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Identifies core journals in environmental geology and explores facets of interdisciplinarity to consider the visibility of this field to collection-development librarians. Intercitation analysis of citing and cited patterns in 1995 articles revealed the journal network of environmental geology. Titles clustered into three categories: Engineering/Materials; Geochemical; and Water/Soil. (Author/AEF)

In this paper, sedimentological and geochemical data from six cores are presented and discussed in order to better understand the Holocene palaeoenvironmental evolution of the coastal plains of the Pecora and Cornia Rivers (southern Tuscany, Italy). Overall, the stratigraphies show a general upward trend in the evolution of the sedimentary succession of lagoonal environments (low Zr/Rb, high EC values) connected or partially connected to the sea (low EC values), to a seaward progradation of marshy-swampy environments (Mn/Ti, high TOC values) and finally to continental environments with the progradation of distal alluvial plains (high Zr/Rb, low EC values) influenced by runoff phenomena or local water stagnation. This trend is closely related to the increasing input of sediments from inland due to soil erosion processes and, especially in the last two centuries, land reclamation works. In the Cornia coastal plain, the chronologies indicate that lagoonal environments were already present before ca. 8.2ka BC and started receding seaward at around 3.7ka BC. On the other hand, chronologies from ca. 0.5ka BC to ca. 0.6ka AD point to a persistence of lagoonal environments only in areas very close to those already identified as such in historical cartography. In the Pecora coastal plain, the chronologies show that the lagoon environments had already disappeared before ca. 3.3ka BC, whilst the peripheral environments were characterised by abundant vegetation. The latter gradually degraded in favour of the development of shallow to very deep, unvegetated marshlands, which persisted until ca. 1ka AD. [ABSTRACT FROM AUTHOR]

The Chang 9 oil layer deposits within Ansai District, Ordos Basin, yield considerable reserves of crude oil, yet their source remains ambiguous. This research endeavor was designed to characterize the Chang 9 crude oil and the Chang 7 and Chang 9 source rocks (SRs) of the Yan‐Chang Formation via organic geochemical analysis. The results indicate that the Chang 9 crude oil exhibits a Pr/Ph ratio of 0.84–2.29 and Ga/C30H less than 0.1, implying formed in a weak reduction to weak oxidation freshwater environment. The regular sterane C27‐C28‐C29 configuration assumes an inversed "L" type, reflecting mixed sources and dominant terrestrial plant input. Ratios such as C2920S/(20S + 20R) (0.54–0.6) and C29ββ/(ββ + αα) (0.44–0.58) indicate a mature oil stage. The depositional environment of the C7 and C9 SRs is similar, with weak oxidation to reduction conditions, and consists mainly of Type I and II organics, with a relatively higher maturity of the C9 SRs. A difference in C19/C23TT and C30D/C30H was found between the C7 and C9 SRs. The results show that the C9 crude oils have a similar C19/C23TT with the C9 SRs and similar diahopanes distribution with Class II SRs (C7 and part of the C9 SRs). Thus, the C9 crude oils most likely originate from the C9 SR mixed with the C7 SRs. [ABSTRACT FROM AUTHOR]

ABSTRACT The study investigated 50 Permian coals from the Singrauli Coalfields in the Son Valley Basin, India, using advanced petro‐geochemical techniques to assess their source rock properties, energy and utilisation potential and to reconstruct the paleodepositional environment. Petrological analysis indicated vitrinite reflectance values between 0.39% and 0.49%, classifying the Singrauli coals as sub‐bituminous to high volatile bituminous rank and indicating a thermally immature state. The results of geochemical analysis (volatile matter: 36.8%–46.5% and Tmax: 420°C–425°C) further support the above contention. High carbon content (average 77.89%), low sulphur content (average 0.46%) and varying nitrogen and oxygen levels in studied coal enhance its environmental suitability. The hydrogen index (HI: 163–279 mg HC/g TOC) values suggest a predominance of type‐III kerogen with mixed type‐II–III kerogen, further supported by petrographic data. Moreover, geochemical and petrographic data suggested the suitability of Singrauli coals for gasification. The high total organic carbon (TOC ≥ 38 wt%) indicated admirable potential as a source rock for hydrocarbon generation, particularly within the gas‐source rock zone, highlighting their suitability for energy production. Petrographic indices indicated a wet forest swamp origin with a telmatic source and bog region under ombrotrophic to mesotrophic hydrological circumstances. The association of macerals and total sulphur content further supported the conclusion of a freshwater environment during peat deposition. [ABSTRACT FROM AUTHOR]

Invasive zebra and quagga (dreissenid) mussels have disrupted nutrient cycling and benthic macrofauna communities in the Laurentian Great Lakes and other invaded ecosystems. Dreissenids are now the dominant benthic macroinvertebrate in the Great Lakes, replacing the formerly dominant native bioturbating amphipod Diporeia spp. Dreissenids and Diporeia interact with their environment in fundamentally different ways, and the consequences of this functional shift in benthic community structure on benthic–pelagic coupling are not well understood, particularly in unproductive offshore lake regions. To determine how functional biology and benthic community structure impact sediment mixing and biogeochemistry in low particulate organic matter (POM) lake regions, we conducted a 6‐week sediment microcosm experiment with dreissenids, Diporeia and oligochaete worms—the second most common Great Lakes benthic macroinvertebrate. We found that sediment mixing rate and depth varied significantly among the taxa. Diporeia mixed sediment the deepest and strongest, followed by oligochaetes, while dreissenids did not appreciably mix sediment. Despite these differences, we found no significant variations among treatments in sediment oxygen penetration depth, sediment respiration (oxygen uptake) or nutrient dynamics. Our results suggest that dreissenids mix sediment less than native Great Lakes taxa, but that differential mixing rates may not measurably affect nutrient and oxygen dynamics in low‐POM sediments. Therefore, mussel effects in these areas may be manifested more through direct mechanisms rather than via altered sediment geochemistry. [ABSTRACT FROM AUTHOR]

Depleted shergottites record unique information about the primary composition and differentiation of the mantle of Mars. Their petrology, geochemistry, and cosmic ray exposure and crystallization ages suggest that most of them were excavated by a single young impact in the Amazonian‐aged lava flows of the Tharsis and Elysium volcanic provinces. However, the difficulties of deriving consistent model ages for individual craters and inadequate evaluation of 3‐7 km craters capable of ejecting martian meteorites have not been settled. Here we perform detailed geological investigations and crater statistics in patches of impact melt deposits for potential source craters of depleted shergottites with D > 3 km, especially those in the Tharsis and Elysium volcanic provinces. By excluding the effect of heterogeneous textures across ejecta deposits, which hinder straightforward extraction of superposed production populations, our systematically updated model ages reveal that Chakpar crater at the northern flank of Ascraeus Mons is the best‐fit candidate. The local context of this crater permits establishing a link between the meteorites and specific lava flows. The long‐lived volcanic center here may experience an eruption and/or local deposition hiatus for about 1.8 billion years, and abundant subsurface water existed when the impact occurred at about 1.1 million years. [ABSTRACT FROM AUTHOR]

Research on the geological process of the Xing'an -- Mongolia Orogenic Belt has attracted the attention of scholars both domestically and internationally. Its genesis and tectonic location may help revealing the geological processes asscoaited with the evolution of the Xing'an -- Mongolia Orogenic Belt. This study focuses on the development of the Permian granitic complex in Jielin Ranch, and we conduct systematic geological, petrographic, zircon U-Pb chronology, Hf isotope, and geochemical tracing of rock elements for evidence. The results show that the granitic complex is mainly composed of monzogranite and syenogranite, which obtained zircon U-Pb ages of 291.1 ± 1.1 Ma and 260.8 ± 1.1 Ma, respectively. The monzogranite and syenogranite are all acidic and aluminum rich rocks, and the monzogranite is a potassium rich, high potassium calcium alkaline rock series with relatively low REE content, high degree of fractionation, and insignificant europium anomalies, enriched with LILE (Rb, Th, U, K), deficient elements such as Ba, Sr, Nb, Ti, and P, εHf(t) values are from +4.1 to +7.0 (TDM2=1130-920 Ma). Geochemistry shows that the monzogranite belongs to high fractionation of I-type granite, which formed in a subduction-compressional or extension tectonic environment, and Middle Neoproterozoic lower crust rocks as the major source material of magma. The syenogranite is a potassium high potassium transitional rock series with a high rare earth content (214 x 10-6~325 x 10-6), low LREE/HREE (2.54-6.41), δEu (0.04-0.15) and the typical "four component effect" fractionation mode is enriched in large ion lithophilic elements such as Rb, Th, K, and strongly depleted in elements such as Ba, Sr, Nb, Ta, Ti, P, εHf(t) values are from +4.2 to +8.6 (TDM2=738-1228 Ma), suggesting the characteristics of an "A2 type" granite. The magma originated from partial melting of the lower crust of the Middle and Neoproterozoic with the participation of mantle derived melts, and was formed in a back-arc extensional environment. This suggests that the study area experienced a subduction-compressional or extension tectonic environment during the early Permian and a brief backarc extension process in the late Permian. [ABSTRACT FROM AUTHOR]

