Understanding fault activity over time provides valuable insights for reconstructing the tectonic history of an orogen, assessing seismological risks and understanding mineralization processes. In the Western Alps, one of the main controversies in existing tectonic models is the understanding of syn-orogenic extension. Seismological evidence shows widespread extensional deformation related to the reactivation of major lithospheric structures, such as the Penninic Frontal Thrust (PFT). However, the onset age and origin of extension are still debated due to the lack of suitable geochronological data. Fault hematite and calcite geochronology as well as clumped isotope data can be used to relate fluid regimes to fault activity. The analysis of calcite brecciae from extensional faults above the PFT shows that two distinct fluid regimes were present. The first regime, occurring before 2 Ma is associated with upwelling of deep fluids and is recorded by fault calcite at a temperature > 110°C. The second fluid regime is characterized by a meteoric signature and temperatures around 36 °C, representing crystallization since 2 Ma. This study presents a new model for the Miocene tectonic history of the Western Alps that combines (U-Th)/He and U-Pb geochronology on fault hematite (13.3 ± 0.8 to < 0.8 Ma) and calcite (5.3 ± 0.6 Ma). Results demonstrate a progression of extensional fault activity from east to west, from the Middle Miocene (ca. 13 Ma) to the Quaternary. The onset of extension in the inner part of the belt coincides with the development of the fold and thrust belt in the western Alpine foreland. Our new model proposes that extension occurs in the hanging wall of a large top-to-the-west thrust, known as the Alpine Frontal Thrust. This thrust, located to the west of the External Crystalline Massifs gives rise to their uplifting and extension at the rear.
The western periphery of Baltica has traditionally been viewed as a passive continental margin formed during the fragmentation of Rodinia and the opening of the Iapetus and Tornquist Oceans. This view is supported by the Volyn Large Igneous Province (VLIP) of Ediacaran age in Eastern Europe, which may be associated with break-up and evolution of the Tornquist Ocean. However, in western Ukraine, the sedimentary succession overlying the VLIP contains latest Ediacaran to early Cambrian detrital zircon with mixed εHf(t) values that can be interpreted to reflect deposition in a convergent margin setting with input from a continental volcanic arc. To investigate the potential convergent tectonic setting along SW Baltica during the Ediacaran to Cambrian transition, we conducted research in the Holy Cross Mts. (HCM), Poland. Here, tightly folded, and low-grade metamorphosed slates are unconformably overlain by Lower Ordovician (Tremadocian) sedimentary rocks. We applied 40Ar/39Ar geochronology on white mica defining cleavage in lower Cambrian rocks and U-Pb geochronology on detrital zircons to constrain the timing of the deformation. Our samples show similar populations of detrital zircons, with affinities to regions within or on the outskirts of Baltica. For all Cambrian samples, the calculated maximum depositional age is close to their stratigraphic age, suggesting rapid deposition in an active tectonic setting. The εHf(t) values range from −18 to +12, indicating significant mixing of mantle-derived magmas with mature crustal material typical of continental magmatic arc systems. Single-grain fusion 40Ar/39Ar geochronology on white mica yielded two populations of weighted average ages of 537 ± 1 Ma and 510 ± 4.4 Ma, interpreted as a detrital white mica population and the maximum approximation of the age of post-depositional early to middle Cambrian deformation, respectively. The similarities in zircon populations and isotopic compositions between Cambrian sediments of the HCM and those from Ukraine, suggest that both areas were sourced from a continental arc on the Baltica margin, above a subduction zone consuming Neoproterozoic Mirovoi Ocean crust. This arc is likely an equivalent to the Cadomian Arc on the opposite side of the ocean.
The Lower Tieshajie Subgroup at the conjunction zone of the Yangzte and Cathaysia blocks represents the only Stenian sedimentary succession in the eastern Jiangnan (Sibao) Orogen of South China, bearing important clues on plate boundary and pre-Neoproterozoic crustal evolution. We report the first U-Pb and Hf isotopic data of detrital zircons from this succession to investigate the age and provenance characteristics. Age and Hf isotopic compositions of detrital zircons from the lower and upper parts of the metamorphosed Lower Tieshajie Subgroup are similar. They are exclusively of magmatic origins, showing youngest age peaks at ca. 1.17 Ga and ca. 1.15 Ga, respectively, but both with a rarity of 1.12–1.10 Ga ages from the nearby magmatic rocks. This constrains protolith deposition of the Lower Tieshajie Subgroup to be mainly at 1.17–1.12 Ga, while the timing of metamorphism is bracketed by the intruding unmetamorphosed granites to be 1.10–0.84 Ga, that is, related to Grenville-aged orogenesis at the Jiangnan Orogen. The detrital zircons yielded a broad age range of 3.28–1.03 Ga, dominated by a 1.20–1.10 Ga population interpreted to be sourced from coeval magmatic rocks within the Tieshajie Complex itself. The abundant Archean and Paleoproterozoic detrital zircons are well-matched with magmatic records from the Eastern Yangtze Block, suggesting a Yangtze Block affinity of the Lower Tieshajie Subgroup. This implies that the surface boundary between the Yangtze and Cathaysia blocks is located to the south of the Lower Tieshajie Subgroup, probably in between the two parts of the Tieshajie Group. Age peaks of detrital zircons at 2.85–2.78 Ga, 2.68 Ga, and 2.50 Ga, combined with regional data, suggest episodic magmatism involved both crustal growth and reworking during the late Archean in the Jiangnan Orogen and adjacent areas of the Eastern Yangtze Block, while the 2.10–1.80 Ga peak corresponds to significant reworking of pre-existing crust related to the early assembly of the Nuna (Columbia) Supercontinent. Regional correlations based on detrital zircon age spectra and tectono-magmatic histories show similarities between the Yangtze Block and North India, suggesting the two continents were likely in spatial proximity at least during the late Mesoproterozoic to Neoproterozoic time.
