Sodium-bicarbonate HCO3–Na (sodic) groundwaters exist throughout southeastern West Siberia at approximate depths from 50–300 m to 1.0–2.3 km in Mesozoic-Cenozoic sediments. They belong to five main types of fresh (I), brackish (II), high-pH low-saline (III), coal-related saline (IV), and carbonated (V) waters that differ in composition, as well as in depth and lateral extent. Waters of types I and

Deep subsurface biofilms are estimated to host the majority of prokaryotic life on Earth, yet fundamental aspects of their ecology remain unknown. An inherent difficulty in studying subsurface biofilms is that of sample acquisition. While samples from marine and terrestrial deep subsurface fluids have revealed abundant and diverse microbial life, limited work has described the corresponding biofilms

The discovery of mid‐Proterozoic (1.8–0.8 billion years ago, Ga) indigenous biomarkers is a challenge, since biologically informative molecules of such antiquity are commonly destroyed by metamorphism or overprinted by drilling fluids and other anthropogenic petroleum products. Previously, the oldest clearly indigenous biomarkers were reported from the 1.64 Ga Barney Creek Formation in the northern

The Cretaceous Yunshan caldera complex in SE China consists of an unusual coexisting assemblage of peraluminous and peralkaline rhyolites and a resurgent intra-caldera porphyritic quartz monzonite. In this study, we use zircon trace element data to study the compositional differences of zircons from cogenetic magmas and to track the evolution of the entire magmatic system. Our results indicate that

Alteration of oceanic lithosphere plays an important role in the global element cycling due to its dominant abundance on the Earth's surface. The formation of rodingites, a Ca rich lithology that occurs intimately associated with Ca depleted serpentinite complexes, is a widespread process during strong alteration of ocean-floor lithologies and may represent a key process that influences the global

Vanadium (V) has been a useful trace metal in describing Earth’s biogeochemical cycling and development of industrial processes; however, V has recently been recognized as a potential contaminant of concern. Although Fe (oxyhydr)oxides are important sinks for aqueous V in soils and sediments, our understanding of adsorption mechanisms is currently limited to mononuclear species (i.e., HxVO4(3–x)–)

Calcium (Ca) and magnesium (Mg) are the most abundant alkaline-earth metal ions in nature and their interaction with ferrihydrite (Fh) affects the geochemical cycling of relevant ions, including phosphate (PO4). The interfacial interactions of Ca and Mg (M2+) with PO4 have not been analyzed yet for freshly-precipitated Fh. Here, we studied experimentally this interaction in binary M2+–PO4 systems over

Geological gas seepage in petroleum-bearing sedimentary basins is an important natural source of atmospheric methane. In methane budget models, geological emissions are generally considered constant over time, not affecting decadal atmospheric methane changes. Here, we report the case of a considerable sub-decadal variation of methane seepage from one of the largest thermogenic gas seep sites in Europe

The late Neogene marls from the Lorca, Murcia and Vera basins in S-E. Spain contains abundant dolomite nodules that were formed due to intense methane-rich fluid migration. The pathways for these fluids are evidenced by dense networks of fractures that are crossing the sedimentary layers and eventually the dolomite nodules. The fractures are generally filled by secondary fibrous gypsum that form veins

Geochemistry of volatiles in active volcanoes provides insights into the magmatic processes and evolution at depth, such as magma evolution and degassing, which can be implemented into volcanic hazards assessment. Deception Island is one of the most active volcanoes in Antarctica, with more than twenty explosive eruptions documented over the past two centuries. Hydrogen and oxygen isotopic variations

Sulfate (SO42–) incorporated into calcium carbonate minerals enables measurements of sulfur (S) isotope ratios in carbonate rocks. This Carbonate Associated Sulfate (CAS) in marine carbonate minerals is thought to faithfully represent the S isotope composition of the seawater sulfate incorporated into the mineral, with little or no S isotope fractionation in the process. However, comparison between

In continental volcanic settings, abundant carbonate precipitation can occur with atypical facies compared to marine settings. The (bio-)chemical processes responsible for their development and early diagenesis are typically complex and not fully understood. In the Bolivian Altiplano, Laguna Pastos Grandes hosts a 40-km2 carbonate platform with a great diversity of facies and provides an ideal natural

Among solar system materials there are variable degrees of depletion in moderately volatile elements (MVEs, such as Na, K, Rb, Cu, and Zn) relative to the proto-solar composition. Whether these depletions are due to nebular and/or parent-body (asteroidal or planetary) processes is still under debate. In order to help decipher the MVE abundances in early solar system materials, we conducted a systematic