The Tianshan Orogenic Belt underwent a series of complex tectonic changes from the Late Palaeozoic to the Cenozoic, providing key insights into the evolution of the Central Asian Orogenic Belt (CAOB). The continuous Permo-Triassic sedimentary records of the Turpan Basin are among the best archives of the tectonic evolution of the Tianshan Orogenic Belt. However, the evolution of the Turpan Basin during this period is poorly understood. Using detrital zircon U-Pb chronology and geochemistry, we reconstructed the source-to-sink system changes and the basinal tectonic evolution in the Permo-Triassic, thus providing new evidence of its tectonic evolution. Our results show that the Early-Middle Permian source-to-sink systems of the Turpan Basin were mainly proximal and constrained by horst and graben landforms due to internal extension formed in the back-arc setting during accretionary orogenesis in Central Asia. In the Late Permian-Early Triassic, exotic sources, including the North Tianshan and Yili Block-Central Tianshan, dominated the source-to-sink system, which suggests that rifts were infilled and expanded across the entire thermal sag basin. In the Middle-Late Triassic, the sediment sources diversified, with external and internal provenances revealing that a foreland basin formed with thrusting at the southern margin, and the intraplate-associated Bogda forebulge experienced initial uplift, signifying that the CAOB gradually changed from an accretionary to an extrusive orogeny. The three evolutionary episodes of the Turpan Basin implicated the long-lasting effect of the orogenic process from the final closure of Palaeo-Asian Ocean to the following build-up of the CAOB. [ABSTRACT FROM AUTHOR]

Antecedent hydrological conditions are recorded through the evolution of dissolved lithium isotope signatures (δ7 ${\delta }^{7}$Li) by juxtaposing two storm events in an upland watershed subject to a Mediterranean climate. Discharge and δ7 ${\delta }^{7}$Li are negatively correlated in both events, but mean δ7 ${\delta }^{7}$Li ratios and associated ranges of variation are distinct between them. We apply a previously developed reactive transport model (RTM) for the site to these event‐scale flow perturbations, but observed shifts in stream δ7 ${\delta }^{7}$Li are not reproduced. To reconcile the stability of the subsurface solute weathering profile with our observations of dynamic stream δ7 ${\delta }^{7}$Li signatures, we couple the RTM to a distribution of fluid transit times that evolve based on storm hydrographs. The approach guides appropriate flux‐weighting of fluid from the RTM over a range of flow path lengths, or equivalently fluid residence times. This flux‐weighted RTM approach accurately reproduces dynamic storm δ7 ${\delta }^{7}$Li‐discharge patterns distinguished by the antecedent conditions of the watershed. Plain Language Summary: Storm events often cause characteristic shifts in stream solute chemistry. Interpreting these signals offers insight into the water‐rock interactions occurring within watersheds. Here, we use lithium stable isotopes and reactive transport modeling to relate how long water spends in a catchment, or how deep water infiltrates through a catchment, to the extent of chemical weathering. We show that the first significant storm after a dry season exports more chemically evolved water, while a wet season storm releases less evolved, shallower, and younger water. Our results indicate that stream flow δ7 ${\delta }^{7}$Li in small watersheds offers a sensitive record of hydrological conditions prior to the storm, reflecting subtle shifts in the efficiency of the Critical Zone to generate, transport, and ultimately export solutes. Key Points: Stream lithium stable isotope ratios (δ7Li) recorded at high frequency over storm events are sensitive to antecedent conditionsA reactive transport model cannot produce observed shifts in stream chemistry through variations in flow rate aloneFlux‐weighting of model fluid outputs based on time‐varying fluid transit time distributions describes stream δ7Li over storm hydrographs [ABSTRACT FROM AUTHOR]

The El Salvador plutonic complex is a 9.2 km2 circular body within the Sierra de Tamaulipas, part of the Eastern Mexican Alkaline Province (EMAP). Three alkaline magmatic suites were identified from El Salvador from the geochemical analysis of 20 samples. Suite A (SiO2 = 58.3–65.3 wt.%) is ferroan (Fe* = 0.761–0.873) and alkalic (MALI = 4.83–9.89). In contrast, Suites B (SiO2 = 52.5–60.8 wt.%; Fe* = 0.680–0.756) and C (SiO2 = 50.5–67.1 wt.%; Fe* = 0.616–0.749) are magnesian. Suite B is alkali-calcic (MALI = -2.18–4.64), while Suite C is alkalic (MALI = 4.48–8.59). All suites display arc-related signatures. U-Pb and fission-track geochronology data reveal two uplift episodes during the cooling history of Suite A. One in the Late Eocene was based on U-Pb zircon (38.42 ± 0.21 Ma) and titanite ages (35.54 ± 3.77 Ma). The other was during the Oligocene from U-Pb apatite (29.9 ± 6.54 Ma) and fission-track titanite (30.2 ± 5.53 Ma) and apatite ages (32.7 ± 7.06 Ma). Integrating the arc-related signatures of El Salvador rocks with the well-documented Palaeogene arc magmatism of the Sierra Madre del Sur, we propose that the mantle beneath the EMAP experienced metasomatism during the Early Permian (and possibly the Early Jurassic) but not after the Late Cretaceous, ruling out Cenozoic slab subduction in eastern Mexico. In the absence of a slab to explain the El Salvador magmatism, we suggest a long-lasting, widespread mantle upwelling beneath Mexico's northern half in response to the Farallon slab's break-up. Under this context, the westward drift of the North American plate led to the Mexican Foreland Basin lithosphere reaching this massive mantle upwelling in late Eocene times to produce the EMAP magmatism. [ABSTRACT FROM AUTHOR]

The Araba and Naqus formations in Ras Milan, Sinai, constitute part of the major continuous Paleozoic clastic belt stretching across northern Gondwana. They are sandstone-dominated successions, resting on Precambrian granitic basement, with lowermost thin basal polymictic conglomerate deposits (1–2 m), marking the unconformity. The Araba Formation section is composed mainly of varicoloured violet to reddish brown, fine to coarse-grained laminated and planner and overturned cross-bedded sandstones, while the overlying Naqus Formation is characterized by chaotically distributed poorly sorted quartz pebbles to cobbles within a moderately-sorted coarse- to medium-grained quartz arenite and by abundance and variety of large-scale tabular and trough cross bedding. Modal QFL classification of Araba and Naqus formation sandstones revealed that they are merely quartzose sandstones (quartz arenites). Geochemistry of the succession shows extremely wide compositional ranges for almost all major elements, but the Araba Formation is relatively enriched in SiO2, TiO2, Fe2O3*, Na2O, P2O5, and depleted in Al2O3, MgO, CaO and K2O relative to Naqus Formation. Only the Araba Formation samples are depleted in the transition elements Ni, Cr and Co and oppositely possess extreme enrichment in the HFSEs (i.e. Zr, Hf, Y, Nb, Ta, Th, U), whereas both formations show variable depletion in the LILE Rb, K and Ba, and excessive REE abundances relative to the PAAS and UCC, and LREE-enriched patterns with marked negative Eu anomalies. The provenance of the Naqus and Araba formations could be an earlier felsic magmatic source, which has undergone extensive sedimentary recycling. They possess high compositional maturity and were subjected to intensive to moderate weathering during humid climatic conditions. Passive margin tectonic setting is implied which denotes the derivation of Araba and Naqus formation siliciclastics from stable continental regions or plate interiors and deposition in intracratonic basins. [ABSTRACT FROM AUTHOR]

A combined study of whole-rock geochemical and Sr-Nd isotopic data, and zircon U-Pb geochronological and Hf isotopes has been carried out for several Neoproterozoic intrusions, including the Lung Thang, Posen and Sin Quyen in the Phan Si Pan Zone, northwest Vietnam to constrain their age, petrogenesis and tectonic implications. The Lung Thang and Posen intrusions, mainly composed of granodiorite, were formed at 803–777 Ma and are characterized by moderate SiO2 (64.43–66.65 wt.%), and K2O (4.05–4.89 wt.%), with A/CNK and A/NK values of (0.94–1.03) and (1.72–2.11), respectively. They have negative whole-rock εNd(t) (−6.16 to −3.73) and zircon εHf(t) values (−7.9 to −4.1), which suggest that the Lung Thang and Posen intrusions were generated by partial melting of ancient, K-rich crustal rocks. The Sin Quyen intrusion, occurring as dykes, is composed of monzodiorite and was emplaced at 742 ± 3 Ma. The Sin Quyen intrusion has high alkalies (K2O+Na2O = 7.42–7.47 wt.%), and low MgO (<1.31 wt.%) and Ni (6.55–6.93 ppm), with A/CNK and A/NK values of (0.67–0.68) and (1.64–1.68), respectively. Their whole-rock εNd(t) and zircon εHf(t) values are −6.15 to −5.92 and −5.8 to + 8, respectively. These geochemical characteristics suggest that the Sin Quyen intrusion was produced by the partial melting of ancient crustal sources mingled with mantle-derived components. Geochemically, the Lung Thang, Posen and Sin Quyen intrusions are medium- to high-K, calc-alkaline in nature and show enrichment in LILE (Th, U, K, Rb) and LREE, and strong negative anomalies of Nb, Ta, and Ti. Such geochemical characteristics suggest that they formed in a subduction-related tectonic environment. The geochronological and geochemical correlation of these intrusions with those along the southwestern margin of the Yangtze Block in South China suggests that the Phan Si Pan zone in northwestern Vietnam is a constituent of the SW Yangtze Block. Additionally, these intrusions show a significant correlation with other contemporaneous magmatic rocks in the northeast Indochina Block, Lhasa Block, the northwestern margin of Greater India as well as those in Seychelles and northern Madagascar. This correlation suggests a similar history and synchronous episode of crustal growth/recycling in an Andean-type arc system along the western and northern margin of the Rodinia supercontinent during the Neoproterozoic. [ABSTRACT FROM AUTHOR]