Lamina structure, a typical feature of shale, has significant implications for hydrocarbon generation, shale oil and gas reservoir evaluation, and palaeoenvironmental studies. In this study, we conducted a high-resolution astronomical analysis of shale strata from the Kongdian Formation in the Cangdong Sag, Bohai Bay Basin, China, and performed macroscopic and microscopic textural characterization of core samples. The time series analysis of the G108-8 Well indicates that stratigraphic cycles of 113.2–25.3 m, 12.7–7.8 m, 4.7–2.7 m, and 2.3–1.3 m are controlled by long eccentricity, short eccentricity, obliquity, and precession, respectively. The sedimentary accumulation rate (SAR) is estimated to be approximately 20.3 cm/kyr. The core description reveals that Ek2 primarily consists of laminated shale with individual laminae less than 1 cm in thickness. Using a polarizing microscope, the average thickness of a single lamina is approximately 250 μm, with most laminae being less than 400 μm. We constructed a time-depth model for lacustrine laminated sediments and compared it with other ancient lacustrine strata and modern lakes. The sediment accumulation rate of ancient lacustrine strata ranges from 1.3 to 20.3 cm/kyr. The sedimentation rate of shale and the thickness distribution of individual laminae provide evidence for the annual nature of the lamina couplets. Finally, we propose a simplified model to illustrate the sedimentation process, emphasizing the record of laminated sediments in semi-deep to deep facies. Our results contribute to the understanding of lacustrine sedimentary processes, laminated sedimentary records, organic matter enrichment processes, palaeoenvironments, and their potential relationships.
We report unearthing the first silicate-type (S-type) lunar Antarctic micrometeorites (AMM) spherule and another spherule with a refractory chondritic phase. The lunar spherule is made of Augite with minor Ni magnetite (<1 wt.%), in contrast to other known cosmic spherules. The Augite’s minor oxide range in the spherule are as follows: Wo37-41En25-27Fs34-36, Al2O3: 0.7–1 wt.%, Cr2O3: 0.01–0.06 wt.%, MnO: 0.32–0.39 wt.% and TiO2: 0.03–0.09 wt.%. The lunar spherule’s chemical characteristics indicate that it originated from very low Ti lunar basalt (VLT) mare basalts. Chondritic diopside (Wo46-47En50-47Fs5-6, Al2O3: 1.7–1.6 wt.%, Cr2O3: 0.6–0.63 wt.%, MnO: 0.2–0.4 wt.%, and TiO2: 0.0–0.02 wt.%) makes up the refractory phase in the second spherule. The chemical composition of diopside is indistinct from those of calcium aluminium inclusion (CAIs) found in both ordinary and carbonaceous chondrites. Our finding reveals that micron-sized lunar impact debris can potentially reach the Earth’s surface, similar to the earliest formed nebulae solid component.
Small-scale lithospheric terranes (microplates) are important building-blocks of continental accretion but their presence is often obscured by subsequent plate-margin deformation events and by younger volcano-sedimentary covers. The geological fabric of the eastern Anatolian-Caucasian region results from the sequential accretion of lithospheric terranes against the southwestern continental margin of the Eurasian plate. Widespread sedimentary and volcanic covers conceal some of the principal tectonic boundaries in the region, and major uncertainties persist as to the number and extent of the various terranes.
Rare-earth elements (REEs) are on the critical minerals list in multiple countries due to their application in renewable technologies, electromobility, and defence. A key exploration focus is on clay-hosted REE deposits, which are reported to have a higher proportion of heavy REEs (e.g. Tb and Dy) relative to light REEs. Previous studies have focused on ionic clay-hosted REE deposits in South China and Madagascar; however, little is known about the mineralogy and economic viability of clay-hosted REE projects in Australia. This study provides the first overview of current exploration activities in relation to clay-hosted REE projects in Australia and presents microanalytical data to characterise the distribution of REE-bearing minerals and guide metallurgical processing pathways, as well as mineral system criteria to inform exploration targeting. Our review identified 91 clay-hosted REE projects in Australia, most of which are in the Yilgarn Craton, Albany-Fraser Orogen and the Gawler Craton. Sixteen mineral resource estimates have been completed that have an average grade and tonnage of 971 ppm total rare-earth oxide (TREO) and 145 million tonnes (Mt) across all resources. This study identified monazite, bastnäsite, allanite, zircon, and apatite as the main REE sources in granitic-to-mafic protoliths. These are partially broken-down during weathering resulting in the formation of secondary REE minerals including rhabdophane, bastnäsite, aluminium phosphate sulphate (APS) group minerals, and cerianite. The most significant finding is that the REE budget of Australian clay-hosted REE deposits is dominated by the primary and secondary REE minerals accompanied by a minor ionic proportion. However, some deposits in South Australia, Queensland, and Tasmania yield a higher ionic proportion of >40%. Accordingly, the mineral system model for the majority of Australian projects differs from ionic deposits located in South China due to contrasting exogenic (surface processes) and endogenic (geological) factors, particularly within the Yilgarn Craton, and it remains unclear whether emerging projects within Australia host economic and extractable REEs.