Titan, Saturn’s largest satellite, is the only icy moon with a dense atmosphere. This atmosphere is composed mainly of N2. Methane, the second most abundant constituent, would be depleted in only 30-100 Myr by active photochemistry, suggesting replenishment from Titan’s interior. Cassini-Huygens observations suggest that ammonia is the main source of Titan’s atmospheric N2. Under Titan’s near-surface

Produced water is a byproduct of oil and gas production. The chemistry of produced water may provide information about the source of the fluid and its evolution, leading to an improved understanding of the hydrology of petroleum systems. In this study, samples from 19 wells from the Tuscaloosa Marine Shale (TMS) in Mississippi and Louisiana, USA were analyzed for their major and trace element compositions

In this paper, the QS-1 sediments (3.64 m long; at 1500 m water depth) collected from the Qiongdongnan Basin were used to analyze the relationship between sedimentary geochemical anomalies and methane seepage. Mo-U covariation, Ce anomaly, and Mg/Ca-Sr/Ca end-member model were analyzed to identify the variations of redox environment and authigenic carbonate precipitation, finally constructing the methane

The Genesis mission captured Solar Wind (SW) and delivered it to Earth for laboratory analyses. Due to advanced mass spectrometric techniques developed specifically for analyses of returned Genesis SW-collectors, SW-oxygen, nitrogen and noble gas isotopes have been successfully measured providing new insights for cosmo- and geochemistry. SW-Xe collected by Genesis is the heaviest and the least abundant

Organic and inorganic stable isotopes of lacustrine carbonate sediments are commonly used in reconstructions of ancient terrestrial ecosystems and environments. Microbial activity and local hydrological inputs can alter porewater chemistry (e.g., pH, alkalinity) and isotopic composition (e.g., δ18Owater, δ13CDIC), which in turn has the potential to impact the stable isotopic compositions recorded and

Abstract The frequently observed discrepancy between estimations of N2O emissions at regional or global scale based either on field data or inventories (bottom-up) or on direct atmospheric observations (top-down) suggests that riparian areas and river surfaces play a significant role as hot spots of emission. We developed a modeling procedure to assess N2O emissions occurring during the transfer of

The selenium (Se) isotope system has been proposed as a redox proxy in environmental and paleoceanographic studies. However, Se isotope exchange among various Se species can potentially interfere with redox-related isotope signatures, and is still poorly understood. In this work, we investigated Se isotope exchange kinetics and equilibrium fractionations between aqueous Se(IV) and Se(VI) under various

The coupled effects of pH and ionic strength impact a variety of geochemical processes in the subsurface. In this study, we investigate the interactions of H+ and major ions at the surface-solution interface of silica porous media under advection-dominated flow-through conditions. A series of 21 column experiments were performed by systematically injecting solutions of different pH and ionic strengths

Abstract Chemical composition of melt-rocks from several localities around proposed post-Eocene Krk impact structure in Croatian carbonate (a.k.a. External) Dinarides was analyzed by three spectroscopic methods to decipher their source lithology. The utilized spectroscopic methods were ICP-AES, TXRF and PIXE+EBS, and their applicability for the analysis of melt-rocks was tested. The three analytical

Abstract— The mean concentrations of volatiles, major, and trace elements are estimated in the magmatic melts of Kamchatka based on an our database that includes analyses of melt inclusions and quenched glasses of rocks for 75 elements (the database comprised 1 900 000 analyses as of late 2018). The determined concentrations are compared with analogous characteristics of melts from island arcs and

Abstract In mainland China, there are large surface areas covered with shallow overburden (Regolith thickness < 100 m). Geological mapping is difficult here as there is not enough exposed bedrock. In this paper, we transfer geochemical and geophysical data to characteristics, and use it in geological mapping to identify the underlying bedrock. Above all, we define the “represent area of one geochemical

Abstract— The paper discusses the forms of anthropogenic radionuclides in natural waters at radiation-contaminated territories. The data were obtained using techniques of cascade filtration and flow field flow fractionation coupled with multi-detector analysis. The size and nature of the colloid and suspended particles in the tunnel waters were determined in the range of 1 to 10 000 nm. The average

Abstract—The composition of compounds employed as markers for anoxia in the photic layer of the sedimentation basin is studied in samples from Upper Devonian domanik-type sediments (Sargaevian, Semilukian, and Mendymian horizons, Famennian stage), which are widespread over the Volga–Urals basin. The studies were carried out along the north-south section spanning the northern and central parts of the

Abstract— The conditions of genesis of diamondiferous ultrabasic and basic rocks from xenoliths in kimberlite were studied by combining the data from analytical investigations of their mineral phases and experimental results of the study of melting relations in the diamond-forming mineral systems of the upper mantle. The compositions of minerals in some samples of metasomatized diamondiferous eclogite