Background: The Andean Altiplano hosts a repertoire of high-altitude lakes with harsh conditions for life. These lakes are undergoing a process of desiccation caused by the current climate, leaving terraces exposed to extreme atmospheric conditions and serving as analogs to Martian paleolake basins. Microbiomes in Altiplano lake terraces have been poorly studied, enclosing uncultured lineages and a great opportunity to understand environmental adaptation and the limits of life on Earth. Here we examine the microbial diversity and function in ancient sediments (10.3–11 kyr BP (before present)) from a terrace profile of Laguna Lejía, a sulfur- and metal/metalloid-rich saline lake in the Chilean Altiplano. We also evaluate the physical and chemical changes of the lake over time by studying the mineralogy and geochemistry of the terrace profile. Results: The mineralogy and geochemistry of the terrace profile revealed large water level fluctuations in the lake, scarcity of organic carbon, and high concentration of SO42--S, Na, Cl and Mg. Lipid biomarker analysis indicated the presence of aquatic/terrestrial plant remnants preserved in the ancient sediments, and genome-resolved metagenomics unveiled a diverse prokaryotic community with still active microorganisms based on in silico growth predictions. We reconstructed 591 bacterial and archaeal metagenome-assembled genomes (MAGs), of which 98.8% belonged to previously unreported species. The most abundant and widespread metabolisms among MAGs were the reduction and oxidation of S, N, As, and halogenated compounds, as well as aerobic CO oxidation, possibly as a key metabolic trait in the organic carbon-depleted sediments. The broad redox and CO2 fixation pathways among phylogenetically distant bacteria and archaea extended the knowledge of metabolic capacities to previously unknown taxa. For instance, we identified genomic potential for dissimilatory sulfate reduction in Bacteroidota and α- and γ-Proteobacteria, predicted an enzyme for ammonia oxidation in a novel Actinobacteriota, and predicted enzymes of the Calvin–Benson–Bassham cycle in Planctomycetota, Gemmatimonadota, and Nanoarchaeota. Conclusions: The high number of novel bacterial and archaeal MAGs in the Laguna Lejía indicates the wide prokaryotic diversity discovered. In addition, the detection of genes in unexpected taxonomic groups has significant implications for the expansion of microorganisms involved in the biogeochemical cycles of carbon, nitrogen, and sulfur. EPcqnK6xUD66cr6MUL2q3U Video Abstract [ABSTRACT FROM AUTHOR]

The 72‐foot sailing yacht Eugen Seibold is a new research platform for contamination‐free sampling of the water column and atmosphere for biological, chemical, and physical properties, and the exchange processes between the two realms. Ultimate goal of the project is a better understanding of the modern and past ocean and climate. Operations started in 2019 in the Northeast Atlantic, and will focus on the Tropical Eastern Pacific from 2023 until 2025. Laboratories for air and seawater analyses are equipped with down‐sized and automated state‐of‐the‐art technology for a comprehensive description of the marine carbon system including CO2 concentration in the air and sea surface, pH, macro‐, and micro‐nutrient concentration (e.g., Fe, Cd), trace metals, and calcareous plankton. Air samples are obtained from ca. 13 m above sea surface and analyzed for particles (incl. black carbon and aerosols) and greenhouse gases. Plankton nets and seawater probes are deployed over the custom‐made A‐frame at the stern of the boat. Near Real‐Time Transfer of underway data via satellite connection allows dynamic expedition planning to maximize gain of information. Data and samples are analyzed in collaboration with the international expert research community. Quality controlled data are published for open access. The entire suite of data facilitates refined proxy calibration of paleoceanographic and paleoclimate archives at high temporal and spatial resolution in relation to seawater and atmospheric parameters. Plain Language Summary: The new research sailing yacht Eugen Seibold (ES) enables clean, contamination‐free sampling of air and seawater to better understand the interactions between ocean and climate. For example, the oceans remove increasingly less carbon dioxide (CO2) from the atmosphere the more saturated they are with CO2 (ocean acidification). However, a detailed systematic understanding of air‐sea exchange processes remains to be developed. We analyze air and seawater as well as the exchange of greenhouse gases and other substances such as aerosols and soot (black carbon) between air and seawater at high resolution using modern materials and technologies. Scaled‐down, energy‐efficient, and automated probes developed over the past decade are being used to measure around 50 different characteristics of the marine environment. The work deck at the stern of the boat allows the use of custom‐made water samplers and plankton nets to study the ocean to below 1,000 m depth. In addition, the new data enables a better understanding of past ocean archives, such as the marine plankton accumulated in seafloor sediments, to reconstruct past climate changes. From 2019 to 2022, the S/Y ES sailed in the eastern North Atlantic and will operate in the tropical eastern Pacific until 2025. Key Points: New research platform for contamination‐free sampling of the water column and atmosphere of biological, chemical, and physical propertiesComprehensive marine geochemical analyzes including carbon (e.g., CO2) in air and sea surfaceProxy calibration of paleoclimate archives at high temporal and spatial resolution in relation to seawater and atmospheric parameters [ABSTRACT FROM AUTHOR]

The global demand for lithium is steadily increasing, driving an increased focus on exploration efforts worldwide. Lithium, a crucial metal for lithium-ion batteries (LIBs) used in renewable energy technologies, is vital in the global drive to reduce carbon emissions. India’s ambitions to become a manufacturing hub for LIBs and achieve 100% electric vehicle (EV) sales by 2030 require significant quantities of lithium. However, challenges due to limited domestic reserves within the country, prompting efforts to define new exploration targets and develop existing lithium occurrences. Recent discoveries in northern Jammu and Kashmir and southern Karnataka highlight promising lithium deposits. This study focuses on India’s lithium exploration within pegmatite belts across various cratonic blocks, identifying significant potential for lithium exploration and mining. Notably, spodumene-rich pegmatites are found in Karnataka’s Dharwar Craton, while lepidolite-rich pegmatites exist in Rajasthan’s Aravalli-Delhi Fold Belt and the Madhya Pradesh-Chhattisgarh region. Regions like Bihar-Jharkhand, Maharashtra, Odisha, and Assam-Meghalaya also exhibit promise for lithium exploration. These findings emphasize the diverse lithological settings where lithium exploration can be strategically pursued in India. This study recommends adopting modern exploration techniques and developing cost-effective extraction technologies to advance India’s lithium exploration efforts. These initiatives are crucial in meeting the escalating demand for lithium and advancing India’s clean energy objectives in the transition to renewable energy sources. [ABSTRACT FROM AUTHOR]

Environmental reference conditions (RC) and historical trends are crucial for assessing the degree of freshwater impact and formulating restoration measures. This is particularly relevant for freshwater systems used as potable water sources. Using sediments from the Carlos Maggiolo reservoir (Minas, Uruguay), located in a watershed with a mining history, this study aimed to (1) establish metal (As, Cr, Cu, Ni, Pb, and Zn) RC using a predicted interval (PI) chemometric technique; (2) evaluate metal enrichment and toxicity over time and space; and (3) assess environmental changes examining geochemical proxies. Surface sediments from 29 stations were used to establish RC and a core from the dam area was sampled to infer past conditions. The sediments were submitted to partial digestion and analyzed by inductively coupled plasma optical emission spectrometry- ICP-OES. Enrichment factor (EF) calculated using both PI and bottom core values did not show significant differences over time. Over space and time, most metals primarily originated from natural sources (EF < 2). The PI in mg/kg was Cr: 23.74–37.32; Cu: 25.75–48.99; Ni: 16.29–25.55; Pb: 7.63–13.75; and Zn: 94.34–174.80. A stratigraphically constrained cluster analysis corroborated by a permutational multivariate analysis of variance categorized the reservoir into two zones: Zone I, before reservoir operation to ~ 1996, and Zone II from ~ 1997 to 2017. The average concentrations of the main metals of toxicological interest in zones I and II, respectively, were as follows: Cr 37.60 ± 1.59, 34.54 ± 1.49 mg/kg; Cu 49.76 ± 2.84, 44.55 ± 2.70 mg/kg; Ni 24.11 ± 0.67, 22.53 ± 1.22 mg/kg; Pb 12.40 ± 0.63, 13.52 ± 0.82 mg/kg; Zn 99.25 ± 3.12, 93.86 ± 4.42 mg/kg; Mn 1160.56 ± 68.88, 1441.61 ± 83.55 mg/kg; and P 1243.21 ± 271.56, 1128.42 ± 183.10 mg/kg. According to a principal component analysis, the period preceding reservoir operation until ~ 1985 was linked to mining activities and application of Cu2SO4, and the period from 1985s to 2000 was influenced by C and P concentrations due to increasing agricultural and afforestation activities in the watershed that consume P fertilizers. The most recent period, from 2000 to ~ 2017, was characterized by an increase in sedimentation rates mainly associated with erosion, particularly in the agricultural areas. This subsequent soil loss in the watershed could compromise the reservoir's useful life. This study contributes to a better understanding of metal geochemistry in subtropical reservoirs and aids in formulating effective recovery and restoration measures. [ABSTRACT FROM AUTHOR]

