This study investigates the trace element concentrations in the surface waters of four north-joining Himalayan tributaries of the Ganga river (Ramganga, Ghaghara, Gandak, and Kosi), highlighting the combined effects of geogenic processes and anthropogenic activities on trace element chemistry and water quality. A knowledge gap exists in understanding the sources of trace elements in these tributaries

The quality of water can significantly affect the regional water resources due to scarcity of potable water in industrial area. The purpose of this study was to explore potentially toxic trace elements (PTEs) contamination and their seasonal variations in different water sources within the coal mining area of the Mahan River command area, Central India. To achieve this, 96 water samples were collected

Bransfield Strait has been identified as a climate hotspot for understanding regional environmental changes with global impact. This study focuses on enhancing the understanding of carbon cycle dynamics and its interactions with hydrographic variables in Bransfield Strait, located on the northern Antarctic Peninsula. The stable carbon isotopes of dissolved inorganic carbon (δ13CDIC) were investigated

The geochemical data provided by the NASA MESSENGER spacecraft unveiled the geochemical heterogeneity of the volcanic crust of Mercury. Surprisingly, a high amount of sulfur was detected which combined with a low iron content, imply highly reduced conditions of parental magmas. Several variables (temperature, pressure, oxygen fugacity fO2, and to a lesser extent, melt composition) affect the solubility

Polyphosphate is formed by polyphosphate-accumulating organisms occurring in various terrestrial, freshwater, and marine ecosystems as well as industrial environments. Although polyphosphate-accumulating organisms and polyphosphate have been well studied in enhanced biological phosphorus (P) removal from wastewater treatment plants, their role in the internal P cycle of natural lakes remains unclear

Iron in shelf sediments is crucial in the marine iron cycle, significantly impacting the global C-S-Fe biogeochemical cycles. However, its fate in shelf sediments remains unclear. This study focuses on sediment core YSCW-1 from the Central Yellow Sea Mud, utilizing sediment grain size, redox-sensitive elements U and Mo, and iron speciation to explore the control mechanisms of redox states and sedimentary

The co-precipitation of dissolved organic matter (DOM) and phosphate with Fe(III) at the sediment-water interface plays a crucial role in the biogeochemical cycling of organic carbon (OC) and phosphate (P) in aquatic ecosystems. The fluxes of organic matter and phosphate may occur in a sequential manner. This study investigated how phosphate affected pre-equilibrated Fe(III)-humic acid (HA) co-precipitates

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

The iron and sulfur species play key roles in the transformation and immobilization of heavy metals (e.g., As(III)) in soil environments, while the underlying mechanism of these processes was not fully explored. In this study, the effects of sulfite (an important intermediate of sulfur species) on As(III) transformation induced by troilite (FeS) were investigated. Results showed that the presence of

The long-lasting pollution risks from sulfidic and metalliferous tailings are caused by the unpredictable weathering of unstable sulfidic minerals and associated release of potentially toxic soluble metals. The present study aims to investigate whether indigenous Acidithiobacillus consortia containing ferrous iron (Fe) and sulfide (S) oxidizing bacteria could be harnessed to accelerate the weathering

Phosphorites – made up of chemically precipitated authigenic apatite or composed of bioapatitic fossil remains – become enriched in a variety of trace elements such as Rare Earth Elements (REE), Cd, and U during diagenesis. The Cambrian-Ordovician phosphorites of the Baltica Paleobasin that are almost exclusively made up of fossilized remains of phosphatic brachiopod shells are, however, exceptional

Rodingites are metasomatic Ca-rich, Si-poor rocks typically formed on the seafloor during interaction of a gabbroic dike with seawater. However, rodingites are also common in exhumed metamorphic terranes, in which their formation and tectonic history are more complex. Here we measure the O, Ca, and Sr isotope compositions of seafloor and Alpine rodingites from various tectonic settings (obducted oceanic

Salinity, a key indicator of watermass conditions, is crucial for understanding the interactions between watermass conditions and climate change. This study presents novel insights into the paleosalinity variations with astronomically forced hydrological changes in Late Ordovician - Early Silurian marine shales of the Upper Yangtze area, based on high-resolution cyclostratigraphic analysis of the gamma-ray

The compositions of magnesium isotopes (δ26Mg) in the river systems are primarily controlled by the sources of Mg2+ and the processes of fractionation. However, how these factors govern the riverine δ26Mg values under different seasons remains unclear. To better understand the influences of weathering and hydrology on water chemistry, a systematic investigation was conducted on the seasonal variation

