation self-consistently accounts for changing stoichiometry of iron-saturated wüstite as a function of temperature and pressure. In contrast to some previous models for calculating IW at high pressure, the model incorporates a thermodynamically

The surface of Mars has experienced progressive oxidation, resulting in the formation of sulfate minerals as evidenced from surface exploration missions. However, no clear evidence for the presence of sulfate minerals has been reported within Martian meteorites. This study examined sulfur speciation in impact glasses of three basaltic shergottites, Elephant Moraine (EETA) 79001, Larkman Nunatak (LAR)

Formation rates for various products of hydrogen sulfide oxidation by δ-MnO2 were studied as a function of pH, temperature, concentration of the reactants, and ionic strength at the environmentally-relevant conditions. The main goals of this work were studying the effects of these parameters on speciation of zero-valent sulfur, including individual polysulfides and revealing the mechanism of its formation

Although forming one unified class, orogenic gold deposits may be associated with a range of ore mineral assemblages controlled by a variety of gold deposition processes that have a direct impact on gold grade. Whereas, a better understanding of the deposition process may be critical for effective targeting of highly-endowed gold deposits, it is challenging to establish a direct comparison between

This study has analysed Li isotopes ratios from well-studied soil and pore water profiles from Iceland that have the same parent material but have experienced different degrees of chemical weathering. Thus, from least to most weathered, we have analysed vitrosols (V), gleyic andosols (GA), brown andosols (BA), Histosols (H) and Histic Andosols (HA). Although the most weathered H and HA soils have the

Clay mineral growth can directly affect the chemistry and permeability of many natural systems, including soils, marine sediments, Earth surface waters, geothermal powerplants and carbon dioxide storage sites. Notably, the sluggish precipitation of clay minerals has been hypothesised to hinder Earth surface weathering rates. To date, there are limited data on the rate of clay mineral growth and on

Subduction fluids play a crucial role in regulating long-term chemical cycles. Their characterisation is essential to understand the processes responsible for metasomatism, oxidation and melting of the mantle wedge. Both direct (fluid inclusion studies) and indirect (thermodynamic modelling) approaches to study subduction fluids have reliability issues due to the complexity of the investigated processes

Felsic rocks of the Erzgebirge in the Central European Variscides experienced ultra-high pressure metamorphism at ∼340 Ma, followed by nearly isothermal decompression during channel like rapid exhumation within ∼10 Ma. Despite the general time frame of exhumation and emplacement within mid-crustal levels is known, available geochronological data do not provide a detailed timescale of individual stages

Association of organic matter (OM) with mineral phases via co-precipitation is expected to be a widespread process in environments with high OM input and frequent mineral dissolution and re-precipitation. In contrast to surface area-limited adsorption processes, co-precipitation may allow for greater carbon (C) accumulation. However, the potential sub-micrometer scale structural and compositional differences

Noble gases are ideal natural tracers to characterize the storage, migration and origin of fluids in geological environments. They are chemically and biologically inert and therefore are only partially separated by physical processes including the one related to the molecular diffusion phenomenon, so called kinetic fractionation. However, its precise quantification is difficult to achieve and its modeling

Spectral and mineralogical analyses were performed using nine naturally hydrated and dehydrated carbonaceous chondrite samples which were classified into heating stages (HS) from I to IV based on previous X-ray diffraction results. In-situ heating of samples at 120–400 °C was performed during spectral measurements and successfully removed absorbed water and part of rehydrated water from chondrite samples

The origin of volatile element depletion in terrestrial planets and meteorites relative to a solar composition represented by CI carbonaceous chondrites remains an unsolved problem. The isotope compositions of moderately volatile elements may offer the possibility to distinguish between the various processes that may have caused this depletion (e.g., partial condensation or partial evaporation). We

To test the potential of deformation twins to record the age of impact events, micrometre-scale size mechanical twins in shocked monazite grains from three impact structures were analyzed by atom probe tomography (APT). Shocked monazite from Vredefort (South Africa; ∼300 km crater diameter), Araguainha (Brazil; ∼40 km diameter), and Woodleigh (Australia; 60 to 120 km diameter) were studied, all from

Physical heterogeneity in the subsurface creates preferential flowpaths that have the potential to impact mineral dissolution rates. Previous studies using numerical simulations have found that physical heterogeneity can reduce the mineral dissolution rate by an order of magnitude relative to homogeneous simulations. These findings indicate that the long-studied difference between laboratory dissolution