Abstract\nKEY POINTSStudies of lithogeochemical dispersion haloes of rare metal pegmatites, particularly those of economic interest, are known to display strong development of haloes of rare alkali elements (Li–Rb–Cs), in particular lithium, into country rocks. The use of these haloes in exploration for pegmatites has had apparently little application in an Australian context, where it has the potential to assist exploration undercover by expanding the known ‘footprint’ of these mineral systems. Dispersion haloes have two parts: proximal (typically of centimetres to metres thickness), characterised by visible changes to mineralogy relating to metasomatism, and distal, where there are typically cryptic geochemical changes, but no changes in host mineralogy. Collation of global data have shown that the lithogeochemical haloes of large rare metal pegmatites can extend laterally at least 200 m, with a few localities giving indications extending several kilometres along strike. Lithium displays the largest haloes, with Rb and Cs typically being less extensive; other elements are mostly localised close to the pegmatite wallrock interface. These haloes are more extensive in mafic host rocks than other host-rock types. Mafic host rocks also provide the best geochemical contrast for rare alkali elements. Of the 22 datasets reviewed here, many are simply ‘proof of concept’ studies based on single sample lines and may not have had their outer limits defined. The actual distribution of these haloes is likely to be controlled by anisotropies that control host-rock permeability in the host units, with fluids emanating from the rare metal pegmatites being commonly channelled into structures or exploiting foliation or bedding. Regional-scale structures are likely to control kilometre-scale haloes. Sheet silicates and amphiboles are the most important hosts for these elements, which consequently accumulate in units or structures rich in these minerals. The actual distributions of these elements are, in most cases, likely to be irregular and complex anomalies of varying three-dimensional shapes, and thus ‘vectoring’ based on systematic changes in concentration away from a source should be treated with caution. It is important to note that given anomaly types do not indicate the presence of particular minerals, such as spodumene. The presence of these haloes in Australian Archean cratons is supported by dispersion haloes in saprolite and saprock units in deep weathering profiles and is potentially applicable to lag sampling over near fresh or unweathered host-rock units in exposed terranes.Lithogeochemical haloes of Li–Rb–Cs represent a simple exploration tool that can be readily integrated into exploration workflows by assay of host rock units in proximity to LCT granitic pegmatites.Haloes extend laterally at least 200 m and show indications of kilometre-scale anomalies relating to structurally controlled fluid flow.Haloes are spatially more extensive and show greater geochemical contrast with backgrounds, in mafic host units.These rare alkali haloes may persist into weathered host-rock units such as saprolite in regolith profiles. [ABSTRACT FROM AUTHOR]

The Central lapetus Magmatic Province (CIMP) is a large igneous province (LIP) emplaced in the Baltican and Laurentian paleocontinents that marks the onset of the Caledonian Wilson Cycle. Paleozoic magmatism of the CIMP is preserved in both northeastern America and northern Europe. This study investigates rocks belonging to the hyper-extended margin of Baltica currently found in the Seve Nappe Complex of the Scandinavian Caledonides. Specifically, U-Pb zircon geochronology and whole-rock geochemistry are applied to a migmatitic variety of the Vierrucohkka amphibolite of the Marma Terrane, to the Aurek gabbro, and amphibolite of the Aurek Assemblage exposed in the Seve Nappe Complex in the Kebnekaise region, northern Swedish Caledonides. U-Pb zircon geochronology yields crystallization ages of 626 ±7 Ma for the protolith of the Vierrucohkka amphibolite, and 614 ±2 Ma and 609 ±1 Ma for the emplacement of the Aurek gabbro and amphibolite protolith, respectively. A younger age of 599 ±3 Ma is recorded in the Vierrucohkka amphibolite and is interpreted as the age of partial melting and migmatization. The geochemical signatures of the rocks demonstrate crustal assimilation during the emplacement of their protoliths and modification due to prograde metamorphic processes during Caledonian subduction. The Vierrucohkka amphibolite and the Aurek Assemblage samples display upper and lower crustal assimilation, respectively. Trace elements (Dy, Sm, Lu, and Y) record the growth of metamorphic garnet, while elevated TiO2contents record the crystallization of metamorphic rutile. Nevertheless, high field strength elements (HSFE) and ANb suggesta depleted mantle source forthe magmas of the protoliths of the investigated rocks. Altogether, geochemical data indicate that the igneous activity recorded in the Vierrucohkka amphibolite and the Aurek Assemblage between c. 626-609 Ma is related to continental rifting processes associated with the opening of the lapetus Ocean. [ABSTRACT FROM AUTHOR]

The MOS model (acronym coming from the French MOdèle Simplifié) was born from the desire to have a simple tool that can quantify the contribution of the diffusive reactive environment to the alteration of a vitrified nuclear waste package in deep geological disposal conditions. In the model, this environmental contribution consists partly of the ability of iron, metallic casing corrosion products, and argillite to consume silicon, and partly of the brake on diffusive transport provided by silicon through the successive layers of environmental material. It is a modeling tool serving as an intermediary between operational modeling for the calculation of the source term from the glass, mathematically more simple and giving higher upper margins, and models that use geochemistry and transport, giving greater accuracy for the interactions between glass and its environment. The goal of the MOS model is to calculate the possible impact of silicon reactive diffusion on the alteration rate within the different layers of material surrounding nuclear glass. This article lists the simplifying hypotheses on which the MOS is based, presents the digital resolution method for an environment consisting of several successive layers with different reactivity and transport properties, and explains the model's implementation. [ABSTRACT FROM AUTHOR]

In this study, laser ablation–multicollector–inductively coupled plasma–mass spectrometry (LA–MC–ICP–MS) of apatites and LA–ICP–MS of zircons are used to collect U–Pb geochronological data, Rb–Sr isotope chronology is used to analyze alkaline feldspar and plagioclase, and archival apatite geochemistry data for the exposed Naitoushan basalt and Heishigou dike in the Changbaishan Tianchi volcano (CTV) are accessed to examine the petrogenesis and determine the origin of basaltic magmatism in the CTV. The Naitoushan basalt and Heishigou dike formed at 22.2–18.7 and 0.230–0.218 Ma, respectively. In situ oxides, volatiles, trace element geochemistry and Sr–Nd isotopes of apatite are reported for two samples. Most apatites are in the early crystallization phase and form inclusions in plagioclase that are euhedral or subhedral. They have higher MgO and K2O/Na2O concentrations; lower F and Cl concentrations; Ba, Sr, Nb, Ta, Zr, Hf, K, and Ti depletion; and Th, U, Ce, Pb, P, and Nd enrichment. All apatite samples are enriched in light rare earth elements (REEs) relative to heavy REEs and have relatively homogeneous Th/U, Zr/Hf, La/Sm, and Nd/Tb ratios and Sr–Nd isotopic compositions; thus, their host magmas potentially have the same magmatic origin as oceanic island basalt. The apatite La, Yb, and U contents, Eu/Eu* and La/Yb values, and high REE contents show a weak crystallization sequence in the mafic magma. This study demonstrates that the pre-shield and post-shield mafic magmas in the CTV were likely derived from an enriched mantle source with an I-type signature related to the rollback of the Pacific plate. [ABSTRACT FROM AUTHOR]

Archaeological studies carried out in recent decades have demonstrated that the Pre‐Pyrenees, a mountain range in north‐east Iberia, were regularly frequented by several human groups during the Late Pleistocene. The Cova del Parco archaeological site is an example of this large‐scale and regular human presence. The site was discovered and first excavated in the 1970s, and since the 1980s, a team from the University of Barcelona has been conducting archaeological work. So far, we have found that the site was at least frequented from the Middle Magdalenian upon historical times. In this paper, we present the results of the archaeopetrological, geochemical and geographic information system (GIS) analyses of chert tools ascribed to the Middle Magdalenian sequence. The textural, micropalaeontological and geochemical analysis of the lithic artefacts has allowed us to identify several chert types from local, regional and long‐distance sources. Some of these cherts had their origin in the northern slopes of the Pyrenean chain, suggesting that this mountain chain was regularly crossed by Magdalenian groups. Next, we performed GIS analyses to determine the paths and connections that may have linked the archaeological site with the different chert outcrops, and to identify the best routes for crossing the Pyrenean Mountain range. Moreover, this study provides a larger vision of the mobility and the complex economic interactions between the different Magdalenian groups that settled Cova del Parco at the end of the Late Pleistocene. [ABSTRACT FROM AUTHOR]

This study discusses the potential of archaeological organic objects in anthropogenic sediments in terms of research into human impact on the medieval landscape and environment. In the Bohemian‐Moravian Highlands, at a mid‐altitudinal stream valley site (ca. 510 m asl), remains of a cut medieval forest stand with anthropogenic wooden structures and buried by technogenic sediments (e.g., ore, gangue and tailings) were archaeologically excavated. The site was analysed using an interdisciplinary approach, applying methods from archaeology, archaeobotany, sedimentology, pedology and geochemistry as well as dendrochronology and radiometric dating. The vegetation can be reconstructed as forest with a dominance of fir and an admixture of spruce and alder. The surrounding slopes were covered by broadleaf trees. Remains of wooden technical structures, stamped, ground and washed ores and gangue, together with fragments of grinding stones, allow the interpretation of the site as an ore and stamp mill linked to ore washing equipment. This record of a buried medieval fir forest can be likewise used as a historical testimony and analogue for present‐day issues on ecology and forestry, aiming at ecological revitalisation and adaptation of forests to ongoing climate change in Central Europe. [ABSTRACT FROM AUTHOR]

