The Naoli River Basin (NRB), a pivotal agricultural production area in China, is poised to undergo substantial impacts on water resources due to projected climate and land use/cover (LULC) changes. Despite its significance in the context of China's expanding farmland construction in the NRB, there exists limited research on the potential repercussions of future shifts in runoff, soil water content (SWC), and evapotranspiration (ET) on crop productivity and water availability (both in terms of quantity and timing). This study employs future LULC maps and an ensemble of ten CMIP6 Global Climate Models (GCMs) across three scenarios to drive the well-calibrated distributed hydrological model, ESSI-3. The objective of present study is aimed on projecting hydrological consequences under climate and land use/land cover changes in near-term (2026–2050), middle-term (2051–2075), and far-term (2076–2100) future in comparison to the baseline period of 1990–2014. Results consistently indicate an increase trend in annual average ET, runoff, and SWC in the NRB across all three future periods under the three SSP scenarios. LULC changes emerge as the primary driver influencing regional hydrological processes in the near future. Notably, under high-emission scenarios, monthly runoff and SWC are projected to significantly increase in March but decrease in April during the middle and far future periods compared to the baseline. This shift is attributed to the anticipated warming of winter and spring, leading to a transition in peak snowmelt from April to March. Concurrently, the expansion of cropland intensifies crop evapotranspiration demand, potentially exacerbating water stress during the early stages of crop growth in April. The findings underscore the importance of addressing the substantial impacts of climate change and land use planning on regional water cycling processes. Early planning to mitigate water shortages during the initial stage of future crop growth is crucial for ensuring food security and managing water-related challenges in the NRB and neighboring mid-high latitude regions.
Coastal regions are highly susceptible to the effects of global warming, including rising atmospheric and sea surface temperatures, increased cyclone frequency, and sea level rise. Thus, it is imperative to examine coastal vulnerability to minimize the impact of multiple hazards and protect coastal resources, such as mangroves. Particularly in India studying the vulnerability of coastal zones of Andaman and Nicobar Islands which fall in seismic zone V is critical for conservation efforts. We conducted a vulnerability analysis of coastal zones impacted by the 2004 earthquake, causing varying degrees of ground upliftment and subsidence. We compared coastal vulnerability among sites that experienced uplift, no change, and subsidence (the southern portion). Our analysis utilized the Coastal and Mangrove Vulnerability Index (CVI and MVI) to measure and compare vulnerability in six zones distributed along uplift and subsidence gradient. High-resolution satellite imagery including WorldView-2, 3, and GeoEye-1 from year 2022 are utilized on this study. The CVI and MVI offers a good way to measure and compare vulnerabilities across sites and offer insights for better management. The CVI and MVI results indicate that approximately 34% of coastal grids and over 23% of mangrove grids across all zones are highly to extremely highly vulnerable. Subsided zones were found to be more vulnerable than uplifted zones. These findings suggest that large-scale natural disturbances such as tectonic displacement have the potential to impact coastal vegetation and mangrove cover can become even more vulnerable. In conclusion, our study emphasizes the importance of vulnerability analyses in coastal regions, especially in areas prone to seismic activity. Our findings have direct implications for conservation and restoration efforts and underscore the need for continued monitoring and mitigation efforts to safeguard coastal resources for long-term sustainability.
Shallow landslide initiation typically results from an interplay of dynamic triggering and preparatory conditions along with static predisposition factors. While data-driven methods for assessing landslide susceptibility or for establishing rainfall-triggering thresholds are prevalent, integrating spatio-temporal information for dynamic large-area landslide prediction remains a challenge. The main aim of this research is to generate a dynamic spatial landslide initiation model that operates at a daily scale and explicitly counteracts potential errors in the available landslide data. Unlike previous studies focusing on space–time landslide modelling, it places a strong emphasis on reducing the propagation of landslide data errors into the modelling results, while ensuring interpretable outcomes. It introduces also other noteworthy innovations, such as visualizing the final predictions as dynamic spatial thresholds linked to true positive rates and false alarm rates and by using animations for highlighting its application potential for hindcasting and scenario-building.
Data exploration, usually the first step in data analysis, is a useful method to tackle challenges caused by big geoscience data. It conducts quick analysis of data, investigates the patterns, and generates/refines research questions to guide advanced statistics and machine learning algorithms. The background of this work is the open mineral data provided by several sources, and the focus is different types of associations in mineral properties and occurrences. Researchers in mineralogy have been applying different techniques for exploring such associations. Although the explored associations can lead to new scientific insights that contribute to crystallography, mineralogy, and geochemistry, the exploration process is often daunting due to the wide range and complexity of factors involved. In this study, our purpose is implementing a visualization tool based on the adjacency matrix for a variety of datasets and testing its utility for quick exploration of association patterns in mineral data. Algorithms, software packages, and use cases have been developed to process a variety of mineral data. The results demonstrate the efficiency of adjacency matrix in real-world usage. All the developed works of this study are open source and open access.