Quartz optically stimulated luminescence (OSL) sensitivity as well as some electron spin resonance (ESR) and cathodoluminescence (CL) signals have been empirically proposed as indicators for sediment provenance. Sensitivity is defined as luminescence emitted in response to a given dose per unit mass. While it is largely believed to be acquired by earth surface processes, recent studies bring evidence

The ‘big mantle wedge’ (BMW) beneath East Asia extends ∼1800 km inland from the trench, yet its formation time and mechanism remain enigmatic. A key challenge is linking subducted slabs to intraplate basaltic volcanism. Here, we present high-precision Ar-Ar dating and Sr-Nd-Hf-Pb isotopic analyses of Mesozoic basalt drill cores (2000–4500 m depth) from the Songliao Basin, NE China. Together with published

We present a method for in situ sulfur (S) isotope analysis in arbitrarily small areas (<1 μm2) within pyrite using ion imaging mode of nanoscale secondary ion mass spectrometry (NanoSIMS). The precision and accuracy of δ34S values obtained using this method were evaluated with reference pyrite with homogeneous S isotope ratios. The internal precision of the δ34S values in any region of interest (ROI)

Ponds can store large amounts of organic matter (OM) in their sediments, often accumulated over long periods of time. Sediment OM is largely protected from aerobic mineralization under water saturated conditions but are vulnerable when exposed to oxygen during periods of drought. As climate change progresses, drought periods are likely to occur more frequently and may affect OM mineralization, and

Hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers (OH-isoGDGTs), which exhibit similar behavior to regular isoprenoid GDGTs (isoGDGTs), have shown potential for reconstructing past seawater temperature than isoGDGTs in marginal seas due to their reduced impact from terrestrial inputs. However, there are marginal seas exhibit regional variability, such as water depth and seasonality bias

Authigenic pyrite commonly coexists with authigenic carbonate forming at marine methane seeps. Both pyrite and carbonate minerals are by-products of sulfate-driven anaerobic oxidation of methane (SD-AOM), the dominant biogeochemical process at seeps. The sulfur isotopic composition of pyrite has been extensively used to study the sulfur cycle and seepage activity in modern seep environments. However

Dissolved organic matter (DOM) is a natural ligand for heavy metal binding. Adsorption and oxidation of DOM by iron and/or manganese oxides may change its molecular composition and affect its binding with heavy metals, but the underlying mechanisms are still poorly understood. In this study, the effects of adsorption and oxidation of DOM by ferrihydrite and/or birnessite on its binding characteristics

Late Paleozoic seas on the North American Craton were subject to large fluctuations in elevation and facies in response to Gondwanan glacio-eustasy, but quantification of salinity variation has proven difficult. Here, we reconstruct salinity variation using two proxies (B/Ga and “excess boron” [Bxs]) through ten cyclothems spanning the upper Desmoinesian through Missourian stages (∼308–303 Ma) in a

Mantle-hosted granitoids (MHG) from the supra-subduction Samail ophiolite in Oman and the United Arab Emirates exhibit diverse compositions, highlighting variations in petrogenesis and source contributions. Previous isotopic data indicate these MHG originated through the interaction of sediment-derived with basaltic melts from an underthrust oceanic plate within the mantle wedge. The sedimentary contribution

The Finnish geological repository for spent nuclear fuel is being constructed at the ONKALO® underground facility in Olkiluoto Island. The bedrock is mainly migmatitic gneiss, including brittle fault zones where groundwater flows. An important process is the dissolution of chlorite, which releases Fe(II) that can lead to FeS precipitates and regulate dissolved HS− concentrations. Elevated HS− concentrations

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

Coexistence of mantle peridotites with distinct evolutionary histories is commonly observed in global ophiolites, especially in supra-subduction zone (SSZ) settings. The Dongco ophiolite in central Tibet has been interpreted to form within a Jurassic slow-spreading back-arc basin. This study presents comprehensive geochemical data of two types of peridotites from the Dongco ophiolite to investigate

The Neoproterozoic oxygenation event co-occurred with widespread phosphate deposition in sediments, the formation of concretionary structures, perturbations in stable carbon and sulphur isotope compositions, and possibly with the emergence of animals, all well-recorded in South China. However, the significance of concretionary structures in this context remains enigmatic. Occurrences of fossils inside

Carbonate green rust (GRCO3) is often found in suboxic and anoxic environments, and is known to be highly reactive towards dissolved metals and other aqueous compounds. Though the reactivity of GRCO3 towards a variety of aqueous compounds has been determined in previous studies, its reactivity under conditions relevant to modern and ancient marine environments has not been systematically explored.

