Cryogenic cave carbonates (CCC) are speleothems that form under freezing conditions and provide crucial insights into past cold environments and cryogenic processes. Traditionally, CCC have been classified into two categories: fine-grained CCC (hereafter CCC-f) and coarse-grained CCC (hereafter CCC-c), primarily based on particle size and stable isotopic composition. However, recent observations from

Hydrothermal vents and cold seeps occur in tectonically active areas and along continental margins. They harbor diverse chemoautotrophic organisms, providing valuable insights into fluid types and trophic dynamics. Interestingly, certain mussel species can inhabit both ecosystems, deriving energy from the aerobic oxidation of methane (AeOM) or sulfur oxidation. However, the geochemical fingerprinting

The Sunda Shelf receives substantial sediment inputs from the Tibetan Plateau and Southeast Asia's mountainous islands, impacting southern South China Sea sedimentation during Quaternary sea-level changes. Due to multiple river basins contributing to the shelf, the origin and distribution of its surface sediments remain poorly defined. Here, we analyzed major and trace element concentrations and Nd

Mantle plume isotopic compositions are useful for understanding the processes that produce heterogeneity within the mantle. Thallium (Tl) isotopic compositions are uniquely well suited for tracing pelagic sediments and low-temperature altered oceanic crust in the mantle. We measured the Tl isotopic composition of Paleocene lavas on Baffin Island, the earliest lavas associated with the Iceland mantle

The Toarcian Oceanic Anoxic Event (T-OAE) represents a significant disturbance of the Earth's atmosphere-ocean system in the Early Jurassic, and its response in lacustrine systems has been widely studied in recent years. However, the impact of T-OAE on the subsequent environmental changes and nitrogen cycling patterns in lacustrine systems are poorly understood. This study investigated the paleoenvironmental

Mantle xenoliths provide a direct window into the subcontinental lithospheric mantle (SCLM) beneath Archean cratons. Age constraints on the melting, metasomatism and deformation that have affected the SCLM are crucial for developing insight into continental dynamics and craton development. Obtaining constraints is nevertheless difficult. Garnet geochronology – and Lu-Hf geochronology in particular

Ferromanganese (Fe-Mn) nodules are marine chemical sediments that represent unique archives for the reconstruction of ambient seawater conditions. This record is limited from modern to Cenozoic times due to the instability of Fe-Mn oxides during burial and subduction of the oceanic crust and overlying sediments. However, almost uncharacterized Fe-Mn nodules exist in Jurassic sedimentary strata throughout

Metal-mining pollution impacts estuarine systems, where sediments with high available toxic metal concentrations precipitate. In the Ría de Huelva estuary (SW Spain), the metal-rich acidic water of the Tinto River (headwater pH = 2.2 and electrical conductivity -EC- = 25.8 mS cm−1) interacts with saline-alkaline seawater of the Atlantic Ocean (pH = 7.87, EC = 55.2 mS cm−1). This study analyses the

Carbonate-evaporite successions can serve as important hydrocarbon reservoirs. However, the unique petrophysical properties of evaporites and various carbonate-evaporite lithological associations have impeded understanding of the complex fluid-rock interactions and diagenetic evolution of these reservoirs. Here we present numerical modeling of the diagenetic mineral-porosity evolution in various f

Illite, a clay mineral formed during diagenesis and low-grade metamorphism, can be dated using the K-Ar method to reconstruct the chronological history of sedimentary basins, fault and fold formation, and hydrothermal alterations. However, conventional K-Ar and Ar-Ar dating of illite faces challenges due to the clay's small grain size, hygroscopicity, limited availability in finer fractions, and other

Subduction recycled components can be incorporated into the mantle through aqueous solution/melt metasomatism; however, tracing the source and nature of metasomatic agents, as well as reconstructing the melting reactions of metasomatic mantles, has consistently posed significant challenges. In this work, we performed an extensive study involving petrology, geochronology, mineral chemistry, geochemistry

This study presents a comprehensive investigation of petrography, clumped isotope thermometry (T-∆47), and NanoSIMS sulfur isotopic analysis of pyrites for the basal Doushantuo cap carbonates from the Jiulongwan (JLW) section. The majority of the analyzed pyrites originate from reduction of marine sulfates, primarily through thermochemical sulfate reduction (TSR), with minor contributions from microbial

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

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

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

Alteration of silicate phases in marine sediments is important for the global budget of carbon, silicon, and many other elements. Despite the growing recognition of in-situ marine silicate alteration (dissolution and formation), its global significance and controlling factors are still poorly understood. By compiling data from scientific drilling and applying numerical modelling, we investigate the

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)

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

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

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

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

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

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

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,

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

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

Rivers and groundwaters that drain active volcanic areas are characterized by relatively high nutrient concentrations and dissolved loads. The high dissolved load generally results from the fluid–rock interactions with high temperature fluids containing voclanic gases. In this study, the chemistry of spring and river waters from the Kirishima volcanic region (Kyushu, Japan) is analysed to determine