Many studies propose a significant shift in the tectonic and paleogeographic evolution of the Andes in south-central Chile and Argentina during the Late Cretaceous. It has been proposed that the preceding Jurassic-Early Cretaceous extensional regime that resulted in a low-relief volcanic arc and the backarc Neuquén basin came to an end, giving way to shortening and Andean growth from the Late Cretaceous onward. Nevertheless, there are disagreements regarding the timing and nature of this transition to Andean orogenesis. To address these issues, we conducted geochronologic (U–Pb and 40Ar/39Ar), sedimentologic, and structural studies on Mesozoic-Cenozoic sedimentary and volcanic rocks in the Río Maule area (Principal Cordillera, Chile, 36°S). From our findings and prior analyses, we propose the following tectono-stratigraphic evolution of the region. (1) Marine deposition of the Tithonian-Hauterivian Baños del Flaco Formation took place in an extensional backarc basin. (2) After a ∼ 40 Myr hiatus, fluvial deposits of the Colimapu Formation and volcanic rocks of the Plan de los Yeuques Formation accumulated during the Cenomanian-Danian. Whereas the Colimapu Formation displays evidence of syndepositional shortening, the Plan de los Yeuques Formation exhibits synextensional growth strata. Contrary to other studies, our results suggest that the Chilean part of the Principal Cordillera was largely a zone of active deposition rather than an elevated fold-thrust belt during the Late Cretaceous. We propose that sedimentation occurred within a series of relatively stable intermontane subbasins generated by shortening, followed by extension. (3) After a ∼ 20 Myr hiatus, middle Eocene to early Miocene (Lutetian-Aquitanian) accumulation of a thick succession of andesitic lavas and minor clastic sediments of the Abanico Formation occurred in an intraarc extensional basin. (4) Finally, major shortening and uplift of previously deposited Mesozoic-Cenozoic rocks took place throughout the Neogene. This phase constituted the primary contractional deformation in the Andes of south-central Chile and Argentina. In terms of the transition to early Andean deformation, we propose that structural deformation did not generate a major, regional-scale fold-thrust belt during the late Albian-Santonian. Modest extension, tectonic quiescence, or low-magnitude shortening seem to have dominated during the early to middle Cenozoic.
The equatorial evergreen forests nourish the world's biodiversity hotspots and are considered the lungs of the Earth. However, their future survival is uncertain, due to anthropogenically increased carbon emissions and changes in the hydrological cycle. Understanding the changes in the hydrological cycle in the equatorial region due to an increase in carbon emission is of prime importance. The early Paleogene hyperthermal events are potential analogs to understand the consequences of high carbon emission on the hydrological cycle. In this communication, we quantify the terrestrial seasonal climate using the plant proxy and infer that during the Eocene Thermal Maximum 2 when atmospheric carbon dioxide concentration was > 1000 ppmv near the palaeo-equator (∼0.6°N), the rainfall decreased significantly, leading to the expansion of deciduous forests. This study raises important questions about the future survival of equatorial rainforests and biodiversity hotspots under increased carbon emissions.
Earthquakes pose significant risks globally, necessitating effective seismic risk mitigation strategies like earthquake early warning (EEW) systems. However, developing and optimizing such systems requires thoroughly understanding their internal procedures and coverage limitations. This study examines a deep-learning-based on-site EEW framework known as ROSERS (Real-time On-Site Estimation of Response Spectra) proposed by the authors, which constructs response spectra from early recorded ground motion waveforms at a target site. This study has three primary goals: (1) evaluating the effectiveness and applicability of ROSERS to subduction seismic sources; (2) providing a detailed interpretation of the trained deep neural network (DNN) and surrogate latent variables (LVs) implemented in ROSERS; and (3) analyzing the spatial efficacy of the framework to assess the coverage area of on-site EEW stations. ROSERS is retrained and tested on a dataset of around 11,000 unprocessed Japanese subduction ground motions. Goodness-of-fit testing shows that the ROSERS framework achieves good performance on this database, especially given the peculiarities of the subduction seismic environment. The trained DNN and LVs are then interpreted using game theory-based Shapley additive explanations to establish cause-effect relationships. Finally, the study explores the coverage area of ROSERS by training a novel spatial regression model that estimates the LVs using geographically weighted random forest and determining the radius of similarity. The results indicate that on-site predictions can be considered reliable within a 2–9 km radius, varying based on the magnitude and distance from the earthquake source. This information can assist end-users in strategically placing sensors, minimizing blind spots, and reducing errors from regional extrapolation.
The Middle Paleozoic tectonic evolution of the central Korean Peninsula (Gyeonggi Massif, Hongseong-Imjingang, and Okcheon zone of Okcheon Belts) remains controversial. Particularly, the occurrence of high-grade metamorphism and sedimentation need further examination. In this study, we conducted zircon U-Pb-rare earth element analyses from in the ultramafic-mafic complex in the central Korean Peninsula (Cheonan and Gapyeong areas) and the Paleozoic metasedimentary rocks in the Okcheon Zone of the Okcheon Belt to constrain the timing of maximum depositional and metamorphic ages. We also examined the metamorphic P-T-t path from garnet-bearing amphibolite in the central Korean Peninsula by pseudosection modeling and geothermobarometer. The results show that (i) some of the ultramafic-mafic complex and metasedimentary rocks in the central Korean Peninsula formed during the Middle Paleozoic (ca. 450–374 Ma); (ii) garnet-bearing amphibolite underwent successive metamorphism from amphibolite facies condition (7.5–8.0 kbar and 540–630 °C) at pre-peak stage to granulite facies condition (10.9–11.8 kbar and 740–820 °C) at peak stage, and then retrograded into amphibolite facies condition (5.7–7.7 kbar and 530–670 °C) along the clockwise P–T path during ca. 403–362 Ma. This and previous studies suggest that the central Korean Peninsula underwent subduction-related orogenic events during the Middle Paleozoic era, and it is well correlated to those of the orogenic events in the North Qinling belt.
