Search Results (146)

Traditional numerical models have been widely employed to simulate the transport of multispecies reactive contaminants in groundwater systems; however, their high computational cost limits their applicability in real-time or large-scale scenarios. Recent advances in artificial intelligence (AI) offer promising alternatives, particularly data-driven machine learning techniques, for accelerating such simulations. This study presents the development of a surrogate model based on artificial neural networks (ANNs) to simulate the transport and decay of interacting multispecies contaminants in groundwater. High-fidelity training datasets are generated through finite difference-based reactive transport simulations across a wide range of environmental and geochemical conditions. The ANN model is trained to learn the complex nonlinear relationships governing the multispecies transport and transformation processes. Model validation reveals that the ANN surrogate accurately reproduces the spatial–temporal concentration profiles of both original and degradation species, capturing key dynamic behaviors with high precision. Notably, the ANN model achieves up to a 100-fold reduction in computational time compared to traditional analytical or semi-analytical solutions. These results highlight the ANN’s potential as an efficient and accurate surrogate modeling tool for groundwater contamination assessment, offering a valuable advancement for decision-making in environmental risk analysis and remediation planning. Full article

The Wangfu Fault Depression (WFD) is located in the southeastern uplift zone of the Songliao Basin and is an important geological site for studying tectonic evolution and volcanic stratigraphy. This study explores the complexity of the structure of the depression and the volcanic stratigraphy. The sedimentary sequence is divided into rift period and post-rift deposition, and the volcanic rocks are mainly concentrated in the Huoshiling Formation. Rhyolite deposits mark the bottom of the Yingcheng Formation. The volcanostratigraphic sequences are described by a detailed analysis of the seismic profiles, cutting samples, core data, geochemical, and well logging data, revealing the interaction between tectonic dynamics and volcanic activity. The volcanic facies are divided into vent breccia, pyroclastic, lava flow, and volcaniclastic sedimentary types, highlighting the diversity of depositional environments. In addition, the study identified key volcanic stratigraphic boundaries, such as eruptive and tectonic unconformities, which illustrate the alternation of intermittent volcanic activity with periods of inactivity and erosion. The study highlights the important role of faults in controlling the distribution and tectonic characteristics of volcanic rocks, and clearly distinguishes the western sag, middle slope, and eastern uplift zones. The chronostratigraphic framework supported by published U-Pb zircon dating elucidates the time course of volcanic and sedimentary processes, with volcanic activity peaking in the Early Cretaceous. Overall, the Wangfu Fault Depression is a dynamic geological entity formed by complex tectonic-volcanic interactions, providing valuable insights into the larger context of basin evolution and stratigraphic complexity. Full article

The Tankou area is a vital production capacity replacement area in the Jianghan oilfield. The recovery of the amount of erosion in Qianjiang Formation and Jinghezhen Formation is significant for studying this area’s tectonic evolution and geothermal history. The target layer, characterised by well-developed plastic materials, intense tectonic deformation, and insufficient well data, fails to meet the applicability criteria of the conventional denudation estimation methods. This study proposes a novel approach based on the structural strain characteristics. The method estimates the stratigraphic denudation by analysing residual formation features and fault characteristics. First, a stress analysis is performed using the fault characteristics, and the change law for the thickness of the target layer is summarised based on the characteristics of the residual strata to recover the amount of erosion in the profile. Second, a grid of the stratigraphic lines in the profiles of the main line and the tie line is used to complete the recovery of the amount of erosion in the plane through interpolation, and the results of the profile recovery are corrected again. Finally, the evolution results of the geological equilibrium method and the stress–strain analysis are compared to analyse the reasonableness of their differences and verify the accuracy of the erosion recovery results. The area of erosion in each layer increases from bottom to top. The amount of denudation in each layer gradually increases from the denudation area near the southern slope to the surrounding area. It converges to 0 at the boundary of the denudation area. The maximum amount of erosion is distributed in the erosion area close to the side of the residual layer with a low dip angle. The specific denudation results are as follows: Qian1 Member + Jinghezhen Formation has a denudation area of 6.3 km² with a maximum denudation thickness of 551 m; Qian2 Member has a denudation area of 2.6 km² with a maximum denudation thickness of 164 m; Qian3 Member has a denudation area of 2.3 km² with a maximum denudation thickness of 215 m; Upper Qian4 Submember has a denudation area of 1.54 km² with a maximum denudation thickness of 191 m; and Lower Qian4 Submember has a denudation area of 1.2 km² with a maximum denudation thickness of 286 m. This method overcomes the conventional denudation restoration approaches’ reliance on well logging and geochemical parameters. Using only seismic interpretation results, it achieves relatively accurate denudation restoration in the study area, thereby providing reliable data for timely analyses of the tectonic evolution, sedimentary facies, and hydrocarbon distribution patterns. In particular, the fault displacement characteristics can be employed to promptly examine how reasonable the results on the amount of denudation between faults are during the denudation restoration process. Full article