In nature, Cs and Rb follow K, which is a much more abundant but chemically similar element. Data for these elements and their mineral carriers were acquired by the combined ICP-OES/ICP-MS (Inductively Coupled Plasma Optical Emission Spectroscopy/Inductively Coupled Plasma Mass Spectrometry) techniques and quantitative XRD (X-ray diffraction), supplemented by multivariate regression analysis, in order

During terrestrial freshwater discharge to the ocean, the freshwater containing high concentrations of dissolved ferrous iron (Fe2+) come into contact with the saltwater enriched in dissolved oxygen (O2(aq)) within the coastal aquifer, resulting in the oxidation and precipitation of iron (Fe) as Fe oxy(hydr)oxides. The accumulated Fe precipitate forms a low-permeability zone, known as the “iron curtain”

Understanding the processes and contributions of various sources to arc magmas, originating from the mantle wedge, is crucial for unraveling the complex interactions between crust and mantle in subduction zones. Plagioclase with a prolonged crystallization history serves as a key mineral in studying sources of magma and its evolution history. This study presents in-situ trace elements and Pb isotopes

Supra-subduction zone (SSZ) ophiolites, including the Troodos Ophiolite of Cyprus contain magmatic rocks with geochemical compositions indicating that they formed close to a subduction zone. However, the exact tectonic setting in which SSZ ophiolites were formed is debated, although it has been proposed that they represent fragments of fore-arc crust formed during subduction initiation. The sheeted

Plate subduction is pivotal in creating mantle heterogeneity and facilitating deep material recycling. However, the precise origins, input processes, and distribution of recycled components in the upper mantle remain poorly constrained by natural observations. Compared to large ocean basins, marginal sea basins are more likely to preserve detailed information about recycled components due to their

Liquid immiscibility is one of the viable genetic models to generate carbonatites. Experimental studies have demonstrated that lighter Fe isotopes are enriched in carbonatite melts, whereas heavier Fe isotopes preferentially enter silicate melts during liquid immiscibility. However, this observation has not been substantiated by natural samples, and the mechanism behind Fe isotope fractionation during

A population of garnet porphyroblasts, spaced apart between c. 6 mm and 40 mm, in a metapelite of the kyanite zone from the Danba dome was investigated to assess the equilibration length scales of major and trace elements in the intergranular medium during garnet crystallization. Garnet crystallization occurred from ∼525 °C / ∼6.2 kbar to peak conditions of ∼635 °C / ∼6.2–7.7 kbar. Enrichments in the

We present a novel analytical protocol for quantifying and mapping Mn oxidation states in silicates at the nanoscale. Based on X-ray Absorption Near Edge Structure spectra of the Mn L2,3-edges (630–660 eV) acquired thanks to a Scanning transmission X-ray microscope available at various Synchrotron facilities, we calibrate two equations using reference Mn-bearing samples to precisely determine the Mn

The western Eger Rift (Czech Republic) is a currently inactive volcanic rift that is characterised by earthquake swarm activity and degassing of mantle-derived fluids. Free gases and (ultra-) mafic phenocrysts and xenoliths are used to determine the origin and evolution of volatiles in the system and to define the magma reservoir p-T conditions. Isotope compositions of helium in both fluids and minerals

The end-Ordovician mass extinction (LOME), one of the largest biocrises of the Phanerozoic, was linked to a major climatic cooling event, continental glaciation, and oceanic environmental changes. To date, the effect of this biocrisis on marine microbial communities has received scant attention. Here, we generate biomarker records for Upper Ordovician to lower Silurian strata in eastern North America

Nernst partition coefficient data (D) between orthopyroxenes with <5.5 mol% Wollastonite component and melts are compiled and interpreted to generate simple linear equations allowing orthopyroxene/meltD values to be calculated for 48 trace elements. The regression coefficients apply to melts ranging in composition from carbonatite to granite, and use commonly measured and petrologically significant

This work investigates using Brillouin light scattering (BLS) spectroscopy the relationship between chemistry and longitudinal (or pressure) sound-wave propagation on a large dataset of alkaline to sub-alkaline silicate glasses. Results show that the frequency fB of the Brillouin peak decreases with the silica content and the Silica vs. Calcia - Ferrous oxide - Magnesia (SCFM) parameter, while it increases

Mafic dykes intruding continental crustal rocks preserve evidence for the isotopic and geochemical composition of their melt source and hence the chemical makeup of the mantle beneath a continent. We have investigated the geochronology, geochemistry, and Sr–Nd–Os isotopes of recently discovered, Early Permian mafic dyke intrusions in the Alxa Block of the North China Craton to characterize the isotopic