Countries face the risk of natural resource curse because of making their economic growth excessively dependent on natural resources. Although excessive resource dependence causes such a risk, it is inevitable that resource-rich countries will need resource rent up to a certain level of economic maturity. On the other hand, transferring the wealth achieved after this maturity level to productive investment areas also reduces the resource dependency levels of countries. In this context, countries that capture the possible inverted U-shaped relationship between economic growth and resource dependence can escape the curse. Based on this, the aim of this research is to determine the validity of the Kuznets type relationship between resource dependence and economic growth for the first time in the literature. Nine nations that rely heavily on natural resources are used as a sample for this. The countries with a share of total resource rent in national revenue greater than 25% are taken into consideration throughout the selection process for these countries. Using novel panel data methodologies, the effects of capital accumulation, public spending, foreign direct investment, and economic growth on the dependence on natural resources is examined from 1993 to 2021. The results reveal that capital accumulation reduces resource dependency while foreign investments and government size increases it. In addition, the Resource-Based Kuznets curve concept is supported by empirical data demonstrating an inverted-U-shaped relationship between economic growth and resource dependence for these nations. The thresholds derived from the parameters show that Saudi Arabia and Kazakhstan are well beyond this cutoff. The Democratic Republic of the Congo and the Republic of the Congo, on the other hand, remain a long way from this threshold. Furthermore, Iraq, Mongolia, Iran, and Azerbaijan have national incomes that are close at the threshold.
Covered by erodible loess and affected by significant seasonal climate variations, chemical weathering in the Chinese Loess Plateau (abbreviated as CLP) has important effects on the hydrochemistry of the Yellow River and the global carbon cycle. However, chemical weathering processes in the CLP are still unclear. Based on 296 river water samples in the CLP in the different seasons, hydrochemistry, weathering processes, and their controlling factors were revealed. River waters in the CLP exhibited slightly alkalinity (pH = 8.4 ± 0.5) with much high total dissolved solids (TDS) values (691 ± 813 mg/L). The water types of river water in the CLP were primarily SO42− − Cl− − Na+, HCO3− − Ca2+ − Mg2+, and SO42− − Cl− − Ca2+ − Mg2+. According to the forward model, evaporite dissolution has the largest contribution (55.1% ± 0.2%) to riverine solutes in the CLP, then followed by carbonate weathering (35.6% ± 0.2%) and silicate weathering (6.5% ± 0.1%). For spatio-temporal variations, the contribution of evaporite dissolution in the CLP decreased from northwest to southeast with higher proportion in the dry season, carbonate weathering increased from northwest to southeast with a higher proportion in the wet season, and silicate weathering showed minor spatio-temporal variations. Ca2+ and Mg2+ were affected by carbonate precipitation and/or incongruent calcite dissolution, and about 50% of samples exhibited cation exchange reactions. The physical erosion rate in the CLP, which was 372 ± 293 t·km−2·yr−1, varied greatly and was greater than those of other worldwide rivers. Chemical weathering rates in the CLP showed an increasing trend southward. During the wet season, high runoff led to the release of evaporite and carbonate from loess, while the interfacial reaction kinetic limited the increase of the silicate weathering rates. The CO2 consumption budget by carbonate weathering (6.1 × 1010 mol/yr) and silicate weathering (1.6 × 1010 mol/yr) in the CLP accounted for 0.29% and 0.08% of the global carbon cycle, respectively. Meanwhile, the weathering proportion by sulfuric acids was relatively high with a CO2 release flux of 6.5 × 109 mol/yr. By compiling the data, we propose that the interfacial reaction kinetic and runoff control CO2 consumption rate by silicate and carbonate weathering, respectively. These results contribute to the understanding of modern weathering processes of loess in the CLP, thus helping to deduce the environmental and climatic evolution of the basin.
Economic growth has brought a global climate change into the spotlight, and CO2 emissions demonstrate significant challenges in reducing environmental shifts worldwide. Globally, the United States and China contribute the largest amount of CO2 emissions. The purpose of this study is to examine the relationship between different types of CO2 emissions and economic growth by using a modeling approach. We analyze total CO2 emissions, coal CO2 emissions, oil CO2 emissions, the global share of coal CO2 emissions, the global share of oil CO2 emissions, and economic growth. This study provides unique insights into how to simultaneously reduce CO2 emissions and sustain economic growth. A bootstrap autoregressive distributed lag (BARDL) simulation method is utilized to examine the long- and short-run effects of predictors on CO2 emissions. Coal CO2 emissions are found to have a significant positive effect on economic growth in the short run but a negative impact on economic growth over the long run in the United States. The United States needs to implement stronger measures to balance coal CO2 emissions with economic growth for sustainable development. In contrast, oil CO2 emissions have positive effect for China in both the long run and short run. Thus, China can continue to reduce CO2 emissions from oil while maintaining positive economic growth. The China's policies promoting cleaner energy alternatives can be adapted and implemented to maintain a balance between economic growth and carbon reduction. The study has valuable insights for policymakers seeking to balance economic growth with carbon reduction strategies. It emphasizes the need to better understand the complex relationship between CO2 emissions and economic growth.