Abstract— The paper presents analysis of the accumulation of toxic and vital chemical elements in discrete links of the food chain under conditions of a biogeochemical province in relation to the accumulation of phytochelatins and metallothioneins in the leaves of white birch (Betula pubescens). Gradients of metal concentrations are determined in the soils with increasing distance from the Unal tailing

Abstract—The base-metal (70–75 wt %) and tin–sulfide (10–15 wt %) deposits are the main indium suppliers in the world. However, the causes and conditions of In accumulation in the ores of these deposits are still unclear. To shed light on this problem, we simulated the physicochemical conditions of formation of base metal and tin–sulfide ores with elevated indium content. For this purpose, the average

Abstract—The article discusses the distribution of rare-earth elements in the igneous and metasomatic rocks of the Murovdag ore district of the Lesser Caucasus. It has been established that the metasomatites and host rocks of the Murovdag ore district are characterized by the predominance of light rare-earth elements over heavy ones. The whole complex of the data obtained indicates that the components

Abstract—The study aims to contribute to submarine hydrothermal particle geochemistry knowledge on the central part of the Hellenic Volcanic Arc. Hydrothermal fluids collected by scuba diving from active shallow hydrothermal venting areas on Milos Island in the Aegean Sea in East Mediterranean. Analysis carried out in suspended particles for Fe, Mn, Cu, Pb, Cd, Ca, Ba, Sr, Li, Al and Si. During sampling

Abstract—Analysis of zircons from Early Paleozoic calc-alkaline granitoids in the central part of the Angara–Vitim Batholith revealed two geochemically different zircon varieties. Central unaltered domains have homogenous BSE images, “magmatic” REE distribution pattern, and the moderate content of trace elements. Altered zones of zircon are characterized by more gentle patterns owing to the growth

Abstract—Data on the influx and behavior of humus substances in natural waters are considered. The widest spread methods of analyzing physicochemical properties of natural polymers causing their interaction with metal ions are analyzed. The concept of metal complexation with humus substances at different chemical equilibria is developed on the basis of original and an available literature review evaluating

Abstract The shock-explosive processing of rocks by micrometeorite and meteorite bombardment on the surface of the Moon and other airless bodies of the solar system is a dominant geological and geochemical process that produces the loose layer of regolith. The paper presents results of modeling the process of a micrometeorite impact using a millisecond laser. The targets in the experiment were a sample

Abstract—The kinetics of Np(VI and V) reduction was studied in model underground water in the presence of bacteria, isolated from from deep-injection disposal of liquid radioactive wastes of Siberian Chemical Plant. Obtained data indicate a chemical instability of Np(VI) in the studied system. The reduction of neptunium (V) depended on its initial concentration and the presence of microorganisms. In

Abstract The purpose of equivalence assessement is to recognize a significant shift between values of the same variables (elements in geochemical surveys) in two datasets. To merge two or more independent datasets that are somehow linked together to create a new integrated dataset, the significance of the difference between datasets must be determined. Merging data originated from two or more geochemical

Abstract This paper continues a series of our earlier publications summarizing literature data on the physicochemical parameters and chemical composition of fluids at endogenic gold deposits and presents estimated average values of the temperature, pressure, and salinity of fluids, and variations in these parameters, at Mesozoic gold deposits. Parameters of mineralizing fluids at the Mesozoic deposits

Abstract— A physicochemical study of natural hydrous magnesium orthophosphates bobierrite Mg3[PO4]2 · 8H2O and kovdorskite Mg2[PO4](OH) · 3H2O from the Kovdor carbonatite massif, Kola Peninsula, Russia, was carried out using X-ray diffraction, infrared spectroscopy, Raman spectroscopy, and thermal analysis. The enthalpies of dehydration of the minerals were measured using a NETZSCH DSC 204 F1 differential

Abstract— A procedure was proposed for the direct determination of changes in the composition of the adsorbed complex of freshwater terrigenous material upon its entry into a marine environment. It was shown that changes in the composition of the adsorbed complex calculated from the difference of major cation contents before and after contact with seawater closely match data obtained by the proposed

Abstract—Carbon isotope composition was analyzed in С21n‑alkylbenzene and n‑alklylnaphthalene from five Upper Devonian oils of the Timan–Pechora Basin. In spite of the variations in carbon isotope composition, the difference in δ13C between n‑alkylbenzene and n‑alklylnaphthalene is relatively constant and accounts for, on average, 2.7‰. It is generally accepted that these compounds were derived from

Abstract—Lithological-facies mapping of Pleistocene sediments of pelagic zone and ten key areas of the Pacific submarine margins allowed us to compile the review maps of the Neo- and Eopleistocene sediments for almost 90% of ocean basin area. The comparative analysis of quantitative sedimentation parameters for the Pleistocene sediments of the pelagic and continental margins revealed an increase of