The Ediacaran-Cambrian (E/C) transition in South China witnessed the evolution of early animals during an epoch of major oceanic environmental changes. Although the relationship of metazoan development to redox conditions has been investigated in many studies, the influence of watermass salinity has remained largely unexamined to date. Here, we report large salinity fluctuations in earliest Cambrian

Calcite is known to incorporate a range of non-constituent ions during its precipitation from aqueous solutions. Their concentrations (measured as E/Ca ratios, where E denotes the elemental forms of non-constituent ions) in calcite formed in seawater can serve as useful tools for paleoceanographic studies. But this requires concrete understanding of the incorporation patterns and their dependence to

Following the first series of this work, where the acidity constants of the two surface proton-reactive sites of goethite were found, as well as the capacitance values for each of the four previously well-characterized goethites, in this second part we report the successful simulation of the adsorption of two heavy metal cations [Pb(II) and Zn(II)] and an oxyanion (phosphate) of high affinity for the

Substantial quantities of heterogeneous sediments are transported into the mantle at subduction zones. However, geochemical signatures linked to recycled terrigenous sediments are almost absent in MORB and are only sporadically observed in some hotspot volcanoes. Therefore, identifying the provenance of the subducting sediments and their fate in the mantle is critical for unraveling the geochemical

Carbonate rocks are widespread and highly reactive, making their study a key topic for various environmental and anthropogenic issues. Dissolution of carbonate rocks is controlled by different factors, related to the fluid (chemical composition, pH, flow velocity) or the rock (mineral content, porosity, permeability, microstructure), and results in different dissolution patterns. To investigate the

The K/Ar and 40Ar/39Ar geochronometers are based on the naturally occurring radionuclide 40K. Their precision and accuracy are limited by uncertainties on the 40K decay constants and, in the case of the 40Ar/39Ar geochronometer, the isotopic composition of neutron fluence monitors. To address these limitations, we introduce a Bayesian calibration of the 40K decay scheme. We formulate robust priors

The thermodynamic and kinetic factors controlling the competitive heterogeneous nucleation and growth of ubiquitous metal carbonate and hydroxide phases are poorly understood. In this work, calcite (CaCO3) and magnesite (MgCO3) powders were reacted with NiCl2 (0–600 μM) for 7 days at 22 °C and 5 °C. The reacted powders were analyzed with X-ray photoelectron spectroscopy (XPS), scanning electron microscopy

Calculation of the molar standard state Gibbs energies of aqueous ions, G2o, at supercritical temperatures and pressures is a prerequisite for thermodynamic modeling of hydrothermal processes. Currently, such calculation is performed only with the well-known HKF model, and the development of alternative methods is highly desirable to avoid any possible bias. As a step in this direction, the author

The Francevillian Group, deposited during the Lomagundi carbon isotope excursion (LE), recently revealed evidence for complex and diverse Paleoproterozoic biota. This biota is preserved as pyritized and non-pyritized macrofossil structures hosted in black shale deposited in an oxygenated, open-marine environment. However, the timing of the LE, and the time when these macroscopic organisms evolved is

Isotope anomalies in meteorites reveal a fundamental dichotomy between Non-Carbonaceous- (NC) and Carbonaceous-type (CC) planetary bodies. Until now, this dichotomy is established for the major meteorite groups, representing about 36 distinct parent bodies. Ungrouped meteorites represent an even larger number of additional parent bodies, but whether they conform to the overall NC-CC dichotomy is unknown

Understanding phosphorus (P) dynamics in lake and marine sediments is critical for predicting P re-release into water bodies and its stable accumulation through burial. The distribution of P in sediments is influenced by inputs from rivers and groundwater, as well as post-depositional redistribution processes, such as sink switching and geochemical focusing. Although P, iron (Fe), and manganese (Mn)

The intricate nature and evolution of the zinc (Zn) biogeochemical cycle in modern and ancient sedimentary basins is a captivating scientific issue with regard to the complexity of Zn sources, diffusion paths and immobilisation processes. This article delves into assessing the sources, migration pathways, and concentration mechanisms of Zn in marine ooidal ironstone deposits of Western Siberia. The