Snowfall is the primary form of cold-season precipitation over the Tibetan Plateau (TP), crucial for the maintenance of glaciers and snow cover, affecting regional climates and water resources availability. Through an integrative analysis of observations, numerical simulations, and statistical analyses, we found that the spatiotemporal distribution of snowfall across the TP is significantly influenced by black carbon (BC) aerosols from South Asia and the TP. BC affects the snowfall process through multiple mechanisms. Specifically, BC significantly raises atmospheric temperature over the TP, thereby reducing snowfall, particularly in the central TP during autumn, with reductions reaching approximately − 9 mm water equivalent month−1. Moreover, BC enhances cold-season moisture transport from the Bay of Bengal, increasing moisture flux in the southeastern TP and thereby augmenting snowfall in that area by up to 5 mm water equivalent month−1. This study elucidates the complex impact of BC on the spatial–temporal snowfall patterns across the TP and provides important insights into the sustainable development of water resources in the region amid ongoing climate change.
Lead (Pb) isotopes can provide key information to address fundamental geologic problems related to the formation and evolution of rocky planets. The Pb isotope system supports a diversity of applications, as it provides access to information on magma sources as well as geologic age. Consequently, a wide range of analytical techniques, data validation and interpretation strategies have been advanced across a range of Pb isotope studies. Given the multiple different Pb isotope pairs, reflecting different decay rates and ultimate parental isotope concentrations, Pb isotopes have been viewed as one of the more challenging isotope systems to comprehend. Here we provide an overview of the various analytical and interpretative approaches, for this system, and highlight their respective strengths in the context of applications, such as magma source tracking and model age determination. A discussion of different methods to determine magma source parameters (e.g., U/Pb ratio and model age) is presented, along with recommendations for data validation and reporting. A checklist for recommended data and metadata to report for Pb isotopes is provided. The aim of this contribution is to provide a framework that enables a robust interpretation of Pb isotope signatures, promoting data transparency and comparison across different analytical approaches.
Precambrian cratons are archives of several precious metallic deposits that significantly contribute to our planet’s resources and habitability and also provide key information on plate tectonics on Earth. The North China Craton (NCC) preserves important records of Neoarchean to Paleoproterozoic tectonic processes and associated episodes of metallogenic pulses that generated five major types of mineral deposits including banded iron formations (BIFs), volcanogenic massive sulfide (VMS) Cu–Pb–Zn deposits, orogenic Au deposits, magmatic sulfide Cu-Ni deposits and porphyry Cu deposits. These deposits are distributed in Neoarchean granite-greenstone belts and Paleoproterozoic orogenic belts, and show dominant mineralization ages of 2.6–2.5 Ga and two subordinate age groups of 2.7–2.6 Ga and 2.3–1.95 Ga. The Neoarchean metallogenic events generated BIFs, VMSs, Au and magmatic sulfide Cu-Ni deposits and the tectonic framework correlates with the microblock amalgamation and plate subduction possibly also aided by mantle plumes. The BIFs representing the dominant mineral deposits in Neoarchean are mainly Algoma-type with few examples of Superior-type. Meta-basaltic rocks associated with the Algoma-type BIF deposits in the granite-greenstone belts of the NCC display highly variable trace element compositions and LREE-depleted and LREE-enriched. The REE distribution patterns and high field-strength element characteristics of meta-basaltic rocks suggest the formation of BIF and VMS deposits in mid-ocean ridge, island arc and back-arc settings. The formation of VMS, Au and magmatic Cu-Ni deposits correspond to plate subduction and collision in a convergent continental margin setting during the late Neoarchean. The Paleoproterozoic deposits are represented by BIFs and porphyry Cu deposits. The Paleoproterozoic BIFs and meta-basaltic rocks correspond to magmatic-hydrothermal activities in passive continental margin or island arc settings, whereas the porphyry Cu deposits were formed in an extensional environment, corresponding to the Paleoproterozoic subduction-rifting events in the Trans-North China Orogen. The variation of δ56Fe, Ce anomalies and Y/Ho ratios in BIFs from Neoarchean to Paleoproterozoic indicate the initial increase of oxygen in late Neoarchean and the change of ambient marine environment from anoxic to oxic during the Great Oxidation Event. The multi-stage Neoarchean to Paleoproterozoic metallogenic systems of the NCC were intrinsically linked to the plate subduction along with arc-plume interaction and rifting-subduction-collision activities. The contemporaneous increasing in weathering of exposed continental crust due to plate subduction potentially controlled the atmosphere-hydrosphere oxidation state and formation of BIF deposits in the NCC.
The southwestern region of the Delhi-National Capital Region (NCR) experiences sporadic micro (M ≤ 3.0) and occasional small (M > 3.0) earthquakes with a seasonal influence. This study integrates remote sensing and seismological data to elucidate the seismotectonic scenario and identify potential unmapped faults. Analysis of DEM data (Cartoset) reveals numerous multidirectional minor faults, some coincident or conjugate to known major faults. Earthquake epicentres spatially correlate with several of these delineated faults. Fault plane solutions suggest a transition from central normal faulting to peripheral thrust faulting. Moment tensor decomposition indicates dominant double-couple mechanisms with significant non-double-couple components for earthquakes ranging from Mw 2.5 to 4.4. A major variation in principal stress orientation is apparent between the eastern and western regions of the study area. Stress inversion reveals a NW-SE shortening direction and unusual principal axis plunges, suggesting a rare “odd” or “unknown” faulting regime. These findings suggest ongoing rifting in the eastern Alwar basin may be inducing thrusting in the surrounding region along pre-existing Aravalli-Delhi fold belt thrusts. Seismogenesis likely results from a complex interplay of faulting, regional tectonics, and fluid interaction. This study highlights the value of a multidisciplinary approach for unravelling the intricacies of seismotectonic in low-to-moderate seismicity regions, with varying strengths due to diverse structural heterogeneity associated with mapped or unmapped (hidden) faults, which have been delineated in this study, as an additional information for assessing seismic hazard potential for Delhi-NCR.