The hydro-geochemistry and isotopic variations in groundwater, coupled with sediment geochemistry, were investigated in the Middle Gangetic Plain, India, to better understand the aquifer dynamics that influence the arsenic (As) evolution and mobilization. Eighty-four groundwater samples, thirteen River water samples, and two sediment cores (33 mbgl) were studied. The samples were analyzed for major ions and trace metals, including As and stable isotopic variability (δ2H, δ18O, and δ13C). The study area was categorized into older and younger alluvium based on existing geomorphological differences. Younger alluvium exhibits higher As enrichment in sediment and groundwater, ranging of 2.59–31.52 mg/kg and bdl to 0.62 mg/L. Groundwater samples were thermodynamically more stable with As(OH)3 species ranging from 88.5% to 91.4% and FeOOH from 69% to 81%, respectively. PHREEQC and mineralogical analysis suggested goethite and siderite act as a source and sink for As. However, statistical analysis suggested reductive dissolution as the primary mechanism for As mobilization in the study area. Spatio-temporal analysis revealed elevated concentrations of As in the central and northeastern regions of the study area. Stable isotope (δ2H and δ18O) analysis inferred active recharge conditions primarily driven by precipitation. The depleted d-excess value and enriched δ18O in the groundwater of younger alluvium indicate the effect of groundwater recharge with significant evaporation enrichment. Groundwater recharge potentially decreased the quantity of arsenic in groundwater, whereas evaporation enrichment increased it. Rainwater infiltration during recharge introduces oxygenated water into the aquifer, leading to changes in the redox conditions and facilitating biogeochemical reactions. The carbon isotope (δ13C) results suggest that high microbial activity in younger alluvium promotes As leaching from sediment into the groundwater.
Carbon isotopes have been used extensively in tracing the sources of oil. However, primary source facies and secondary alteration controls on oil isotopic compositions have not been well resolved, resulting in application uncertainties. A case study was undertaken for an alkaline lacustrine oil system in a lower Permian formation in the Junggar Basin, NW China. Results indicate that increasing maturity causes the carbon isotopic composition to become heavier for only short–middle-chain compounds, whereas source facies-related carbon assimilation controls the compositions of short-, middle-, and long-chain compounds. In particular, light-carbon assimilation during organic-matter degradation makes the isotopic composition lighter, whereas heavy carbon from the water mass makes it heavier. Accordingly, oils in this study area were divided into Type U and Type N oils based on individual compound carbon isotopic compositions, reflecting the difference in source facies in a highly saline and reducing stratified water environment. The results provide a better understanding of the controls on carbon isotopes in oil in sedimentary basins, reducing the uncertainty in oil–source correlation and addressing the origin of oil.
Mikir Hills region, which represents the eastern segment of the Assam-Meghalaya Gneissic Complex (AMGC) in northeast India, constitutes part of the Eastern Gondwana. The Mikir Hills preserves multiple metamorphic and magmatic events ranging from Early Mesoproterozoic to Early Cambrian. Out of these events, documenting the late Neoproterozoic to early Cambrian tectonothermal events is helpful in correlating the continental blocks of Eastern Gondwana. We present an integrated study involving field relations, petrology, P–T history and zircon-monazite geochronology of hitherto poorly studied pelitic and quartzo-feldspathic gneisses from the Mikir Hills region. These gneisses have experienced at least three deformation events (D1, D2 and D3) with dominant foliation indicated by ENE–WSW striking and shallow-moderately dipping (<40°) S2 gneissic foliation. The peak metamorphism in pelitic and quartzo-feldspathic gneisses is characterized by garnet(core)–K-feldspar–sillimanite–plagioclase–biotite–rutile–quartz–ilmenite–melt and garnet–plagioclase–K-feldspar–biotite–quartz–ilmenite–melt assemblages, respectively. The application of thermobarometric methods constrains the peak P–T conditions of 7.5–8.4 kbar at 674–778 °C and 6.7–7.4 kbar at 601–618 °C for pelitic and quartzo-feldspathic gneisses, respectively. These results are consistent with the values estimated using phase equilibria modelling and melt reintegration approach. The results of pseudosection modelling suggests a clockwise P–T path for pelitic gneisses involving migmatisation during peak metamorphism followed by near isothermal decompression from 8.0 to 8.6 kbar at 768–780 °C to 4.0–5.0 kbar at 720–765 °C. In contrast, quartzo-feldspathic gneisses preserved slightly lower peak P–T conditions at 3.8–4.6 kbar and 590–650 °C. The U–Pb zircon dating of migmatised pelitic and quartzo-feldspathic gneisses yielded concordant ages of 1647 ± 11 Ma and 1590 ± 7 Ma, respectively. These dates represent the inherited igneous protolith components, possibly equivalent to the Mesoproterozoic granulite facies metamorphism in the western AMGC. The rarely preserved cores of monazite in pelitic gneisses yielded an older population of 1058 ± 35 Ma, most likely representing a weak tectonic imprint associated with the amalgamation of India with Western Australia and East Antarctica in the Rodinia assembly. However, the majority of monazite grains in pelitic and quartzo-feldspathic gneisses show high Th/U ratios with ages between 496 ± 7 Ma and 467 ± 16 Ma, indicating the timing of migmatisation that is contemporary with voluminous ∼ 500 Ma granite magmatism in and around the Mikir Hills. The similarities in P–T–t histories estimated in this study (eastern AMGC) and those obtained from the Sonapahar-Umpretha region (central AMGC) confirm that these domains experienced common tectonometamorphic history during Pan-African orogeny. The dominance of Late Neoproterozoic migmatisation and magmatism in the Mikir Hills region indicate that the eastern AMGC represent an active convergent margin with Western Australia and East Antarctica and evolved as a hot orogen during the assembly of Western and Eastern Gondwana continental fragments.