The end-Triassic mass extinction (ETME) marks a pivotal event in Earth's history, characterized by major environmental changes in both marine and terrestrial settings and significant perturbations in the carbon and nitrogen biogeochemical cycles alongside extinction events. Here we employ high-resolution organic carbon isotopes (δ13Corg), nitrogen isotopes from bulk samples (δ15Nbulk), total organic

Several mantle plumes (Hawai‘i, Kerguelen, Pitcairn) produce ocean island basalt with enriched mantle I (EM-I) geochemical compositions. Hawai‘i is the most vigorous of these plumes, with the highest buoyancy flux. The isotopically enriched, EM-I-like compositions measured along the Hawaiian Island chain are limited to the Ko‘olau, Lāna‘i, and Kaho‘olawe volcanoes, which form the Enriched Loa geochemical

Amino acids detected in carbonaceous chondrites are commonly enriched in heavy isotopes of hydrogen compared to terrestrial counterparts. This is interpreted as the consequence of synthesis processes happening in cold extraterrestrial environments. However, the magnitude of this enrichment is variable among classes of chondrites and among individual amino acid in a given chondrite. In this study, we

Elemental proxies are widely used for analyzing watermass salinity in ancient shale and siliciclastic mudstone formations, but their application to limestones and marls has not yet been systematically tested. Unlike the Sr/Ba and S/TOC proxies, the B/Ga proxy offers considerable, albeit untested, potential for paleosalinity determinations in carbonate-bearing facies. To evaluate this potential, we

79Se is a key radionuclide concerned in the geological disposal of high-level radioactive waste. Unlike lower valent Se(IV), previous studies have reported that the reduction of aqueous Se(VI) into insoluble Se0 or FeSe2 by pyrite is challenging under ambient temperatures. Considering the thermal environment of radioactive waste repositories and the widespread presence of pyrite in the host rocks,

The concentration of Cesium in the aqueous magmatic fluid is widely used as an indicator for the degree of differentiation of the parental magma, which is fundamental for estimating the ore-forming potential of the fluid and characterizing the overall magmatic system. However, the fluid-melt partitioning behavior of Cs has not yet been well-characterized experimentally, posing some challenges in the

Intraplate magmatism has traditionally been linked to anomalously hot mantle (hotspots) transported upwards from deep-sourced mantle plumes. However, many intraplate magmatic provinces lack convincing evidence for a mantle-plume origin, and the Cameroon Volcanic Line (CVL) located on the West African continental margin is one such province. Despite being active for ca. 65 million years, it lacks the

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 >

Precise discrimination of basalt tectonic settings serves as a crucial methodological approach for providing insights into Earth's history. To address the limitations of traditional discrimination methods, which include high subjectivity due to reliance on expert experience and restricted precision resulting from simplistic comparative analysis of geochemical elements, we developed an innovative discrimination

Climate-related events and bark beetle outbreaks influenced hydrological dynamics and nitrogen cycling in three Central European forest catchments in the GEOMON network. Since 1994, distinct environmental phases were observed at studied catchments. Initially, nitrate (NO3⁻) concentrations declined at Anenský potok and Polomka due to reduced acid deposition, while remaining stable at Pluhův bor. From

Black carbon has been shown to suppress microbial methane production by promoting anaerobic oxidation of organic carbon, diverting electrons from methanogenesis. This finding represents a new process through which black carbon, such as wildfire char and biochar, can impact the climate. However, the mechanism and capacity of black carbon to support metabolism remained unclear. We hypothesized black

The Caribbean region is experiencing seasonal inundation of the shoreline by large mats of pelagic Sargassum spp. (Sargassum) leading to novel impacts to ecological communities. Where Sargassum becomes trapped along the shoreline, leachates turn the water a brown color, coined Sargassum Brown Tide (Sbt). We conducted monthly sampling at six sites along the offshore mangrove keys of Jobos Bay, PR between

H2O and CO2 are critical components for the development and sustainment of life on Earth and affect a wide variety of geological processes. It has been suggested that the presence of CO2 in the mantle could alter how H2O is stored and partitioned between minerals and melts, implying dramatic effects on both melting processes and H2O storage capacities of the Earth’s mantle. Eclogites, which are present

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