The Sanandaj–Sirjan Zone and Zagros Fold–Thrust Belt in Iran host numerous Mediterranean-type karst bauxite deposits; however, their formation mechanisms and critical raw material potential remain ambiguous. This study combines mineralogical and geochemical analyses to explore (1) the formation of authigenic minerals, (2) the role of microbial organic processes in Fe cycling, and (3) the assessment of their critical raw materials potential. Mineralogical analyses of the Late Cretaceous Daresard and Middle–Late Permian Yakshawa bauxites reveal distinct horizons reflecting their genetic conditions: Yakshawa exhibits a vertical weathering sequence (clay-rich base → ferruginous oolites → nodular massive bauxite → bleached cap), while Daresard shows karst-controlled profiles (breccia → oolitic-pisolitic ore → deferrified boehmite). Authigenic illite forms via isochemical reactions involving kaolinite and K-feldspar dissolution. Scanning electron microscopy evidence demonstrates illite replacing kaolinite with burial depth enhancing crystallinity. Diaspore forms through both gibbsite transformation and direct precipitation from aluminum-rich solutions under surface conditions in reducing microbial karst environments, typically associated with pyrite, anatase, and fluorocarbonates under neutral–weakly alkaline conditions. Redox-controlled Fe-Al fractionation governs bauxite horizon development: (1) microbial sulfate reduction facilitates Fe³⁺ → Fe²⁺ reduction under anoxic conditions, forming Fe-rich horizons, while (2) oxidative weathering (↑Eh, ↓moisture) promotes Al-hydroxide/clay enrichment in upper profiles, evidenced by progressive total organic carbon depletion (0.57 → 0.08%). This biotic–abiotic coupling ultimately generates stratified, high-grade bauxite. Finally, both the Yakshawa and Daresard karst bauxite ores are enriched in critical raw materials. It is worth noting that the overall enrichment appears to be mostly driven by the processes that led to the formation of the ores and not by the chemical features of the parent rocks. Divergent bauxitization pathways and early diagenetic processes—controlled by paleoclimatic fluctuations, redox shifts, and organic matter decay—govern critical raw material distributions, unlike typical Mediterranean-type deposits where parent rock composition dominates critical raw material partitioning. Full article

Mineral elements are essential for human health. Our previous study identified distinct clusters of health-related mineral elements in surface soil among different regions and demonstrated an association between these clusters and health profiles in the USA. The present study further explores the relationship between these mineral clusters and mortality from detailed specific types of cancers and cardiovascular diseases by using county-level data from 3080 counties across the USA. Utilizing multivariate regression models with adjustment for socio-demographic and geographical factors, our analysis of county-level data revealed that residents in the regions of ‘infertile’ cluster have higher mortality rates for most types of cancers (18/29) and cardiovascular conditions (4/10) compared with people who live elsewhere. Notably, this relationship is pronounced for several specific leading causes of death such as tracheal, bronchus, lung cancer (regression coefficient (99.5% CIs), 6.29 (4.46, 8.13)), prostate cancer (1.06 (0.53, 1.6)), cerebrovascular disease (3.15 (1.74, 4.55)), and hypertensive heart disease (1.23 (0.23, 2.23)). Our findings highlight the critical role of soil minerals in human health and underscore the need for integrating geochemical data in public health strategies and environmental management policies. Full article