The Neoarchean Storø Supracrustal Belt in SW Greenland comprises a sequence of mature quartzite, metapelite, amphibolite, and ultramafic rocks that underwent amphibolite facies metamorphism during the amalgamation of the Mesoarchean Akia Terrane and the Eoarchean Færingehavn Terrane. In this belt, tourmaline is found in a transition zone between ultramafic and metapelitic rocks, but also occurs as orbicules within the ultramafic rocks. These tourmaline orbicules hosted by ultramafic rocks are reported for the first time in the North Atlantic craton, thus indicating a unique formation mechanism. We conducted a comprehensive examination of the petrology, whole-rock and mineral chemistry, and oxygen isotope compositions from borehole samples in the Storø Supracrustal Belt, to elucidate the metasomatic events associated with the formation of the orbicular tourmalines. The Storø ultramafic rocks have high MgO, Cr, and Ni contents, with low abundances of REE and HFSE, and preserve a typical cumulate texture. These features are similar to those of ultramafic cumulates found in other Archean supracrustal belts, suggesting a cumulate origin for the Storø ultramafic rocks. Furthermore, the morphology and composition of the tourmaline orbicules within these cumulates indicate that they originated from melts with high boron and high water concentrations that infiltrated the ultramafic rocks. The main factor influencing the morphology of the tourmaline orbicules is the silicification of the ultramafic rocks, driven by their lower chemical potential of SiO2 compared to the surrounding rocks. This silicification process, in combination with compositional variations of cumulates during fractional crystallization, has contributed to the geochemical diversity observed in Archean ultramafic rocks. Thus, it is crucial to understand the effects of such selective metasomatism on Archean ultramafic rocks, as this will facilitate the extraction of original information preserved in the early rock record.
The trace element composition of zircon reveals information about the melt that they are derived from, as such, detrital zircon trace element compositions can be used to interrogate melt compositions, and thus the evolution of the continental crust in time and space. Here, we present a global database of detrital zircon compositions and use it to test whether average global trends for five common petrogenetic proxies truly represent secular changes in continental evolution. We demonstrate that the secular trend is broadly comparable across continental regions for Ti-in-zircon temperatures, but for other trace element ratios interrogated, secular trends are highly variable between continental regions. Because trace element ratios result from multiple petrologic variables, we argue that these petrogenetic proxies can be overinterpreted if projected to global geologic processes. In particular, we caution against the interpretation of crustal thickness from trace elements in zircon, and we argue that our results negate current hypotheses concerning secular changes in crustal thickness.
Kaapvaal lamproites (aka orangeites) are a group of volatile-rich (H2O, CO2), micaceous, ultrapotassic igneous rocks that are unique to the Kaapvaal craton in southern Africa. However, the composition of the melts that give rise to these rocks remains poorly understood due to overprinting effects of contamination by mantle and crustal material, volatile exsolution, fractional crystallisation and post-magmatic alteration. Consequently, this lack of reliable data on the initial composition of the Kaapvaal lamproite melts hampers our understanding of their source, petrogenesis and ascent mechanisms.
The c. 1000-m-thick pre-orogenic Devonian mainly metapelitic sequence of North Menorca Island shows a fairly complete stratigraphic succession. The rocks of this sequence indicate gradually increasing deeper marine conditions of sedimentation towards its uppermost levels. Furthermore, the obtained sedimentary characteristics resemble those related to a deep and narrow basin-associated deposit. Thin sills of Ti-augite-bearing alkaline gabbros occur within the Devonian sequence. The intensity of Variscan deformation increases downwards through the structure. According to the characteristics of the Devonian sequence and its location within the Variscan Orogen, a correlation with similar units located in the southern sectors of the Central Iberian Zone (Iberian Massif) is suggested. The Devonian metapelitic rocks have geochemical characteristics suggesting that they represent moderately recycled mature siliciclastic sediments, generated from erosion of distant source areas belonging to an upper continental crust. The relatively narrow range of variation observed in initial 143Nd/144Nd ratios supports a similar source for the Menorcan slates (0.51165–0.51182). However, a marked trend is observed in these isotope ratios, from lower values at the base of the stratigraphic column (minimum value of 0.511941) to higher values at the top (maximum value of 0.512131). The 147Sm/144Nd ratios vary between 0.1074 and 0.1238, within the range defined for siliciclastic rocks with felsic crustal provenance. The Nd model ages define a narrow range between 1496 Ma and 1754 Ma (Late Paleoproterozoic–Early Mesoproterozoic), and they are consistently younger up-section. These data rule out a provenance from the erosion of the West Africa Craton, as they are more compatible with a provenance from regions located in the Trans-Saharan Belt or Sahara Metacraton. The characteristics of the Menorcan Devonian sequence are compatible with its deposition in a narrow and deep peri-Gondwanan transtensional basin, generated to the south of an advancing Variscan orogenic wedge. Systematic variations in the Nd isotopic composition indicate the progressive and continuous denudation of increasingly more easterly North African sectors in a collisional context between Laurussia and Gondwana with a marked dextral component. These data must be interpreted in the sense that there was not a large oceanic domain during Devonian times to the south of Iberia, able to block the arrival of detrital material from North Africa. A large tract of the Paleo-Tethys Ocean would therefore not have existed during the Devonian south of Iberia. This ocean must therefore have had limited extent in this period towards the westernmost sectors. The Devonian peri-Gondwanan shelf was apparently continuous around Iberia. This platform was progressively affected by Variscan deformation advancing from north to south and incorporated into the Variscan orogenic wedge with the same vergence.