The content and distribution of precious metals in fine-grained bottom sediments, accumulated in the technogenic period (last decades) in the southwestern part of the Chukchi Sea, have been studied. The ubiquitous or local enrichment of the sediments with silver, gold, platinum, and palladium according to the average for the Earth's crust, as well as their enrichment with gold and palladium relative to pre-technogenic (Late Holocene) deposits, was shown. Differences in the conditions of the accumulation of precious metals in the Late Holocene and modern sediments were shown. Sources of input were determined, and the possibility of technogenic enrichment of the sources was proved by the methods of multicomponent statistical analysis of the total chemical composition of the sediments. [ABSTRACT FROM AUTHOR]

In recent years, a new Algoma-type banded iron formation (BIF) deposit has been discovered in the Lanling area of the North China Craton. However, its underlying formation origins remain elusive. To effectively address this issue, in this work, the major trace and rare earth elements were analysed to characterize their sources and formation environments. From their major geochemistry results, it was proven that the Lanling BIF is mainly composed of SiO2 + Fe2O3T with small amounts of Al2O3, MnO, K2O, CaO, MgO, Na2O, P2O5, and TiO2. After performing Post-Archean Australian Shale (PAAS) normalization, according to rare earth elements (REE) and yttrium (Y) (REE + Y = REY) analyses, it was demonstrated that light rare earths are depleted. On the contrary, heavy rare earths are enriched. In addition, La, Eu, and Y are positive anomalies, while Ce is a slightly negative anomaly. According to the REE geochemistry and REE-related parameters analyses, it was extracted that the ore-forming materials of Lanling BIF were mainly derived from the mixture of seawater and hydrothermal materials. Moreover, the formation of deposits is closely associated with seafloor hydrothermal fluids. Additionally, based on the negative Ce anomalies and REY characteristics, it was speculated that BIF formed in reducing conditions in Lanling. Our work provides valuable insights suggesting that the BIF in the study area is closely related to the volcanic sedimentary rock series, as well as to the possible existence of pyroclastic materials. [ABSTRACT FROM AUTHOR]

This study investigates the diagenetic history and timing of hydrocarbon migration in the lower Permian Ingleside Formation as revealed in the Ingleside roadcut at Owl Canyon area, Colorado. Fourteen beds were identified within the studied exposure and are composed of quartz arenite sandstone, limestone, dolomite, or siltstone. Observations from outcrop and thin sections, including calcite veins, carbonate-hosted vugs, and carbonate cement, indicate carbonate mobility throughout the outcrop. Stylolites parallel to bedding were probably formed by pressure solution related to compaction, and pressure solution of carbonates is one possible source of carbonate that could have precipitated in veins or as a cement. The Ingleside Formation was affected by other diagenetic processes, including feldspar dissolution and alteration and several stages of cementation. Hematite, calcite, dolomite, kaolinite, and quartz overgrowth cements are the major types of cements identified within the studied exposure. Hematite cement was determined to have precipitated very early, followed immediately by the precipitation of poikilotopic carbonate cement. Blocky calcite and blocky dolomite cements, the most common cements within the formation, formed after the hematite and poikilotopic cements. Kaolinite cement may have precipitated in association with feldspar dissolution and alteration or occurred with feldspar dissolution during modern weathering. Hydrocarbon migration may have taken place before the of the blocky carbonate cement. The CaO in sandstone samples is due to the occurrence of calcite and dolomite cement. The MgO in sandstone samples is related to dolomite content. Furthermore, the low concentration of K2O in sandstone samples could be attributed to the low proportion of K-feldspar, and other K-rich minerals and possibly reflects loss of K during diagenesis. The relationship fact that S and MgO are both more abundant in samples from the middle and upper parts of the outcrop than in deeper samples suggests that they were added by diagenetic fluids. This study of the Ingleside outcrop provides insights on the diagenesis, possible timing of possible hydrocarbon migration through the Ingleside Formation, and geochemical and mineralogical composition of the exposure, which was used to interpret the diagenetic history throughout the outcrop. Therefore, it adds to the understanding of hydrocarbon migration and hydrocarbon pathways in this part of the Denver Basin. [ABSTRACT FROM AUTHOR]

The carbonate rocks in the eastern part of NE Turkey are situated within the Pontide paleo-magmatic arc and are frequently in contact with granitoid formations, often hosting skarn mineralization in the region. These carbonate rocks, typically found on ridges and hillsides exhibit predominant orientations along east–west, northeast-southwest, and northwest-southeast directions. A part of limestone, named as biomicrite, metamorphosed and display a saccharoidal texture. Comprised mainly of calcite, with less secondary quartz and iron oxide minerals, these carbonate rocks are classified as Fe-poor calcio-carbonate and magnesio-carbonate, having higher CaO and LOI contents. Marble and recrystallized limestone with granoblastic texture mainly comprise of calcite, less quartz, magnetite, and hematite. Marble classification diagrams suggest calcic skarn mineralization, indicated by decreasing CaO (or CO2) and increasing MgO from limestone to marble (or skarn). Strontium contents deviate slightly from the lithosphere carbonate average, while low Rb contents, attributed to skarn metamorphism, indicate the absence of K-bearing minerals. The high Al2O3/SiO2 in the carbonate rocks can points out hydrothermal activity and carbonate disengagement can indicate to actualize at temperatures that can affect Ce and Al mobilities. The low authigenic U value, low U/Th and Ni/Co ratios in carbonate rocks have been implied that protolith constituents deposited under oxic conditions. Positive Eu anomalies in limestone and marble suggest the influence of hydrothermal fluids. Carbon and oxygen isotope values in marble are similar with those of metamorphic and skarn marbles, indicating a magmatic origin. Overall, mineralogical and geochemical analyses propose a uniform source and/or geological process for all studied marbles. [ABSTRACT FROM AUTHOR]

The Neoarchean Qingyuan greenstone belt (QGB) is located at the northeastern margin of the North China Craton (NCC) and has experienced amphibolite- to granulite-facies metamorphism. The supracrustal rock assemblage is composed of biotite-hornblende (Bt-Hb) monzonitic gneiss, garnet-biotite-hornblende (Grt-Bt-Hb) monzonitic gneiss, Grt-Bt-Hb plagioclase gneiss, amphibolite and orthopyroxene-biotite-hornblende (Opx-Bt-Hb) plagioclase gneiss. This study involves thorough field and petrographic observations, whole-rock geochemistry and LA-ICP-MS zircon U‒Pb ages of these rocks to constrain the Neoarchean geodynamic setting of the QGB. Zircon U‒Pb dating indicates that these metavolcanic rocks formed during 2.57‒2.52 Ga and experienced subsequent regional metamorphism at 2.52‒2.47 Ga. Lithological and geochemical characteristics show that the QGB protoliths were tholeiitic to calc-alkaline basalts, andesites, dacites and rhyolites. The andesite-dacite-rhyolite assemblage exhibits high SiO2 and Mg# values, low Yb and Y contents, strongly fractionated chondrite-normalized REE patterns and depletion in Nb, Ta, Ti and P, resembling Phanerozoic adakites. These geochemical characteristics suggest an origin from the partial melting of a subducted slab interacting with mantle wedge material. The tholeiitic to calc-alkaline basalts exhibit slightly LREE-enriched chondrite-normalized REE patterns and negative Nb and Ti anomalies, like island arc basalts. These basalts might have originated by partial melting of a mantle source affected by metasomatism from subduction-derived fluids and melts. The lithological associations and geochemical characteristics imply that the Qingyuan greenstone belt developed in a continental margin arc setting. [ABSTRACT FROM AUTHOR]

Reliable reconstructions of tephrostratigraphy and emplacement mechanisms of Early to Middle Miocene volcaniclastic deposits across the Alpine-Mediterranean region may yield important clues as to the nature, spread, volume, magnitude and frequency of large silicic eruptions of the Carpathian-Pannonian Region. Here we report on a sequence of Middle Miocene volcaniclastic deposits intercalated with lacustrine strata from the Livno-Tomislavgrad Basin, part of the Dinaride Lake System. We applied a multi-proxy approach to elucidate their source, decipher their emplacement mechanism, and evaluate their basin-scale and regional correlativity. New high-precision zircon geochronology (~ 14.32 Ma) reveals their simultaneity with numerous volcaniclastic deposits (and their alteration products) widely spread across the Alpine-Mediterranean region. Additionally, their correlativity is confirmed at the scale of the Livno-Tomislavgrad Basin, based on similar lithostratigraphy, mineralogy and volcanic glass geochemistry. Newly obtained zircon Hf isotope data imply that Livno-Tomislavgrad Basin distal volcaniclastic deposits and ~ 14.36 Ma Harsány ignimbrite of the Carpathian-Pannonian Region had shared a parental eruptive center. However, different volcanic glass geochemistry, bolstered by the high-precision geochronology, suggests distinct eruption events, implying more frequent explosive volcanism of the Carpathian-Pannonian Region during Middle Miocene than previously recognized. We suggest that the ~ 14.32 Ma fine fallout tephra, deposited in the distal basin in the Dinarides (> 400 km from the source), was likely re-mobilized by water-driven hillside erosion from the extensive paleo-relief, and further transported via land-derived gravity flows. Upon entering the lake, the gravity flows likely transformed into subaqueous sediment density flows. These deposited ~ 1 to 7-m-thick overall graded volcaniclastic turbidites, thinning away from the presumed source of tephra re-mobilization. Although over-thickened, the ~ 14.32 Ma Livno-Tomislavgrad Basin volcaniclastic deposits can still serve as a reliable tephro- and tectono-stratigraphic markers due to their rapid mode of accumulation. Schematic illustration of the formation of studied ~14.32 Ma volcaniclastic successions of the SE Livno-Tomislavgrad Basin, Dinaride Lake System [ABSTRACT FROM AUTHOR]