Determining carbon sources and sinks is crucial for understanding the global carbon cycle; however, the enigma of the ‘missing’ sinks remains unresolved. Recent studies have proposed carbonate weathering as a potential carbon sink, underscoring the need to clarify its mechanisms. Previous investigations of carbonate weathering largely relied on soil profiles, which were limited by the rarity of incipient weathering layers. Therefore, we have little knowledge about carbonate incipient weathering processes. To address this gap, spheroidal weathered dolostones were collected from Neoproterozoic Liangjiehe Formation (Nanhua System) in Guizhou, China. The pristine dolostone exhibits δ¹³C values ranging from −5.26 to −3.35‰ and δ¹⁸O values from −13.79 to −12.83‰. These isotopic signatures suggest that the dolostone formed under the high-latitude, cold climatic conditions that were prevalent during the Nanhua Period. Comprehensive petrographic and geochemical analyses of the spheroidal weathered dolostones revealed two distinct stages of incipient weathering. In Stage I, nickel (Ni) and cobalt (Co) contents decrease. The δ¹³C values fluctuate between −7.61 and −2.52‰, while the δ¹⁸O values range from −12.22 to −8.06‰. These observations indicate a weakly acidic microenvironment. In Stage II, there is an enrichment in manganese (Mn), with the δ¹³C values extending from −16.56 to −12.43‰ and the δ¹⁸O values from −8.46 to −7.03‰. These clues suggest a transition to a neutral microenvironment, with the isotopic compositions of carbon and oxygen in the dolomite influenced by atmospheric carbon dioxide (CO₂) and atmospheric precipitation. This study presents a pioneering investigation into the mineralogical and geochemical variations associated with carbonate incipient weathering processes. The variation in C-O isotopes during carbonate incipient weathering may indicate the re-precipitation of HCO₃⁻, suggesting that the carbon sink contribution of carbonate weathering to the global carbon cycle could be overestimated. Full article

The Mamuju region in West Sulawesi, Indonesia, is a High Background Natural Radiation Area (HBNRA) characterized by a significant enrichment of high field strength elements (HFSEs) and rare earth elements (REEs) within its lateritic deposits. This study investigates the geochemical behavior, mineralogical distribution, and enrichment processes of HFSEs and REEs in lateritic profiles of drill cores and surface samples derived from alkaline volcanic rocks. The mineralogy and geochemical content of HFSEs and REEs in the alkaline bedrocks indicate its potential to become a source of lateritic enrichment. An intense lateritic weathering process leads to the residual accumulation of HFSEs and REEs, particularly in B-horizon soils, where clay minerals and Fe–Al oxides are crucial in element precipitation. Moreover, groundwater redox conditions are a key factor for uranium precipitation in the lateritic profile. The findings provide insight into the potential of lateritic weathering as a natural mechanism for HFSE and REE concentration, contributing to the broader understanding of critical metal resources in Indonesia. These insights have implications for sustainable resource exploration and environmental management in areas with high natural radiation exposure. Full article

Creation of alkaline bulk layers from mining waste is economically viable way to prevent the migration of toxic metals down the soil profile and revegetate heavy polluted soils over large areas. We have conducted perennial experiments on the revegetation of industrial barren located near the operating nonferrous smelter in humid subarctic climate. A vermiculite–lizardite material from closed phlogopite mining, containing 10% layered silicates, was used to create the alkaline sorption barrier on the sites with high level of Cu/Ni pollution and wide range of topographic wetness index (TWI). We have revealed the strong effect of TWI on metal accumulation by mineral material with the highest effectiveness for the most wet sites. At the same time, the stable Ca and Mg content over seasons revealed the prolonged material effect for the maintenance of alkalinity and macronutrient supply. Further, we demonstrate the potential of Festuca rubra, Festuca ovina, Achillea millefolium, Deschampsia cespitosa, Dactylis glomerata, Rumex acetosella, Silene suecica, and for the revegetation of mineral material in dry locations. We demonstrated the effectiveness of alkaline geochemical barrier for the accumulation of toxic metals and successful plant growth in a wide range of topographic units. Full article

Regolith-hosted rare-earth element (REE) deposits are some of the most important types of REE deposits. The relationship between Late Paleozoic and Early Mesozoic granite and regolith-hosted REE deposits is still poorly studied. Detailed geochronology, geochemistry, and rare-earth mineralogy analyses of Early Triassic granite in the South China Block were conducted. The geochronological results showed that four representative granite samples yielded formation ages of 245 ± 1 Ma, 244 ± 1 Ma, 244 ± 1 Ma, and 244 ± 2 Ma, respectively. The granites show geochemical affinity to A-type granite. They are characterized by enrichment in Rb, Th, and U, are depleted in Ba, Sr, P, and Ti, and show obvious negative Nb and Ta anomalies. They have high light rare-earth element (LREE) and low heavy rare-earth element (HREE) contents, with obvious negative Eu anomalies. They were derived from the partial melting of a sediment source and underwent intense fractional crystallization during the magma evolution process. They contain a certain number of rare-earth-element-bearing minerals, such as monazite, xenotime, apatite, and zircon. Their REE compositions and mineral associations are similar to those of the parent rocks from typical regolith-hosted REE deposits in South China. The highly weathered horizon at the ridge of the granite weathering crust profile has the highest REE content. A comprehensive analysis indicated that the degree of magma evolution, geomorphology, and weathering are important factors controlling the formation of regolith-hosted REE deposits in the area. Full article