Mesozoic magmatic rocks occur widely in the South China Block and are generally interpreted as the manifestations of the subduction of the Paleo-Pacific oceanic lithosphere beneath Asia. Subduction-driven magmatism in southeast (SE) China continued from the Late Permian through the Late Cretaceous with an inferred lull between 125 Ma and 115 Ma that is known in the literature as the Cretaceous “magmatic quiescence”. We report in-situ zircon U–Pb ages, Hf–O and whole-rock Sr–Nd isotopes, and whole-rock geochemistry of Cretaceous granitoids on Hainan Island and discuss their magmatic evolution within the framework of the Late Mesozoic geodynamics of SE China. We recognize two main stages of the emplacement of Cretaceous granitoids on Hainan, first around 120 Ma and then around 100–95 Ma, displaying high-K calc-alkaline, I-type geochemical affinities. Granites in both age groups are enriched in LILE and LREE, but depleted in Nb, Ta, Ba, Sr, and Eu. The 120 Ma granites have zircon εHf(t) values of –2.6 to 2.3 corresponding to Hf crustal model ages, ranging from 0.79 Ga to 1.03 Ga, and δ18O values ranging from 6.9‰ to 7.7‰. Zircons from 100–95 Ma granites have εHf(t) values of –4.2 to 1.1 corresponding to Hf crustal model ages of 1.08 Ga to 1.42 Ga, and δ18O values ranging from 6.7‰ to 8.4‰. Increasing εHf(t) values of the Cretaceous Hainan granites with younger crystallization ages indicate addition of more juvenile components and reworking of crustal material into their melt evolution. The εNd(t) values of the 120 Ma and 100–95 Ma granitoids range between –4.1 to –0.4 and –7.7 to –4.0, respectively. The calculated two–stage model age of the 100–95 Ma granitoids clusters between 1.25 Ga and 1.53 Ga. These isotopic data suggest that magmas of the Cretaceous granitoids were produced by partial melting of Mesoproterozoic metabasaltic rocks, which make up much of the crystalline basement of the southern Cathaysia block. The geochemical and isotopic characteristics of the Cretaceous granitoids on Hainan resemble those of magmatic arcs in the Circum–Pacific orogenic belts and identical to those of nearly coeval granitoid intrusions in the continental fragments within the South China Sea basin. We interpret these Cretaceous granitoids in the Peri–South China Sea region as the remnants of a once contiguous Late Mesozoic magmatic arc system that bounded the southern margin of the entire continental Southeast Asia. Our findings do not support the existence of an episode of magmatic quiescence in the geological record of SE China during the Aptian.
The development of laser ablation inductively coupled plasma quadrupole tandem mass spectrometry (LA-ICP-Q-MS/MS) opens new opportunities to rapidly date a variety of hydrothermal minerals. Here we present in situ Lu-Hf and Re-Os dates for hydrothermal apatite and molybdenite, respectively. We further report the first in situ Lu-Hf dates for bastnäsite, dolomite, and siderite, and assess their potential for constraining ore deposit geochronology. For method validation, we report isotope-dilution Lu-Hf dates for apatite reference material Bamble-1 (1102 ± 5 Ma) and calcite reference material ME-1 (1531 ± 7 Ma), enabling improved accuracy on matrix-matched calibration for LA-ICP-MS/MS Lu-Hf dating. The new methods are applied to the Vulcan Iron-Oxide Copper-Gold (IOCG) prospect in the Olympic Cu-Au Province of South Australia. Such deposits have been difficult to accurately date, given the general lack of reliable mineral geochronometers that are cogenetic with IOCG mineralisation. Hydrothermal apatite Lu-Hf dates and molybdenite Re-Os dates demonstrate that mineralisation at Vulcan largely occurred at ca. 1.6 Ga, contemporaneous with the world class Olympic Dam deposit. Our data also indicates that the Lu-Hf system in apatite is more robust than the U-Pb system for determining the timing of primary apatite formation in an IOCG system. We further demonstrate that dolomite can retain Lu-Hf growth ages over an extended time period (>1.5 billion years), providing constraints on the timing of primary ore mineral crystallisation during brecciation and IOCG mineralisation. Finally, late Neoproterozoic (ca. 589–544 Ma) and Carboniferous (ca. 334 ± 7 Ma) Lu-Hf dates were obtained for texturally late Cu-bearing carbonate veins, illustrating that the carbonate Lu-Hf method allows direct dating of Cu remobilisation events. This has important implications for mineral exploration as the remobilised Cu may have been transferred to younger deposits hosted in Neoproterozoic sedimentary basins overlaying the Olympic IOCG province.