The Sierra de Famatina of northwestern Argentina contains one of the best Cambro-Ordovician stratigraphic records of the SW Gondwana margin. Two lithotectonic belts (Calalaste–Narváez and Famatina–Valle Fértil), separated by master faults, preserve evidence of two former volcano-sedimentary basins (Eastern and Western, respectively). The Calalaste–Narváez Lithotectonic Belt consists of an Ediacaran to early Cambrian basement unconformably overlain by a 490–480 Ma cover of very low-grade volcano-sedimentary and volcanic succession that presumably formed in an extensional tectonic regime. In contrast, the Famatina–Valle Fértil Lithotectonic Belt comprises a basement consisting of the late-lower-to-middle Cambrian metasedimentary Achavil and Negro Peinado formations unconformably overlain by meta/sedimentary and metavolcanic rocks ranging in age from the late Cambrian to the Middle Ordovician (ca. 490–460 Ma). This belt includes the Famatinian Cordilleran-type magmatic arc active mainly at ca. 473–468 Ma, coeval with andesite to rhyolitic volcanism (Suri and Las Planchadas formations). Rhyolitic tuffs of ca. 473 Ma (εNdi = − 4.1) were found in the La Aguadita Formation, allowing this unit to be re-assigned to the late Floian. The oldest magmatism of the Sierra de Famatina is characterized by isotopically evolved (εNdi = − 5.1) rhyolitic tuffs of ca. 490 Ma in the Bordo Atravesado Formation, which was coeval with deposition of Mn-enriched hydrothermal cherts. This early Famatinan volcanism contrast with that of similar age and isotopically less evolved occurred in the Calalaste–Narváez Lithotectonic Belt suggesting variations of the source of magmas across the space and time within the Famatinan Orogenic Cycle. We propose that both described lithotectonic belts likely diverge northwards into Chile and Peru, wrapping around the Arequipa–Antofalla Proterozoic block. [ABSTRACT FROM AUTHOR]

Deep biospheric anaerobic microbial sulfate reduction and oxidative sulfur cycling have been studied in long sediment cores mainly acquired as part of IODP explorations. The most remarkable observation in many of these studies is the existence of an active sulfur cycle in the deep subsurface sediments that have very low organic carbon content and are presumably refractory. Here, we investigate the interstitial sulfate concentrations and sulfur isotope ratios in a 290 m-long sediment core collected from the eastern Arabian Sea at a water depth of 2663 m. Continuous decrease in porewater-sulfate concentrations with depth (up to 75 mbsf) coupled with enrichment in δ34SSO4 values suggests organoclastic sulfate reduction (OSR) processes attributed to the activity of sulfate-reducing bacteria (SRB) and retention of labile organic substrates amenable to the SRBs. Below a depth of 75 mbsf, the absence of further reduction in sulfate concentration indicates insufficient labile substrate to drive sulfate-reduction activity. An increase in sulfate concentrations at the deeper subsurface (below 128.5 mbsf) coupled with decreasing δ34SSO4 values may be attributed to the oxidation of Fe-sulfide to sulfate. The increase in porewater alkalinity in the lower part of the core has been linked to the silicate degradation process by CO2 produced via the dissolution of CaCO3. Compilation of previous studies from this core, along with our investigation, intrigues future research on organic matter reactivity and microbiological activity in deeper subsurface under oligotrophic depositional regimes. [ABSTRACT FROM AUTHOR]

The Pannonian Basin is one of the best natural laboratories in the world to study the lithospheric response to continental extension and subsequent tectonic inversion. Here we address the topic of lithospheric structure by a combined geochemical and magnetotelluric analysis, which has been carried out in the framework of the Pannon LitH2Oscope project. The main objective was to detect the resistivity distribution over the entire lithosphere by magnetotelluric measurements, considering the lithological resistivity properties and relate the results to the structure and evolution of the Pannonian Basin. The Pannon LitH2Oscope MT array was used to estimate the depth of the Lithosphere-Asthenosphere Boundary (LAB), considering the legacy MT data and compared to previous estimates for the region. Using the MT and geomagnetic response functions, major structural zones of the Pannonian basin, such as the Mid-Hungarian Shear Zone or fault systems like the Makó Trough and the Békés Basin, were also imaged. In addition, we used the apparent resistivity soundings to compare 1D resistivity models computed from geochemistry and obtained from field MT measurements. This comparison provided new constrains for the composition, fluid and melt content variations at the local lithosphere-asthenosphere boundary. The Pannon LitH2Oscope MT dataset and the results presented in this paper provide input for more complex 3D inversions and further investigations of the lithospheric structure in the Carpathian-Pannonian region. [ABSTRACT FROM AUTHOR]

The East Kunlun Orogenic Belt, an important part of the Central Orogenic Belt in China, preserved wealthy geological information for the tectonic evolution of the Proto- and Paleo-Tethys Ocean. Several Permian mafic-ultramafic rocks were identified in the Qimantagh area, EKOB, and zircon U-Pb dating, zircon Hf isotope, geochemistry and whole-rock Sr-Nd isotopes were studied in this paper. The results suggest that the formation age of the Xiyingzhaogou intrusion is 280 ± 4 Ma. The rocks show the characteristics of continental-arc calc-alkaline basalt. The whole-rock εNd(t) value of gabbro in Xiyingzhaogou intrusion is −4.2~-2.6 and the εHf(t) value of zircon is 2.77 ~ 5.82, indicating the characteristics of enriched or weakly depleted mantle; The formation age of Yingzhaogou intrusion is 263 ± 4 Ma. The geochemical characteristics of the Yinzhaogou rocks are consistent with those of continental-arc tholeiite. The whole-rock εNd(t) value of gabbro in Yingzhaogou intrusion is 0.73 ~ 0.92, and the εHf(t) value of zircon is 8.33 ~ 13.50, indicating the characteristics of depleted mantle. We believe that the Xiyingzhaogou intrusion was formed in the Early Permian and originated from the mantle wedge metasomatized by subduction fluid. The Yingzhaogou intrusion was formed in an extensional continental-arc environment caused by the retreat of the subduction plate. Asthenospheric mantle and fluid metasomatic lithospheric mantle were jointly involved in the mantle source. This study confirmed that the subduction of the Paleo-Tethys oceanic slab should had started before the Early Permian and a wide magma arc formed due to flat subduction. The retreat of the subduction plate led to the extension of the East Kunlun region, resulting in the significant enhancement of magmatism in the Middle Permian. [ABSTRACT FROM AUTHOR]

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The geochemistry of Paleogene strata (sandstones and shales) of the N'kapa Formation in part of the western Douala Basin has been studied through major, trace, and rare earth elements (REEs) in order to understand their provenance and tectonic settings. The NF sandstones and shale are clustered around granodiorite with minor contributions from granitic source. The samples show high and fairly constant Th/Sc ratios 0.64–6.9 for sandstone and 1.01–8.7 for shale that strongly indicate provenance from a relatively evolved igneous source (mafic) also different geochemical signatures of Eu/Eu*, La/Sc, La/Co, Th/Sc, Th/Co, Zr/Sc, Cr/V, and Y/Ni ratios, and their plots suggest a mafic igneous provenance with substantial sediment recycling. Geochemical signatures from plots of The La/Th–Hf diagram, La/Sc vs Ti/Zr, and Fe2O3 + MgO vs TiO2 tectonic discrimination diagrams show that the studied rocks were deposited mainly in a passive continental margin setting. The large quantities of alkalis classify the rocks as wackes, Fe-sand, shale, and Fe-shale. The studied lithofacies have been classified based on Al–Fe-Mn enrichment as follows: terrigenous and metalliferous rocks. [ABSTRACT FROM AUTHOR]

An investigation was done to determine the texture, organic matter content, and geochemical characteristics of sediments collected from the continental shelf of the South Western Bay of Bengal. The present study portrays the abundance of sand followed by slightly muddy sand, muddy sand, sandy mud, sandy, and slightly sandy mud in the study area. The mean size of the sediment ranges from 0.40 to 3.57 mm (coarse sand to very fine sand). The sediments are very well to very poorly sorted, coarsely skewed to fine skewed, and platykurtic to very leptokurtic in nature. Trace metals, such as Cu, Co, Fe, Mn, Pb, Zn, Cr, and Ni were analyzed. A relatively high percentage of organic matter is attributed to the predominance of finer sediments entering through the minor and major rivers. The higher trace metal concentration in the study area is closely associated with mud content and Fe is the most abundant trace metal in the study area. Formation of Fe- and Mn-hydroxides in the near-shore regions is responsible for scavenging Pb, Zn, Cu, Ni, and Cr and effectively incorporating them into the inner shelf sediments. Among all the trace metals, the concentration of Co, Pb, Cr, and Ni is found to be higher than the average crustal abundance value marking the role of anthropogenic sources predominantly from industrial, agricultural, scrap metal recycling, sewage, and tourism activities. [ABSTRACT FROM AUTHOR]