Clays are fundamental raw materials in the ceramics industry due to their plasticity, mineralogical composition, and thermal behavior. This study characterizes four clay samples from Bustos (Portugal), aiming to assess their suitability for ceramic applications through granulometric, geochemical, mineralogical, and technological assays, looking at aspects such as their plasticity and sintering behavior. A textural analysis of the samples revealed distinct granulometric profiles, being dominated by silty–clayey fractions and low amounts of coarse particles, indicating high plasticity potential. Three samples showed an alkaline pH (8.17–8.63), and one an acidic pH (5.11), which can significantly influence the rheology and firing behavior of the ceramic body. Samples had a predominance of phyllosilicate minerals, followed by quartz and magnetite–maghemite, and trace amounts of feldspars, anatase, bassanite, and siderite. In the clay fraction, smectite, illite, and kaolinite were identified. By combining classical analysis techniques with ceramic technology principles, this study contributes to the sustainable development of local ceramic industries, emphasizing the importance of characterizing natural raw materials for industrial applications. The plasticity tests showed strong workability in two samples, which exhibited high values of plasticity and moldability, making them suitable for shaping processes in ceramic production. Also, sintering behavior tests revealed that the same clays exhibited good densification during firing, with relatively low shrinkage. Full article

Magmatic nickel–copper–platinum group element (PGE) deposits hosted in mafic–ultramafic intrusions within volcanic arc systems are highly attractive targets for mineral exploration, yet their genesis remains poorly understood. This study investigates metagabbroic intrusions in the Paleoproterozoic Lynn Lake greenstone belt of the Trans-Hudson Orogen to identify the key factors, in the original gabbros, that control the formation of magmatic Ni-Cu-PGE deposits in volcanic arc systems. By examining the field relationships, geochemical and sulfur and oxygen stable isotope compositions, mineralogy, and structural fabrics, this study aims to explain why some intrusions host mineralization (e.g., Lynn Lake and Fraser Lake intrusions), whereas others remain barren (e.g., Ralph Lake, Cartwright Lake, and Snake Lake intrusions). Although both the fertile and barren gabbroic, likewise original, intrusions exhibit metaluminous, tholeiitic to calc-alkaline affinity with volcanic arc geochemical signatures, they differ significantly in shape, ranging from vertical and tube-like to tabular forms, reflecting distinct geological settings and magma dynamics. The gabbroic rocks of fertile intrusions exhibit erratic trace element profiles, lower (Nb/Th)_N and higher (Cu/Zr)_N ratios, as well as a larger range of δ³⁴S values than those in barren intrusions. Key factors influencing Ni-Cu-PGE mineralization include the degree of partial melting of the mantle, early sulfide segregation, and crustal contamination, particularly from volcanogenic massive sulfide deposits. These processes likely triggered sulfide saturation in the mafic magmas. Geochemical proxies, such as PGE concentrations and sulfur and oxygen stable isotopes, provide critical insights into these controlling factors. The results of this study enhance our understanding of the metallogenic processes responsible for the formation of magmatic Ni-Cu-PGE deposits in the gabbroic intrusions emplaced in an extensional setting due to slab rollback, during the geological evolution of the Lynn Lake greenstone belt, offering valuable guidance for mineral exploration efforts. Full article

Soil temperature, a key factor in subsurface geochemical processes, is influenced by environmental and geological dynamics. This study analyzed hourly soil temperature variations at depths of 10 to 100 cm near the Sakurajima volcano, alongside concurrent ambient temperature measurements. By applying temperature models and statistical methods, we characterized both seasonal and short-term thermal dynamics, including soil-atmosphere thermal coupling. Our findings revealed a depth-dependent thermal diffusivity, establishing distinct thermal regimes within the soil profile. The soil’s strong thermal buffering capacity, evidenced by increasing amplitude attenuation and temporal lag with depth, allowed us to identify optimal instrument placement depths (80–100 cm) for minimal diurnal temperature influence. We also quantified the relationship between ambient temperature fluctuations and soil thermal response at various depths, as well as the impact of these temperature variations on soil permeability. These results enhance our understanding of subsurface thermal behaviour in volcanic environments and offer practical guidance for environmental monitoring and geohazard studies. Full article