The energy transition challenges faced by modern civilization have significantly enhanced the demand for critical metals like lithium resulting in improved methods to explore, extract, and utilize these metals. In this comprehensive review, we discuss the different types of lithium resources, factors, and mechanisms controlling lithium enrichment in various geological settings including terrestrial and marine environments. Diverse exploration strategies including geological, geophysical, mineralogical, geochemical, and remote sensing techniques including drone-based techniques for lithium exploration studies in different terranes are summarized. An overview of the mining techniques, including beneficiation and extraction, and their principles, mechanisms, operations, and comparison of the various approaches and compatibility with different types of lithium deposits for obtaining maximum yield are evaluated. Lithium isotopic studies are useful in understanding geological processes such as past weathering events and riverine input into the oceans, as well as in understanding the source of lithium in diverse types of deposits. We also highlight the recent developments in other areas such as recycling, environmental impact, and state-of-the-art analytical techniques for determining lithium in different lithium ore deposits and other geological materials. Our overview provides the latest developments and insights in the various sectors related to lithium and prompt further developments to meet the growing demand for this valuable metal as the world transforms to clean energy.
This study proposes an approach that considers mitigation strategies in predicting landslide susceptibility through machine learning (ML) and geographic information system (GIS) techniques. ML models, such as random forest (RF), logistic regression (LR), and support vector classification (SVC) are incorporated into GIS to predict landslide susceptibilities in Hong Kong. To consider the effect of mitigation strategies on landslide susceptibility, non-landslide samples were produced in the upgraded area and added to randomly created samples to serve as ML models in training datasets. Two scenarios were created to compare and demonstrate the efficiency of the proposed approach; Scenario I does not considering landslide control while Scenario II considers mitigation strategies for landslide control. The largest landslide susceptibilities are 0.967 (from RF), followed by 0.936 (from LR) and 0.902 (from SVC) in Scenario II; in Scenario I, they are 0.986 (from RF), 0.955 (from LR) and 0.947 (from SVC). This proves that the ML models considering mitigation strategies can decrease the current landslide susceptibilities. The comparison between the different ML models shows that RF performed better than LR and SVC, and provides the best prediction of the spatial distribution of landslide susceptibilities.
Phosphorus is one of the key elements, which determined the emergence of primordial life on our planet. The source of prebiotic phosphorus was most likely to be easily soluble compounds containing phosphorus in the negative form of oxidation (e.g., phosphides). The present paper is the first thorough investigation of phosphide-bearing mineral assemblages confined to telluric (terrestrial) native iron from volcanic rocks of Disko Island, Greenland. Phosphorus speciation in given assemblages varies from the solid solution in native iron (up to 0.3 wt.% P), different phosphides – schreibersite Fe3P, nickelphosphide Ni3P, barringerite Fe2P, and phosphates, including fluorapatite, anhydrous Fe-Na phosphates, phosphoran olivine and pyroxene (up to 1 wt.% P). The diversity of observed phosphorus speciation can be explained by the steep changes of redox conditions during subsurface crystallization of iron-phosphide-bearing lavas. Based on the available data on likely redox conditions on the early Earth, we hypothesize that reactive prebiotic phosphorus may have originated from shallow crustal rocks.
40Ar-39Ar geochronology, geochemistry, and Sr-Nd isotopic compositions of 30 core samples from 24 offshore drill wells in the Western offshore basins have been used to characterize the genetics of the volcanic basement from the Kutch, Mumbai, and Kerala-Konkan offshore basins. Findings from the volcanic basement rocks demonstrate extremely varied isotopic and geochemical fingerprints, which are suggestive of significantly diverse parent magma compositions and emplacement processes.
The accurate identification of dinosaur egg accumulations as nests or clutches is crucial for understanding the reproductive behaviour of these extinct species. However, existing methods often rely on the presence of complete eggs and embryo remains, and sedimentological criteria that are only applicable to well-structured sediments. In this study, we introduce an innovative approach to characterize egg accumulations in structureless sediments, where traditional nest structures may not be preserved. Our methodology employs a unique combination of sedimentological, taphonomic, geochemical, and geophysical proxies for the study of egg accumulations. We applied this approach to the egg accumulation from Paimogo (Jurassic, Portugal), traditionally interpreted as a nest. Our findings reveal that the Paimogo egg assemblage is a secondary deposit, resulting from a flooding event in a fluvial plain that dismantled several allosauroid and crocodylomorph clutches. The eggshell vapor conductance results, coupled with sedimentological evidence, suggest that allosauroid dinosaurs buried their eggs in the dry terrain of overbank areas close to a main channel during the breeding season, likely during the dry season to prevent the embryos from drowning. This research underscores the necessity of multidisciplinary approaches in interpreting egg accumulations and offers a novel methodology for studying these accumulations in structureless sediments. Our findings provide new insights into the breeding behaviour and nesting preferences of these extinct organisms, contributing to our understanding of dinosaur ecology.