Uzbekistan (Central Asia) is experiencing serious water stress as a consequence of altered climate regime, past over-exploitation, and dependence from neighboring countries for water supply. The Chirchik–Akhangaran drainage basin, in the Tashkent province of Uzbekistan, includes watersheds from the Middle Tien Shan Mountains escarpments and the downstream floodplain of the Chirchik and Akhangaran rivers, major tributaries of the Syrdarya river. Water in the Chirchik–Akhangaran basin is facing potential anthropogenic pressure from different sources at the scale of river reaches, from both industrial and agricultural activities. In this study, the major and trace element chemistry of surface water and groundwater from the Chirchik–Akhangaran basin were investigated, with the aim of addressing the geogenic and anthropogenic contributions to the dissolved load. The results indicate that the geochemistry of water from the upstream catchments reflects the weathering of exposed lithologies. A significant increase in Na+, K+, SO42−, Cl−, and NO3− was observed downstream, indicating loadings from fertilizers used in croplands. However, quality parameters suggest that waters are generally suitable for irrigation purposes, even if the total dissolved solid indicates a possible salinity hazard. The concentration of trace elements (including potentially toxic elements) was lower than the thresholds set for water quality by different regulations. However, an exceedingly high concentration of Zn, Mo, Sb, Pb, Ni, U, As, and B compared with the average river water worldwide was observed. Water in a coal fly-ash large pond related to the Angren coal-fired power plants stands out for the high As, Al, B, Mo, and Sb concentration, having a groundwater contamination potential during infiltration. Spring waters used for drinking purposes meet the World Health Organization and the Republic of Uzbekistan quality standards. However, a surveillance of such drinking-water supplies is suggested. The obtained results are indicators for an improved water resource management. [ABSTRACT FROM AUTHOR]

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Osmotic water alters the physicochemical properties and internal structures of limestone. This issue is particularly critical in tunnel construction across mountainous regions with aquifers, where pressurized groundwater can destabilize the limestone-based surrounding rock. Thus, systematic research into the physicochemical properties and pore structure changes in the limestone under pressurized water is essential. Additionally, it is essential to develop an interpretable mathematical model to accurately depict how pressurized osmotic water weakens limestone. In this research, a specialized device was designed to simulate the process of osmotic laminar flow within limestone. Then, four main tests were conducted: mass loss, acoustic emission (AE), mercury intrusion porosimetry (MIP), and fluorescence analysis. Experimental results gained from tests led to the development of a "Particle-pore throat-water film" model. Proposed model explains water-induced physicochemical and pore changes in limestone under osmotic pressure and reveals evolutionary mechanisms as pressure increases. Based on experimental results and model, we found that osmotic pressure not only alters limestone composition but also affects pore throats larger than 0.1 µm. Furthermore, osmotic pressure expands pore throats, enhancing pore structure uniformity, interconnectivity, and permeability. These effects are observed at a threshold of 7.5 MPa, where cohesive forces within the mineral lattice are surpassed, leading to the breakdown of erosion-resistant layer and a significant increase in hydrochemical erosion. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the distribution of lanthanum, thorium, and uranium content in soils from the Mitrovica region in the Republic of Kosovo. For this purpose, 156 samples of topsoil (0–5 cm) were considered in a sampling network of 1.4 × 1.4 km2. The soil samples were prepared using the aqua regia digestion method and analyzed using inductively coupled plasma mass spectrometry. The contents of La, Th, and U in the soil of the study area were determined to be 19, 4.8, and 0.84 mg/kg, respectively. The enrichment factor values for La, Th, and U ranged from 3.8 to 7.9, 3.2 to 7.0, and 2.0 to 7.0, respectively, indicating moderate to substantial enrichment. The geo‐accumulation index values of all elements were less than zero, indicating uncontaminated levels. The spatial distribution patterns of La, Th, and U content showed that the values are elevated in the north‐eastern and western parts of the study area, where Miocene latites and quartz latites predominate (average contents of 35, 2.4, and 2.1 mg/kg, respectively). These areas are located in rural areas, suggesting that the high La, Th, and U contents in the soil are related to the lithology of the study area and there is no influence of possible anthropogenic sources. This study contributes to the database of La, Th, and U contents in the soils of the Mitrovica region and allows an assessment of the relationship between geochemistry and ecosystem health. [ABSTRACT FROM AUTHOR]

The sandstone uranium deposits in the Kelulun Depression are the first commercially viable uranium deposits discovered in the Hailar Basin and the ore-bearing strata corresponding to the Lower Cretaceous Yimin Formation. However, the source of sedimentary matter, uranium source conditions, and uranium mineralization processes in the region have not been characterized. Accordingly, we analyzed the lithology, whole-rock geochemistry, zircon U-Pb ages, and trace elements of the Yimin Formation sandstones. The Yimin Formation sandstones were primarily composed of detrital grains with low compositional maturity. A geochemical analysis indicated that the parent rocks are felsic igneous rocks formed at an active continental margin with a moderately high degree of weathering. The detrital zircon U-Pb ages of the Yimin Formation 215–287 Ma with a peak at 230–260 Ma. Based on chronological, geochemical, and lithological data, we conclude that the Yimin Formation matter is derived from the Adunchulu Uplift on the western side of the Kelulun Depression and its parent rocks are Triassic granites. The Adunchulu uplift since the late Early Cretaceous and weathering and denudation of its uranium-rich granites provided ample matter and uranium. Therefore, the Kelulun Depression is a promising area for the exploration of sandstone uranium deposits. [ABSTRACT FROM AUTHOR]

This paper presents a complete map of the Mesozoic volcanic-plutonic complexes in the Taiwan Strait and its adjacent areas in terms of seismic profiles, ages, geochemistry, isotopic systematics, and published data. Two periods of igneous activity in the Taiwan Strait can be distinguished by seismic profiles: Jurassic (200.4–148.2 Ma); and Latest Jurassic/Cretaceous to Maastrichtian (144–66 Ma), of which the Cretaceous is the best preserved and could possibly be the most widespread. Mesozoic magmatic activity with the NE-striking distribution was migrating southeastward (oceanward). LA-MC-ICPMS zircon U – Pb dating yields the age data of 109.5 ± 0.4 Ma for PTDH1 granodiorite and 92.6 ± 0.4 Ma for PTDH4 rhyolite in the Taiwan Strait, respectively. The 581.66-m-thick Upper Jurassic volcanic rocks of the Chuan2 well are the thickest Mesozoic igneous rocks in the Taiwan Strait. The petrogenetic discrimination diagram of the Cretaceous volcanic-plutonic complexes along the coast of South China and the Taiwan Strait generally is belonging to volcanic arc or intraplate type calc-alkaline rock series. The high potassium calc-alkaline rock series of the Cretaceous volcanic-plutonic complexes that is most widely distributed in the coastal areas of South China and the Taiwan Strait. They are controlled by the subduction of the Palaeo-Pacific domain. [ABSTRACT FROM AUTHOR]

Metacarbonates serve as proxies for understanding the chemical oceanography of the present, as well as the past-day ocean’s evolution history and these are extensively described in the Neoproterozoic-Cambrian collisional belts of East Gondwana. The Cauvery Suture Zone (CSZ), Southern Granulite Terrane (SGT), India, is one such prominent example of their occurrence, along with several Precambrian dismembered ophiolites, arc-related intrusions and other metamorphic rocks. These are dominantly exposed in the western, southern and south-central parts of the suture, around the Neoproterozoic Kadavur Gabbro-Anorthosite and Manamedu Ophiolite Complexes. Their whole-rock geochemistry reveals the protoliths of metacarbonates have been derived from different sources of continental inputs and deposited under open to passive margin settings. The δ13C(V-PDB)) - δ18O(V-SMOW) data (−0.01 to + 3.03‰; +15.81 to + 24.84‰) reveal as high-temperature carbonates of typical limestone variety, deposited under warmer palaeoclimatic conditions of the marine environment and later subjected to metamorphism. The presence of higher 87Sr/86Sr ratios (0.707514 to 0.71511) and negative εNd values (−17.3 to −10) suggests that they originated from large crustal inputs with more interactions of seawater with the sediments, evolved during Ediacaran to early Cambrian periods. The above results reveal that these are possible remnants of the Neoproterozoic Mozambique Ocean and coeval with the metacarbonates of Sør Rondane Mountains-East Antarctica, Highland Complex-Sri Lanka, Madagascar and Mozambique Belts of Neoproterozoic Gondwana. [ABSTRACT FROM AUTHOR]