The opening of the Qiongzhou Strait during the Holocene was a significant geological event in the Beibu Gulf, profoundly influencing sediment provenance and ocean circulation systems. Due to the scarcity of geological records documenting this event, the understanding of regional Holocene sedimentary evolution has been constrained. To investigate the impact of this event on sediment provenance and ocean currents in the Beibu Gulf, geochemical analyses were conducted on sediment core SO-31 retrieved from the South China Sea. The sediments in core SO-31 were stratigraphically divided into three units based on vertical geochemical profiles, reflecting changes in sea level and shifts in sediment provenance within the study area. The Th/Cr vs. Th/Sc scatter plot for core SO-31 indicate that sedimentary materials primarily originated from the Red River during 11,400–7700 a BP, and a significant change in provenance occurred in the study region around 7700 a BP, characterized by increased contributions from the Qiongzhou Strait and decreased contributions from the Red River. This suggests that the opening of the Qiongzhou Strait significantly influenced the sediment supply to the central Beibu Gulf around 7700 a BP. These findings provide critical geochemical evidence for studying the Qiongzhou Strait opening event and enhance our understanding of Holocene sedimentary evolution and “source–sink” transitions in the Beibu Gulf. Full article

Archaeal lipids, defining a primordial life domain alongside Bacteria and Eukarya, are distinguished by their unique glycerol-1-phosphate backbone and ether-linked isoprenoid chains. Serving as critical geochemical biomarkers, archaeal lipids like glycerol dialkyl glycerol tetraethers (GDGTs) underpin paleoclimate proxies, while their phylum-specific distributions illuminate phylogenetic divergence. Despite the maturity of Mass Spectrometry-based quantitative biomarkers—predominantly those with established structures—becoming well-established in geochemical research, systematic investigation of archaeal lipids as natural products has notably lagged. This deficit manifests across three key dimensions: (1) Extraction methodology lacks universal protocols adapted to diverse archaeal taxa and sample matrices. While comparative studies exist, theoretical frameworks guiding method selection remain underexplored. (2) Purification challenges persist due to the unique structures and complex isomerization profiles of archaeal lipids, hindering standardized separation protocols. (3) Most critically, structural characterization predominantly depends on decades-old foundational studies. However, the existing reviews prioritize chemical structural, biosynthetic, and applied aspects of archaeal lipids over analytical workflows. This review addresses this gap by adopting a natural product chemistry perspective, integrating three key aspects: (1) the clarification of applicable objects, scopes, and methodological mechanisms of various extraction technologies for archaeal lipids, encompassing both cultured and environmental samples; (2) the elucidation of separation principles underlying polar-gradient lipid fractionation processes, leveraging advanced chromatographic technologies; (3) the detailed exploration of applications for NMR in resolving complex lipid structures, with specialized emphasis on determining the stereochemical configuration. By synthesizing six decades of methodological evolution, we establish a comprehensive analytical framework, from lipids extraction to structural identification. This integrated approach constructs a systematic methodological paradigm for archaeal lipid analysis, bridging theoretical principles with practical implementation. Full article

During the deposition of the Middle–Upper Triassic Yanchang Formation, the southern margin of the Ordos Basin (OB) serves as a critical area for investigating the tectonic interactions between the North China Block (NCB) and Qinling Orogenic Belt (QOB). The provenance record of this sedimentary succession can be utilized to trace basin–mountain interactions using petrological, geochemical, and zircon age geochronological studies. We analyzed lithic fragments, geochemistry, and detrital zircon U–Pb ages of samples from the Xunyi Sanshuihe field profile, Weibei Uplift. Discrimination diagrams of major and trace elements revealed provenances and tectonic-sedimentary settings. Middle–Upper Triassic sandstones comprise quartz, feldspar, and lithic fragments. Their compositions are plotted within recycled orogenic and magmatic arc provenance fields. Multiple element diagrams reveal a felsic igneous rock provenance. Detrital zircon age spectra display four prominent age groups, which are ca. 240–270, 410–450, 1800–2200, and 2400–2600 Ma, and one minor age group, that is, 870–1197 Ma in the Late Triassic sample. We conclude that the provenance of the Yanchang Formation changed significantly during the Middle–Late Triassic. The Late Triassic sediments were mainly QOB-derived, and the basement was from the NCB. The pre-Triassic strata and Longmen pluton in the southwest of OB were the provenance of Middle Triassic sediments. The QOB suffered rapid uplift and denudation, resulting in rapid deposition and deep-water deposition in the southern OB, which provides excellent conditions for the high-quality oil shale of Ch 7. Full article