The non-classical crystallization pathway of carbonate minerals proceeds through the initial formation of an amorphous precursor phase and commonly takes place during biomineralization. Although the isotopic composition of marine calcifiers is often used to reconstruct paleo-environmental conditions, the impact of the crystallization pathway followed by these organisms on the isotope composition of

It is well known that volatiles such as water has significant influence on the properties of silicate melts. Carbon dioxide (CO2) is also an abundant volatile in deep Earth, however the effect of CO2 on the properties of polymerized melts, particularly the transport properties, are poorly understood. This is crucial for better understanding of the generation and migration of carbon bearing silicate

Recently developed methane clumped isotope techniques provides fresh and novel insights into methane biogeochemistry, which have been unobtainable through other techniques such as conventional stable isotope determinations and molecular composition measurements of hydrocarbons. Nonetheless, the governing processes and mechanisms which control the clumped isotope signatures (Δ13CH3D and Δ12CH2D2) of

Aluminosilicate glasses and melts are of paramount importance for geo- and materials sciences. They include most magmas, and are used to produce a wide variety of everyday materials, from windows to smartphone displays. Despite this importance, no general model exists with which to predict the atomic structure, thermodynamic and viscous properties of aluminosilicate melts. To address this, we introduce

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that are ubiquitous in the environment. Although the exact source organism is unknown, the distribution of brGDGTs in mineral soils, peats, and lake sediments is correlated with temperature through a decrease in the degree of methylation with increasing temperature. This empirical observation forms the basis of the

One of the prevailing hypotheses for the origin of the Younger Dryas (YD) cooling event is that it resulted from a bolide impact or airburst. Purported impact markers peak at or near the YD basal boundary layer at Northern Hemisphere locations. In this study, the 187Os/188Os ratios and highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd, Re) abundances in a well-dated sediment section through the Younger

We report detailed characterizations of the petrology, mineralogy, and noble gas signatures of Renazzo-type (CR) chondrites EET 92048, MIL 090657, NWA 801, and hydrothermally treated MIL 090657 samples to investigate primordial noble gases hosted by water-susceptible materials in aqueously less-altered CR chondrites. The noble gases were extracted by a stepwise heating method. The hydrothermal treatment

We conducted a petrologic study of apatite within eight unbrecciated, non-cumulate eucrites and two monomict, non-cumulate eucrites. These data were combined with previously published data to quantify the abundances of F, Cl, and H2O in the bulk silicate portion of asteroid 4 Vesta (BSV). Using a combination of apatite-based melt hygrometry/chlorometry and appropriately paired volatile/refractory element

Osmium isotopes, whole rock and mineral geochemical data from peridotite xenoliths from two Miocene McMurdo Volcanic Group cinder cones in the Transantarctic Mountains (TAM) in Southern Victoria Land, Antarctica, reveal that the underlying mantle preserves evidence for major mid-Proterozoic lithosphere formation despite the crust being dominated by late Neoproterozoic-Ordovician (~0.65–0.47 Ga) rocks

Interactions between organic and detrital mineral phases strongly influence both the dispersal and accumulation of terrestrial organic carbon (OC) in continental margin sediments. Yet the complex interplay among biological, chemical, and physical processes limits our understanding of how organo-mineral interactions evolve during sediment transfer and burial. In particular, diverse OC sources and complex

Sediment-hosted marine sulfur cycling has played a significant role in regulating Earth’s surface chemistry over our planet’s history. Microbially-mediated reactions involving sulfur are often accompanied by sulfur isotope fractionation that, in turn, is captured by sulfate and sulfide minerals, providing the opportunity to track changes in the microbial utilization of sulfur and thus the marine sulfur

Fluid is a key agent for the mass transfer between the subducting slab and the mantle wedge, which greatly affects the evolution of the crust-mantle system at convergent plate boundaries. A geochemical study was carried out for coesite-bearing jadeite quartzite and its country rock granitic gneiss from the Dora Maira Massif in the Western Alps. The results provide new insights into the composition

40Ar/39Ar laser incremental-heating geochronology of whole-rock fragments and minerals from primitive subalkaline mafic dykes from the Cabo Frio Tectonic Domain, southeastern Brazil, reveal a complex combination of intrusive ages, apparent ages affected by excess argon, and ages that record late-stage hydrothermal alteration. Incremental-heating analysis of encapsulated magmatic amphibole-biotite clusters

Enrichments in light REE without concomitant enrichments in high-field-strength elements in mantle peridotites are usually attributed to inputs from carbonate-rich melts and referred to as ‘carbonatite’ metasomatism as opposed to interaction with evolved silicate melts. Alternatively, both enrichment types are ascribed to percolating volatile-bearing mafic liquids whose chemical signatures evolve from