The Jinyinshan-Huangdi′nao Li deposit (12,000 t Li2O @ 0.60%) was recently discovered in southern Hubei Province, South China. This deposit is divided into two ore sections, namely, Jinyinshan (0.24–1.32 wt.% Li2O) and Huangdi′nao (0.20–0.47 wt.% Li2O). The dominant Li-bearing phase and mechanism for Li enrichment remain unclear. Herein, a comprehensive study of ore geology, mineralogy and geochemistry is conducted. Field and petrographic investigations revealed that Li mineralization in the deposit was fault-controlled and that the altered metasedimentary rocks and hydrothermal veins with intensive Li mineralization contained high abundances of Li-rich clay minerals. Whole-rock XRD and in situ analyses of SEM-EDS, EMPA and LA-ICP-MS of clay minerals reveal that cookeite (0.99–2.80 wt.% Li2O) is the dominant Li-bearing phase, with subordinate illite (0.02–0.57 wt.% Li2O). The widespread replacement of Li-enriched illite by cookeite combined with the compositional continuum suggests that cookeite was likely formed by the hydrothermal replacement of illite at a temperature of 240–270 °C, as constrained by chlorite geothermometry (with average temperatures of 254 ± 2 °C in Jinyinshan and 259 ± 2 °C in Huangdi′nao). Since metasedimentary rocks of the Neoproterozoic Lengjiaxi Group in the deposit with variable Li anomalies host abundant Li-rich illite, Li mineralization was inferred to have occurred via hydrothermal metasomatism of these clay-rich clastic rocks. The hydrothermal fluids may have been driven by a deep magmatic heat source, as evidenced by previously reported U-Pb dating of apatite from the clay-Li ore, similar to the age of the Mufushan granitic batholith in the south, both of which are Early Cretaceous. The deep-sourced hydrothermal fluids caused the mobilization, migration and reprecipitation of Li as Li-rich clays along the fault zones. This mechanism of Li mineralization is different from existing models for clay-Li deposits worldwide, and this deposit can be classified as a new type, namely, fault-controlled hydrothermal metasomatic clay-Li deposit. Similar deposits are highly prospective both regionally and worldwide.
Continental lithosphere thickness significantly influences Earth’s tectonic style, the stabilization of cratons, the compositions of intraplate volcanic rocks, and specific types of metallogenesis. Although the Archean cratons currently boast the thickest lithosphere among Earth’s continents, the evolution of its thickness throughout geological history remains inadequately comprehended. Intraplate small-volume volcanoes, typical products of magmatic activities within continents with thick lithosphere on the modern Earth, were rarely observed until the early Paleoproterozoic, possibly due to the high mantle temperature and insufficient thickness of the continental lithosphere. Here we show that the modern intraplate continental basalts exhibit distinctive signatures of both elevated Nb/Ta and Dy/Yb ratios, setting them apart from basalts found in arc, rift, and plume settings. Our statistical analysis of a geochemical database of basalts worldwide spanning the past 3.5 billion years indicates that modern-like intraplate continental basalts have become extensive since ca. 2.2 Ga. We attribute the emergence of intracontinental basalts to a lithospheric thickening event within the Archean craton continents, resulting from horizontal compression of the lithosphere during the assembly of the Nuna supercontinent.
The southeastern Tibetan Plateau (SETP) plays a pivotal role in accommodating the crustal deformation between the complex Tibet Plateau and the South China Block during the Cenozoic associated with the India-Asia Convergence. In this study, we establish a high-resolution 3-D lithospheric structure model of the SETP through joint inversion of observable multi-geophysical data, to understand its Cenozoic progressive deformation processes, deep seismotectonic environment, as well as regional geodynamic mechanism. We identify two low-density zones within the mid-lower crust that are separated by a pronounced high-density body beneath the inner zone of the Emeishan Large Igneous Province (ELIP). We also image an interconnected channel flow in the lower crust beneath the SETP. To further confirm the relationship between Cenozoic deformation propagation and deep lithospheric architecture, we adopt a holistic perspective from joint inversion of observable multi-geophysical data, coupled with integrated analysis on geometric-kinematic characteristics of major strike-slip fault zones and regional tectonics in the SETP. The results show that the mechanically weak mid-lower crust of the SETP is characterized by low effective elastic thickness (Te), high heat flow, low-density/velocity and low-viscosity, which might accommodate the ductile flow and provide an important channel for the lateral extrusion of crustal materials from the Tibetan Plateau, and ultimately contribute to the episodic lithospheric deformation of the SETP. We trace three main phases of deformation within the SETP during the Cenozoic: the Eocene-early Oligocene latitudinal crustal shortening and thickening, the late Oligocene-early Miocene clockwise rotation and lateral extrusion along major strike-slip faults, and the mid-late Miocene lower crustal flow accompanied with regional kinematic reversal. The lithospheric deformation, the invasion of fluids and the upwelling of deep molten materials are conducive to strain accumulation, which might also explain the occurrence of large earthquakes. Geodynamically, we consider that both the spatio-temporal variance of convergent rates, subduction angle, and processes of the India-Asia Convergence may be associated with episodic crustal deformation and intense seismicity in the SETP. The aqueous fluids in the weak mid-lower crust may have propagated outward due to the long-term gravitational driving forces and contributed to the lithospheric deformation and seismicity of the SETP. Furthermore, the retreat of the subducted Indian slab as well as the rollback and back-arc spreading of the western Pacific Plate also provided favorable conditions for the eastward extrusion of the Tibetan Plateau.