The Technology of Horizontal Silicate Barriers (TFHB) is an injection technology in which a solution of sodium silicate is introduced into the aquifer, close to the water table, while below CO2 is injected and catalyzes silicate gelation. Silicate gel decreases the aquifer permeability and forms a horizontal barrier. In this work, by means of geochemical modeling, we indicate potential interactions

Cold seep environments are characterized by methane-rich fluid migration and discharge at the seafloor. These environments are also intimately linked to microbial communities, which oxidize methane anaerobically, increase alkalinity and promote authigenic carbonate precipitation. We have analyzed a suite of methane-derived authigenic carbonate (MDAC) crusts from the North and Barents Sea using stable

We report the calcium isotope fractionation during the microbially-induced precipitation of calcium carbonate minerals in pure cultures of the marine sulfate-reducing bacterium Desulfovibrio bizertensis. These data are used to explore how the calcium isotope fractionation factor during microbially-induced carbonate mineral precipitation differs from the better-constrained calcium isotope fractionation

In this study, molecular dynamics simulations were performed to investigate the effects of montmorillonite with different surface cations (i.e., Na+, K+, and Ca2+) on CH4 hydrate formation. The results showed that CH4 hydrate cages are mainly formed beyond the montmorillonite surface. The inner-sphere adsorption of K+ and the outer-sphere adsorption of Na+ and Ca2+ occurred on the montmorillonite surface

Constraints on Precambrian ocean chemistry are dependent upon sediment geochemistry. However, diagenesis and metamorphism can destroy primary biosignatures, making it difficult to consider biology when interpreting geochemical data. Modern analogues for ancient ecosystems can be useful tools for identifying how sediment geochemistry records an active biosphere. The Middle Island Sinkhole (MIS) in Lake

Methane emissions from peat bogs are mitigated by methanotrophs, which live in symbiosis with peat moss (e.g. Sphagnum). Here, we investigate the influence of temperature and resultant changes in methane fluxes on Sphagnum and methanotroph‐related biomarkers, evaluating their potential as proxies in ancient bogs. A pulse‐chase experiment using 13C‐labelled methane in the field clearly showed label

Understanding weathering processes in clay formations is an issue of primary importance for the preservation of our natural environment. Reactive-transport modeling used to simulate weathering of clay formations has indicated that reactive gases (CO2 and O2) are major parameters in controlling weathering processes. The Lower Cretaceous Tégulines marine-clay formation outcropping in the area of Brienne-le-Chateau

Soil carbon plays a key role in agriculture and ecosystem. Semi-arid regions cover many parts of China, holding a carbon pool that should not be ignored. Thus, systematic studies of the carbon distribution and variation in semi-arid regions are necessary. In this study, we comprehensively analyzed the factors that influence the distribution and variation in soil carbon covering area over 0.92 × 106 km2

Shale gas produced water has a large number of inorganic compounds, originating from the shale layer and the fracturing fluid. Especially, the Marcellus shale gas produced water contains a relatively high concentration of lithium, one of the important metals in various industries; as a result, there have been several studies on recovering lithium from the produced water. However, the fluid also includes

Abstract The properties of the atmospheric aerosols depend on the source region and on the modifications that occur during their transport in the air. We have studied physical and chemical properties of aerosols along with their sink mechanism over two locations in southwest India, an urban site (Pune) and well-established climate observatory at Sinhagad (SINH), which represents rural and high altitude

Abstract The Walker and Syers model predict that phosphorus (P) availability decreases with time leading to a final stage known as retrogression. We tested the validity of the Walker and Syers model in the Canary Islands, a soil chronosequence ranging from 300 years to 11 million years under recurrent episodes of atmospheric dust-containing P inputs. In particular, we compared our results with those

Organic matter (OM) is often associated with Fe (hydr)oxides such as ferrihydrite (Fh) in soils and sediments, forming binary Fh-OM complexes. Microbial reduction of Fh results in destabilization of the complexes and mineral/OM transformation. However, little is known about the role of clay minerals in such processes, despite their common co-existence with Fh and OM in natural environments. Here Fh-OM

We conducted experiments at high pressure (P) and temperature (T) to measure hydrogen solubility in plagioclase (Pl) with a range of compositions (An15 to An94). Experiments were run at 700-850 °C, 0.5 GPa, and fO2close to either the Ni-NiO (NNO) or iron-wüstite (IW) oxygen buffers. Experiments at 700 °C on An15 (containing 0.03 wt% FeO) reveal no dependence of H solubility on fO2 between IW and NNO