Abstract\nKEY POINTSThe extensive middle Cambrian evaporite platform dolostone represents a significant area for hydrocarbon exploration in the Tarim Basin with recent advances indicating promising exploration prospects. However, owing to its considerable depth and the limited exploration, the genesis and distribution of evaporite-related dolostone reservoirs from the middle Cambrian remain poorly understood. This study includes detailed field investigations along with petrological, mineralogical and geochemical analyses to characterise the secondary porosity of the middle Cambrian Shaelek Formation evaporite platform dolostone and to explore the origin of the diagenetic fluids responsible for these features. The results show that gypsum dissolution vugs are the main secondary porosity in the evaporite platform dolostone reservoirs, with their development and distribution strongly controlled by sedimentary facies. Meteoric dissolution during the penecontemporaneous period is responsible for this secondary porosity. The frequent fluctuation in sea-levels and the transient exposure of the dolostone reservoirs provide favourable conditions for the dissolution of unstable gypsum. The multiple stages of calcite filling in the vugs result from supersaturated precipitation from fluids during the late stage of meteoric diagenesis. Variations in δ13C, δ18O and rare earth element compositions between the two types of calcite reflect different stages of fluid evolution and varying degrees of water–rock reaction. The vug-filling fluorite is of non-hydrothermal genesis but results from the highly evaporative concentrated seawater and terrigenous input. The highly concentrated F– in evaporative seawater, combined with F– from fluvial input (if any) during subaerial exposure, most likely provides the F– necessary for fluorite precipitation. A model of reservoir formation and evolution has been established that will be beneficial for hydrocarbon exploration and prediction of the deeply buried Cambrian evaporite platform dolostone reservoir.Two types of vug-filling calcite represent the different stages of meteoric diagenesis.Non-hydrothermal fluorite occurs in the middle Cambrian evaporite platform dolostone.Meteoric dissolution, rather than hydrothermal dissolution, is responsible for the vugs in the evaporite platform dolomite.An evolution model for the middle Cambrian evaporite platform dolomite reservoir is established. [ABSTRACT FROM AUTHOR]

The Triassic tectonic evolution and affinity among the Yangtze Block, Qinling Orogenic Belt and Songpan-Ganzi Terrane remain subjects of ongoing scientific debate. In this context, the sedimentary rocks of Xujiahe Formation (second segment) (T3x2) represent an ideal case for addressing this issue. In this study, new stratigraphic, geochemical and detrital zircon analyses have been conducted on two sections of the T3x2. The stratigraphic assemblage and features suggests a braided delta as the depositional setting. Whole-rock geochemical results indicate that the sandstones from the T3x2 exhibit moderate palaeo-weathering and primarily originate from upper crustal felsic rocks, mostly S-type granites. The detrital zircons within these sandstones display distinctive age peaks at intervals of 200-300 Ma, 700-900 Ma, and 1800-2000 Ma, similar to those from the Qinling Orogenic Belt. Both the clastic particle composition and whole-rock geochemistry indicates that the T3x2 sections were deposited in a tectonic environment transitioning from a passive to an active continental margin, highlighted by a braided delta influenced by rivers flowing from the northeast to the southwest. [ABSTRACT FROM AUTHOR]

The Lesser Xing'an—Zhangguangcai Range of northeast China is located in the eastern segment of the Central Asian Orogenic Belt (CAOB), which records intense magmatism during the Mesozoic. The petrogenesis and geodynamic setting of the Early Jurassic intrusive rocks in this region are unclear. In this paper, we present new zircon U–Pb age and whole-rock geochemical data for these intrusive rocks to investigate their origins and tectonic setting. Zircon U–Pb dating suggests these intrusive rocks were emplaced during the Early Jurassic (197–187 Ma). The granites are enriched in silica and alkali, and depleted in MgO and CaO. They are metaluminous to weakly peraluminous, and have high A/CNK values and low zircon saturation temperatures (TZr ~ 779°C), suggesting they are highly fractionated I-type granites derived by partial melting of lower crustal materials. The granites exhibit negative Nb, Ta, P, Eu, and Ti anomalies due to fractional crystallization. The diorites and gabbros have low SiO2 contents and high Mg# values, and are enriched in light rare earth and large-ion lithophile (Ba, K, and Sr) elements, and depleted in heavy rare earth and high field strength (Nb, Ta, and Ti) elements. The geochemical characteristics show that the mafic magmas were derived by partial melting of mantle that had been metasomatized by subduction-related fluids. Based on the geochemical characteristics of coeval intrusive rocks and the regional geological setting, we suggest the Early Jurassic intrusive rocks in the Lesser Xing'an—Zhangguangcai Range were formed along an active continental margin, possibly as a result of bidirectional subduction of the Mudanjiang Oceanic plate between the Jiamusi and Songnen—Zhangguangcai Range massifs. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the metal geochemistry and contamination assessment of the metals such as Fe, Co, Cd, Pb, Ni, Zn, Mg, Ca, and Sr from the surface sediment samples collected from seven stations from a tropical mangrove area in the Southwest coast of India. Metals like Ni and Fe were found in higher concentrations but never exceeded the contamination level in all the seasons whereas Cd was highly contaminated in all the seasons as well as stations. Pollution levels were measured using the indices including contamination Factor (CF), potential ecological risk coefficient (Eir), Enrichment Factor (EF), geoaccumulation index (Igeo), Pollution load index (PLI), Contamination degree (Cdegree), modified contamination degree (mCd) and Hazard Quotient (HQ). However, the level of contamination highlighted Cd has the maximum risk factors from the selected study area. All stations are contaminated by anthropogenic inputs. The pollution load index (PLI) revealed Pazhayangady, Valapattanam, Dharmadom (stations 1,2 and 3), Kumbalam (station5) and Munroe Thuruth (station 7) showed the presence of polluted sediments (PLI> 1). [ABSTRACT FROM AUTHOR]

Our current knowledge regarding the distribution patterns of ancient and recent recycled materials, as well as the origin of intraplate basalts in the eastern Asia Big Mantle Wedge (BMW), is limited. To address this, we conducted a detailed geochemical analysis of olivine melt inclusions (OLMI) in nephelinite samples. The normal OLMIs detected in our investigation exhibit geochemical features that closely resemble those of the hosting nephelinite, indicating a consistent association with a carbonated mantle source. Additionally, we identified a distinct group of anomalous OLMIs that displayed different geochemical characteristics from the hosting nephelinite but showed similarities to regional alkali basalts sourced from pyroxenite. The observed geochemical diversity in the nephelinite OLMIs suggests an interaction between deeply derived carbonated melts originating from the flattened Pacific slab in the mantle transition zone and pyroxenite in the lithospheric mantle. Carbonated fluid‐fluxed melting is key to basalt formation in the BMW. Plain Language Summary: The Big Mantle Wedge (BMW) refers to the mantle regions situated between the flattened subducted slab in the mantle transition zone (MTZ) and the overlying plates. In order to better understand the distribution patterns of recycled materials and the origin of intraplate basalts within the Eastern Asia BMW, we have focused on studying the Cenozoic basalts from the eastern North China region. Initially, it was believed that these basalts were formed through decompression melting of the mantle caused by back‐arc extension associated with the subduction of the Pacific plate. However, recent studies have revealed unique characteristics of these basalts, such as high water content and isotopic values that differ from those of the depleted mantle. This suggests a possible connection between the basalts and decarbonation and dehydration processes occurring within the stagnant subducted slab in the MTZ. According to the proposed model, carbonated melts/fluids released from the stagnant slab interacted with the lithospheric mantle, resulting in the transformation of the melts and the involvement of pyroxenite in the lithospheric mantle. The pyroxenite forms through ancient melt metasomatism events. This interaction ultimately leads to the generation of basalts with a wide range of SiO2 content. Key Points: The olivine melt inclusions (OLMI) originate from either a carbonated mantle source or ancient pyroxenite in the lithosphereThe geochemical diversity in the OLMI reflects the interaction between deeply derived carbonated melts and pyroxeniteCarbonated fluid‐fluxed melting stands as a crucial mechanism in the formation of basalt within the Big Mantle Wedge [ABSTRACT FROM AUTHOR]

Hydrothermal activity is widespread in sedimentary basins, but its dual effects (chemistry and temperature) on shale reservoirs are rarely discussed. In this research, we systematically collected 33 well core samples from Q1 to Q9 units in Gulong Sag, Songliao Basin, and analyzed them using a variety of analytical techniques, including a field emission scanning electron microscopy (FE-SEM), an energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), and stable C-O isotopes. Combined with the collected vitrinite reflectance (Ro), total organic carbon (TOC), and soluble hydrocarbon content data, which is the sum of free oil (pyrolysis S1) and sorb oil content (pyrolysis S2), the results show that (1) Q4 and Q8 units have large amounts of hydrothermal minerals, and its C-O isotope obviously shifts to negative, which implied those units are the main hydrothermal fluid influence area; (2) the hydrothermal activity occurred in the late depositional period of Q1–Q9 units such that its geochemistry has little effect on the proliferation of algae blooms, but its high temperature calculated by δ18O temperature formulas (around 208 °C) promoted the organic matter maturation process around Q4 and Q8; and (3) the overpressure caused by hydrothermal activity protected the shale reservoir and minimized the decrease in mineral reservoir brittleness index caused by hydrothermal fluid influence. We suggest that the shale reservoir affected by hydrothermal fluid will become a good geology "dessert", and its upper and/or lower bounds can form an engineering "dessert" due to the precipitation of large amounts of brittle carbonate minerals. [ABSTRACT FROM AUTHOR]