Establishing the type and position of plate boundaries is crucial for paleogeographic reconstructions. The northern margin of Gondwana (NMG) is inferred to have been a convergent, Andean-style, plate margin for much the late Neoproterozoic to early Paleozoic (i.e., the Avalonian-Cadomian Orogen), based largely on the presence of igneous rocks with arc-related geochemical affinities. However, a major segment of the margin that fringed the Arabian Plate includes bimodal Ediacaran–middle Cambrian (ca. 600–500 Ma) igneous rocks, more typical of continental rift settings, which has led to ambiguous and contradictory interpretations of magma tectonogenesis. Here, we employ an alternative approach to investigate the tectonic setting of the NMG by studying the evolution of sedimentary basins that developed in Iran, Anatolia, and the Arabian Plate simultaneously with the ca. 600–500 Ma magmatism. The Ediacaran–middle Cambrian successions in this segment of the NMG consist of laterally continuous siliciclastic and carbonate sequences, which have been broadly correlated across the region. The consistent northward and eastward paleocurrent directions and decrease in clastic sediment grain-size from proximal (the Arabian Plate) to distal (Iran and Anatolia) successions suggest a northward and eastward deepening basin with relatively flat topography. The new detrital zircon (n = 2870) and apatite (n = 1178) U-Pb ages from the Ediacaran–middle Cambrian siliciclastic strata of Iran are mostly older than 600 Ma. Detrital apatite trace element compositions indicate that most grains are sourced from I-type granitoids and mafic igneous rocks, low- and high-grade metamorphic rocks, with a minority from ultramafic rocks. Together with published detrital zircon U-Pb age data from correlative strata in Anatolia and the Arabian Plate, these data suggest the pre-existing Arabian-Nubian Shield as the main source. Importantly, detrital zircon and apatite grains with ages < 600 Ma are rare in these strata, suggesting that they received little input from contemporaneous Ediacaran–middle Cambrian (ca. 600–500 Ma) igneous rocks. We suggest that the very small sediment contribution from the ca. 600–500 Ma igneous rocks argues against the tectonic model that considers the development of a large Andean-style magmatic arc at this segment of the NMG. Integrating these constraints from the sedimentary record with geochemical data from the ca. 600–500 Ma igneous rocks in Iran and Anatolia favors an extensional continental margin setting that may be related to escape tectonics or post-collisional relaxation during Ediacaran–Cambrian following Gondwana assembly.
Middle and heavy rare earth elements and yttrium (MHREYs) are critical to the high-tech and green-energy industries, generating tremendous supply risk in recent decades. Recently, sedimentary phosphorites have been identified as a new resource for MHREYs. The Early Cambrian is considered one of the critical large-scale phosphorus-forming periods in China and globally. During this period, widespread large-scale phosphorites mainly occurred at shelf, while small-scale phosphate concretions predominantly existed in near-slope settings on the Yangtze Block, South China. However, multi controls for ore-forming mechanism of extraordinary REYs enrichment in phosphorites have not been well constrained, limiting the understanding of the formation of large-scale phosphorites at shelf. To better understand the REYs enrichment in phosphorite, the REYs-rich Kunyang phosphorite, the largest phosphorite in shelf environment on the Yangtze Block, was investigated through mineralogy, in-situ geochemistry of major and trace elements in francolites. Based on the mineral characteristics, four types of phosphorite and four types of wall rocks were divided, which can be grouped into high-REYs (435–717 ppm) and low-REYs (224–282 ppm) categories. Comparing the geochemical characteristics of high-REYs and low-REYs groups, multi-mechanisms of REYs enrichment can be supposed. Frequent Fe redox cycling and related suboxic conditions may be responsible for the extraordinary REYs enrichment in phosphorites. In high-energy hydrodynamic systems with a low sedimentation rate, prolonged deposition of francolite enhanced the effects of adsorption and substitution in the early and late diagenetic stages, respectively, significantly increasing REYs uptake. Moreover, in the inner-shelf environment, wave fluctuations and storm effects are significant, leading to extensive diagenetic reworking, which form extremely high REYs contents in the altered rims of francolite. The negative Eu anomalies in the high-REYs group also indicate a positive influence of porewater on REYs enrichment. Regarding the sources of REYs, both seawater and terrigenous detrital material contribute to REYs in phosphorite at the shelf environment. The sedimentary high-REYs group indicate that terrigenous detrital material may enhance REYs content in seawater, which is then transferred to francolite during diagenesis. Consequently, multiple mechanisms controlled the REYs enrichment, leading to the formation of large-scale phosphorite in the inner-shelf.