The 135 Ma Paraná-Etendeka Large Igneous Province (PELIP) is one of the largest areas of continental flood basalt (CFB) volcanism in the world and is widely agreed to be a product of intracontinental melts related to thermal anomalies from the Tristan mantle plume. The province rifted during the break-up of Gondwana, as the plume transitioned into an oceanic geodynamic environment. This study reports

The elemental and isotopic fractionation of lithium between inorganic calcite and aqueous solutions has been measured as a function of solution chemistry in mixed CaCl2-NaHCO3 aqueous solutions spanning a range of pH from ~6 to ~9.5 at room temperature. Vaterite added to the solution recrystallized to calcite with limited change in solution chemistry. With this experimental design solution pH and Na/Ca

To constrain the behavior of K isotopes during the low-temperature alteration of oceanic crust and reveal its impact on the global K cycle, we measured the K isotopic compositions of 49 fresh and altered basalts recovered from the Integrated Ocean Drilling Program (IODP) Sites U1365 (~100 Ma) and U1368 (~13.5 Ma) in the South Pacific Ocean. The measured basalts representing the uppermost oceanic crust

Earth’s Great Oxidation Event (GOE), ca. 2.5 to 2.0 Ga, was one of the most extreme environmental perturbations in the history of the planet. In addition to the first sustained accumulation of O2 in the atmosphere, the latter half of the GOE is associated with a very large positive carbon isotope excursion, both in terms of magnitude and inferred duration. The end of the GOE may have been associated

The abundance of 18O isotopes and 13C-18O isotopic “clumps” (measured as δ18O and Δ47, respectively) in carbonate minerals have been used to infer mineral formation temperatures. An inherent requirement or assumption for these paleothermometers is mineral formation in isotopic equilibrium. Yet, apparent disequilibrium is not uncommon in biogenic and abiogenic carbonates formed in nature and in synthetic

The asthenosphere beneath both ancient and modern oceans is highly heterogeneous owing to the recycling of continental, sub-arc, or sub-oceanic mantle domains and subducted oceanic crust and pelagic sediments. The identification and discrimination of those “old” mantle domains are important for understanding of the generation of oceanic crust and the tectonic setting of ophiolites. Here we report geochemical

Lithium (Li) isotopes signatures in sedimentary archives are promising proxies to reconstruct paleo-weathering rates and paleo-seawater composition. Nonetheless, the interpretation of the seawater Li isotope composition evolution over the Cenozoic is still debated. In this aim, the study of large rivers can provide constraints for continental weathering flux to the ocean. However, in the recent past

40Ar/39Ar geochronology is one of the most important techniques for constraining the timing of basaltic events due to the paucity of suitable minerals in basalts for other geochronological techniques such as U–Pb (e.g., zircon, baddeleyite). Among a variety of materials from basaltic rocks that have been used for 40Ar/39Ar dating, plagioclase is the most important due to its common presence in basalts

Chondrules are sub-millimetric spheroids that are ubiquitous in chondrites and whose formation mechanism remains elusive. Textural and oxygen isotopic characteristics of chondrules in carbonaceous chondrites (CCs) suggest that they result from the recycling of isotopically heterogeneous early-condensed precursors via gas-melt interactions. Here, we report high-resolution X-ray elemental maps and in

We report the first zinc isotope data (expressed as δ66Zn relative to the JMC-Lyon standard) for chromian spinels (Cr-spinels) and coexisting olivines in oceanic peridotites. All spinel-olivine pairs fall on the 1:1 fractionation line in the diagram of δ66Znspinel versus δ66Znolivine, suggesting equilibrium isotope fractionation. Cr-spinels are always isotopically lighter than coexisting olivines

Flow-only and coupled flow-diffusion experiments at 95 °C and 100 bars pCO2 carried out in micro-capillary tubes packed with forsterite mineral grains were used to constrain a coupled classical heterogeneous nucleation and crystal growth reactive transport model describing the formation of secondary magnesite. The study made use of a novel experimental setup in which one capillary tube for flow is

The Mg and SO4 content of naturally occurring calcite are routinely used as paleoenvironmental proxies. Yet little is known about the mechanisms governing the presence of these ions in carbonate minerals when their formation proceeds via an amorphous precursor. To address this, the transformation of Mg-free amorphous calcium carbonate (ACC) into nanocrystalline high-Mg calcite (HMC) was experimentally