Landslide susceptibility mapping (LSM) assists planners, local administrations, and decision-makers in preventing, mitigating and managing associated risks. This study proposes a novel DES-based framework that effectively captures the spatial developmental patterns of different landslide types, leading to higher precision LSM. The Wanzhou district (administrative division) of Chongqing Province, southwestern China, was selected as the test area, encompassing 881 landslides classified into rockfalls, reservoir-affected (RA) landslides, and non-reservoir-affected (NRA) landslides. Subsequently, three inventory maps and sixteen environment factors were used as inputs, with multicollinearity and importance analyses used to select the best factor combination for three types of landslides. Finally, the susceptibilities of rockfalls, RA and NRA landslides were combined by six combination strategies: Maximum, Mean, Probability, Voting, Stacking, and Dynamic Ensemble Selection (DES) models, and the optimal strategy was identified by area under the receiver operating characteristic curves (AUC), confusion matrix, and landslide distribution statistic. For LSM of individual landslide types, ResNet consistently outperformed traditional machine learning models, achieving testing AUC values of 0.8925, 0.9427, and 0.6754 for rockfalls, RA, and NRA landslides, respectively. The evaluation of the combination strategies revealed that the DES model achieved the highest testing AUC value of 0.8779, followed by Stacking (0.8728), Maximum (0.8704), Probability (0.8669), and Voting (0.8653), whereas the widely-used Mean method performed the worst (0.8503), even lower than the non-classified LSM (0.8587). The findings offer a robust approach for mitigating future landslide risks and minimizing their adverse impacts, providing valuable insights for geohazard management and decision-making.
Large igneous provinces (LIPs), a critical area in Earth science, are closely related to paleoenvironmental evolution and biodiversity. The Permian Tarim large igneous province (TLIP) provides an ideal laboratory for correlational research. Previous reports show that the TLIP formed ∼300–262 Ma. Based on igneous lithology and the upper limit of single magmatic activity (<5 Ma), the TLIP can be divided into five main magmatic episodes. Core logging, seismic sections, lithofacies observations, and in-situ calcite U-Pb dating indicate diabase intrusions and a hydrothermal upwelling event (∼295.9–273 Ma) resulted from TLIP magmatic activity. The results indicate that polycyclic aromatic compounds (PACs) in oil are powerful proxies of magmatic intrusion and hydrothermal activity in the Permian TLIP. The existing diabase intrusion (EDI) samples show a higher concentration of high-molecular-weight (HMW) PACs (≥5-ring PACs) and greater combustion-derived PAC ratios. The distribution coupling between the diabase intrusion and PACs indicates that the HMW PACs are mainly derived from the cycloaddition reactions by the pyrogenic source (i.e., diabase intrusion). The conversion of phenanthrene (Phe), biphenyl (Bp), and dibenzothiophene (DBT) series compounds indicates that the oil is altered by hydrothermal activity. The hydrogenium and sulfur carried by the hydrothermal upwelling process promote the heteroatom incorporation of PACs. The cycloaddition and heteroatom incorporation reactions of PACs during the formation of LIPs offer a new perspective for evaluating their impact. PACs serve as effective proxies for LIPs and may also contribute to biological crises associated with LIPs.
Lithium (Li) in geothermal waters along the India–Asia continental convergent margin is a potential Li resource and plays an important role in the Li budget and Li isotopic composition (δ7Li) of rivers and oceans. However, its origins and behavior remain unclear. Here, we systematically investigated the δ7Li, water (δ18O and δ2H) and helium (3He/4He) isotopes of 21 geothermal water samples as well as a series of shallow groundwater and river water samples from southern Tibet and the Himalayas. The δ7Li values of geothermal waters vary from +1.0‰ to +14.3‰ and are negatively correlated with the Li concentration (0.006–35.0 mg/L). For geothermal water with Li concentrations >5 mg/L, Li is sourced mainly from magmatic fluids exsolving from granitic magma chambers in the crust rather than the mantle, with contributions of 49.5% ± 3.2% to 85.5% ± 1.0%. The δ7Li values of these Li-rich geothermal waters are relatively homogeneous and comparable to those of bulk granitic rocks. They are mainly controlled by the Li isotopic compositions of granitic magmatic fluids (−2.6‰ to +5.6‰), and the dissolution of primary minerals and the precipitation of secondary minerals with minimal Li isotopic fractionation during high-temperature (174 ± 5 °C to 315 ± 6 °C) water–granite interactions at deep geothermal reservoirs (4.4–7.9 km). For geothermal waters with Li concentrations <5 mg/L, Li originates primarily from water–granitic rock interactions (dominated by biotite dissolution) at 106 ± 3 °C to 207 ± 10 °C, contributing approximately 85% ± 16% of the total Li. An integrated dissolution–precipitation–mixing model suggests that high δ7Li values in Li-depleted samples result from preferential incorporation of 6Li into secondary minerals at lower reservoir temperatures within shallower reservoirs (2.7–5.2 km) and mixing of shallow groundwater during the ascent of geothermal waters. This study provides new insights into the fluid geochemistry of crustal granitic magma chambers and highlights that Li-rich geothermal waters in Tibet are controlled by the existence of crustal granitic magma chambers and the scale of faults.
The magmatic arcs in the north-west region of Pakistan comprises of numerous volcanic and plutonic bodies of different ages and compositions evolved during the subduction of the Neo- Tethys Ocean under the Eurasian supercontinent. This study focusses on the examination of the granitoids of the Kohistan batholith (a part of Kohistan-Ladakh Island Arc; KLIA) and the Khunjerab pluton, concentrating on their petrological traits, mineral chemistry, in-situ zircon U-Pb geochronology, and whole-rock major and trace element geochemistry. According to zircon U-Pb dating, the Kohistan batholith granitoid was emplaced around 91.7 ± 0.3 Ma, while zircons of the Khunjerab pluton yield ages of 106.4 ± 0.4 Ma and 106.4 ± 1.0 Ma. All the samples from both magmatic units have calcic to calc-alkaline (Na2O + K2O: 3.6–10.6 wt.% and SiO2: 60–73 wt.%), metaluminous to peraluminous properties (Aluminum Saturation Index (ASI): 0.9–1.2). Notably, Nb, Ta, and Ti show depletion, while large ion lithophile elements like Cs, Rb, and K have been enriched. Additionally, we find that SiO2 and P2O5 have a negative correlation while Rb and Th have a positive correlation, which confirm an I-type arc magmatism. Together with the published literature, TEM analysis, and thermal modelling, our zircon U-Pb results point to a period of continuous magmatic activity from the Late Jurassic to the Late Cretaceous (between 150 Ma and 91 Ma) in the Kohistan Island arc region while the Khunjerab pluton (part of Karakorum block/Eurasian plate) experienced widespread magmatism around 120 Ma to 106 Ma. With SiO2 concentrations ranging from 67.5–73.3 wt.% and 60–71.4 wt.% and relatively low alkali (Na2O + K2O) contents between 3.6–10.6 wt.% and 5.1–7.4 wt.% in the Kohistan batholith and Khunjerab pluton respectively, showing clear signs of acidity. The whole rock as well as the mineral geochemical analysis and the elevated water contents (8–10 wt.% and 3.1–3.5 wt.%) inferred from amphibole and biotite chemistry respectively, indicates that the Kohistan batholith was most likely formed through partial melting of a (hydrous) magma originating from a more or less altered metasomatized mantle wedge. Likewise, the Khunjerab pluton whole rock geochemistry also indicates its origin through partial melting of magma originating from an altered metasomatized mantle wedge. This study also shows that both units are not only different in terms of the nature of magmatism but also in terms of their ages i.e., continental arc magmatism occurred in the Khunjerab (Karakoram) block in the middle Cretaceous (106 Ma) while island arc magmatism occurred on the Kohistan side in the late Cretaceous (91 Ma). Further, this study also investigate why multi-grain U-Pb zircon dating is necessary for studying magmatic rocks by using transmission electron microscopy.
A growing trend in environmental contamination has highlighted the need for greater access to green technologies and clean energy to alleviate environmental stress. This study seeks to quantify the impact of climate mitigation technologies, particularly those related to environmental technology, on environmental quality and economic development. The relationship between environment-related technologies, disaggregated energy use, carbon dioxide emissions, and the stringency of environmental policies was analyzed using Westerlund co-integration, FGLS, and Granger causality techniques across 19 member countries of the Organization for Economic Co-operation and Development (OECD). The findings show that an increase in fossil fuel use leads to a rise in carbon emissions. Similarly, the use of renewable energy also contributes to higher carbon emissions, while environment-related technologies have a positive impact on environmental quality. In contrast, stricter environmental policies have a negative effect on carbon dioxide emissions. A one-way causality was identified, with environment-related technologies, renewable energy adoption, and environmental policy stringency influencing carbon dioxide emissions, rather than being influenced by them. These findings underscore the significance of environment-related technology in enhancing both environmental quality and economic productivity. Policymakers are encouraged to focus on allocating resources for research, establishing robust regulatory frameworks, fostering collaboration, promoting education and awareness, and providing support for sectors transitioning toward climate change mitigation technologies.
Polystyrene nanoplastics (PS-NPs) and 3,3′,4,4′-tetrachlorobiphenyl (PCB77) are common pollutants in freshwater aquatic environments. To investigate the separate and combined toxicity of these two pollutants on the freshwater blunt snout bream (Megalobrama amblycephala), 270 juveniles were randomly assigned to six exposure treatments: the control group, CT (free of PS-NPs and PCB77), three single exposure groups, PS-L (0.2 mg/L PS-NPs), PS-H (2 mg/L PS-NPs), PCB (0.01 mg/L PCB77), and two combined exposure groups, PP-L (0.2 mg/L PS-NPs + 0.01 mg/L PCB77) and PP-H (2 mg/L PS-NPs + 0.01 mg/L PCB77). After a seven-day exposure, the tissue histopathology, antioxidant capacity, inflammatory response, and gut microbiome composition of fish were analyzed. The results showed that tissue fluorescence intensity of PS-NPs increases as the exposure levels of PS-NPs increase, and the combined exposure groups exhibited higher fluorescence intensity compared to their single PS-NPs exposure groups. Histopathological analysis showed that the exposure groups exhibited varying degrees of damage to the intestinal tissue compared to the control group, with more severe damage observed in the combined exposure groups. Additionally, liver damage was evident in the PS-H, PP-L and PP-H groups. Furthermore, the highest catalase (CAT) activities and malondialdehyde (MDA) contents were found in the intestine and liver of fish in the PP-L and PP-H groups. The mRNA levels of inflammatory factors (il, il-1β, il-8, il-6, il-10, and tnf-α) were up-regulated in the PS-H, PP-L and PP-H groups compared to those of the CT group. In addition, remarkable alternations in the intestinal microbiome compositions were observed among the groups: the abundance of Verrucomicrobiome and Planctomycetota increased in all exposed groups compared to that of the control group, while the abundance of Actinobacteriota was significantly reduced in the exposure groups. Functional prediction of microbiota indicated that the amino acid and carbohydrate metabolism, as well as intestinal structure, were impaired in the PS-NPs and PCB77 exposure groups. The results suggested that the toxicity of PS-NPs on M. amblycephala including tissue injury, oxidative stress, and disturbance of intestinal microbiota, depends not only on concentration but also increases when co-exposed to PCB77. This finding raises concerns about the ecological safety in freshwater aquatic environments.
Growing evidence suggests that extensional/transtensional settings are favorable for the formation of tin deposits, yet the underlying geodynamic mechanism remains equivocal. The Pingna W-Sn deposit, found in the underexplored interior of the giant tin belt within the Youjiang Basin, South China, offers a unique opportunity to explore and better constrain the current geodynamic model for tin mineralization. This deposit, composed of NW- to NWN-striking vein swarms with W-Sn mineralization, is hosted in the Middle Triassic clastic rocks without igneous rocks near its mineralization. Structural analysis indicates that the Youjiang fold-and-fault belt and the ore-related structures in the Pingna deposit experienced five deformation phases (D1–D5). The pre-ore NE-striking compression (D1; σv = σ3) initiated fault-fracture meshes, followed by NE-striking extension (D2), while NW-striking compression (D3; σv = σ2) enhanced the vertical connectivity of the meshes. Syn-mineralization E-W extension (D4; σv = σ1) facilitated upward through-going flow and hydrothermal fluids infilled the meshes, forming a fault-vein system. The mineralized veins were cut across by post-ore WNW-striking oblique fault with sinistral and normal components (D5). The meshes dictated Sn-W orebodies localization. Hydrothermal veins formed in three stages: (I) muscovitization-bordered tin-dominated quartz vein swarms along the Pingna fault; (II) W-dominated lit-par-lit vein system; and (III) barren calcite veins crosscutting the former veins. The Pingna W-Sn mineralization formed during the Late Cretaceous as constrained by the cassiterite (Cst1) U-Pb age of 95.6 ± 2.4 Ma (2σ, MSWD = 1.2), muscovite (Ms1) 40Ar-39Ar plateau age of 93.9 ± 0.1 Ma (2σ, MSWD = 1.7), and molybdenite Re-Os age of 92.9 ± 1.2 Ma (2σ, MSWD = 0.3). Outward lateral zoning of the Sn-W mineralization, as well as associated muscovitization and silicification implies the epicenter of hydrothermal fluid is near the No. II vein swarm. Contemporaneous felsic dykes coupling with the inferred intrusions demonstrate that the Pingna deposit is a distal hydrothermal W-Sn deposit. The releasing bend of the NW-striking Pingna fault controlled the distribution of tin-dominated mineralization, while the anticlines controlled the tungsten-dominated mineralization. Our findings suggest that the localization and formation of the Pingna W-Sn veins were controlled by Late-Cretaceous regional transtensional stress field and polyphase deformation, rather than previously proposed local extension of the Youjiang Basin. The discovery of the Pingna W-Sn deposit highlights the interior of the Youjiang Basin as a promising area for tungsten-tin exploration.
Many aspects of the disassembly of Neoproterozoic supercontinent Rodinia remain poorly constrained. Current models for the breakup along western Laurentia (present coordinates) do not fully reconcile stratigraphic observations regarding the timing and mechanisms of continental rifting. Latest Neoproterozoic to Cambrian stratigraphic units exposed along the North American Cordillera from southwestern Canada to the southwestern United States contain Neoproterozoic and Cambrian zircons interpreted to be sourced from rift-related igneous rocks generated during the fragmentation of Rodinia. Two discrete magmatic episodes distinguished by a ca. 50 Myr period of apparent magmatic quiescence are identified using the detrital record: (1) Tonian and Cryogenian to earliest Ediacaran magmatism (mantle plume events followed by rifting); and (2) latest Ediacaran to late Cambrian magmatism. The detrital zircon record of the first episode supports a 660–650 Ma rift-to-drift transition followed by passive margin sedimentation of the upper Windermere Supergroup. After a period of apparent magmatic quiescence from 630–580 Ma, detrital zircon dates of 580–520 Ma from central-western Laurentia provide evidence for renewed rift magmatism preceding the initiation of the lower Paleozoic passive margin. These new U-Pb dates are used to present a refined model of Rodinia disassembly with improved timing constraints suggesting that its final breakup and the Sauk I transgression occurred ca. 520 Ma, in accordance with recent revisions to the timing of the Sauk transgressions in southwestern Laurentia.
Studies arising from literature reviews are important as they facilitate specific understanding about the use of the Sentinel-5P satellite developed by the European Space Agency (ESA) to detect the concentration levels of atmospheric pollutants on a global scale. The objective of this literature review is to analyze the application of the geospatial optics of the Sentinel-5P satellite; coupled with the Tropospheric Monitoring Instrument (TROPOMI) in the detection of NO2 and CO over the period beginning in May 2018 and lasting through May 2024. This was accomplished using manuscripts published in the ScienceDirect databases. The study employed the rigorous Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method, using the specific search term ‘sentinel TROPOMI satellite’, which yielded 555 results published between 2018 and 2024. Subsequently, 274 manuscripts were selected, and 85 were classified for analysis after a concise review. The Content Analysis Method (CAM) was used to understand the absolute frequency, with the use of the MAXQDA software (version 24.2.0) in this analysis. The purpose of using TROPOMI in the 85 manuscripts analyzed is significant. The manuscripts studied focused on air quality monitoring (30.1%), COVID-19 impact detection (24.3%), assessment of pollution sources (23.3%), support for decision makers (13.6%) and the development of methods and tools (8.7%). In this context, 38.5% of the examined studies focused on Asia, followed Europe (29.2%), North and South America (25.1%) and Africa (7.3%). TROPOMI data makes it possible to contribute to creating future government public policies on both the local and global scale.