The energy access challenge remains a significant barrier to sustainable development, with millions of people still needing access to modern energy services. Fossil fuels have played a crucial role in meeting electricity demand, but they face challenges and drawbacks in terms of environmental sustainability, energy security, and climate change. This study examines how renewable and non-renewable energy generation capacity impacted the environment in 53 upper-middle-income countries from 1990 to 2020, using energy access and alternative energy sources as mediating variables. The findings of this study provide valuable insights into the complex relationship between renewable energy generation capacity, energy access, alternative energy sources, and environmental conditions in upper-middle-income countries. The positive relationship between renewable energy generation capacity and environmental conditions emphasizes the importance and potential of renewable energy sources in mitigating environmental degradation. Additionally, the findings indicate that energy access also plays a crucial role in shaping energy generation patterns, with higher levels of access being associated with increased renewable energy generation and decreased reliance on non-renewable energy sources. These findings highlight the urgent need for policies and measures to promote renewable energy adoption and prioritize energy access to mitigate environmental degradation and achieve sustainable development goals.
Natural resource management is indispensable keeping in view their positive economic impacts as well as their detrimental environmental consequences. To achieve certain SDGs, it is inevitable to manage natural resources through effective policies that help to inhibit adverse environmental impacts. Based on this approach, the current empirical analysis aims to probe whether environmental policy stringency intensifies, meagres, and/or halts the abysmal environmental impact of natural resources in G-7 countries (United Kingdom, United States, Canada, Italy, France, Japan, and Germany) for the period from 1990 to 2020. To that end, we rely on the second-generation panel data approaches and panel quantile regression. The outcomes reveal that natural resources increase carbon dioxide emission whereas the synergy of natural resources and environmental policy stringency plunges emissions across the quantiles. These findings suggest adoption of a strict environmental policy for attaining the targets of SGD-08 (economic growth), SDG-09 (innovations), SDG-11 (sustainable cities), SDG-12 (responsible consumption of natural resources), and SDG-13 (climate action).
The Vuoriyarvi massif is a Devonian multistage alkaline-ultrabasic carbonatite complex within the Kola alkaline province. Dolomite carbonatites of the Vuoriyarvi massif contain abundant rare-earth mineralization mainly represented by ancylite-(Ce) and bastnäsite-(Ce). Ancylite was previously shown to have probably formed in the Devonian (ca. 365 Ma) during an early postmagmatic overprint. Previous geological observations have revealed a much later crystallization of bastnäsite but have not been able to specify the exact age of the mineralization. The in situ U-Pb dating of bastnäsite allowed us to constrain its genesis. Bastnäsite for this study was extracted from two varieties of dolomite carbonatite breccias cemented by (1) quartz-bastnäsite and (2) strontianite aggregates (hereafter bastnäsite-rich and strontianite-rich carbonatites – BRC and SRC, respectively). The obtained age estimations (237.7 ± 9.8 Ma and 239.9 ± 4.1 Ma, respectively) indicate that both studied rocks were formed during a single event. The revealed age difference (∼125 Ma) excludes the genetic link between the bastnäsite origin and regional alkaline magmatism, pointing out an additional source for the Vuoriyarvi bastnäsite-bearing rocks. Moreover, the obtained U-Pb ages provide strong evidence that a Triassic event is responsible for the occurrence of bastnäsite mineralization due to hydrothermal REE redistribution from the Devonian ancylite-rich carbonatites. Most of the REEs released during this process via dissolution of ancylite were precipitated in situ as bastnäsite, while strontium was transported and incorporated into strontianite. The Pb isotopic characteristics of bastnäsite (206Pb/204Pb = 18.1 ± 0.1, 207Pb/204Pb = 15.3 ± 0.1, and 207Pb/206Pb = 0.84 ± 0.01) are most probably inherited from the Devonian host rocks of the Vuoriyarvi massif involved in the Triassic overprint. Isotopic signatures of Pb, Sr, and Nd show that the depleted mantle and lower crust played the leading role in formation of the Vuoriyarvi alkaline complex. Taken together, the results of the present study negate the supergene origin of the Vuoriyarvi bastnäsite, implying that the bastnäsite mineralization is not confined to near-surface layers and, therefore, may be dispersed more broadly throughout the complex. These findings raise the question on underestimation of the probable REE reserves and lay the groundwork for a reassessment of the economic potential of the Vuoriyarvi complex.
The impact of hydro energy production, economic complexity, urbanization, technological innovation and financial development on environmental sustainability between 1995 and 2017 is examined for a panel of thirteen Asian economies using two environmental proxies— their ecological footprint and CO2 emissions. The non-parametric Driscoll-Kraay standard error method and the Dumitrescu-Hurlin panel causality test are applied to the data. Our findings show that hydro energy production and technological innovation have a significant negative impact on the environment, thus promoting environmental sustainability. Economic complexity significantly lowers environmental sustainability while the non-linear effect of economic complexity favors environmental sustainability; this confirms the existence of an economic-complexity-based inverted-U-shaped environmental Kuznets curve hypothesis. Moreover, urbanization and financial development significantly decrease environmental sustainability. The results of our study confirm the feedback causality between hydro energy production and carbon dioxide emissions. We recommend expansionary policies regarding hydro energy production that are beneficial for substituting fossil fuel energy. This paves a path towards environmental sustainability in this era of global boiling.
The unique ore-forming processes and the key factors responsible for formation of skarn deposits are still obscure, and challenges exist in the determination of timing of Pb-Zn skarns owing to lacking suitable mineral chronometers. Here we present detailed paragenesis, bulk geochemistry, in situ U-Pb dating of zircon and garnet, and garnet oxygen isotopes together with in situ zircon Hf-O isotopes from the newly discovered Aqishan Pb-Zn deposit in the southern Central Asian Orogenic Belt (CAOB), northwest China. This comprehensive data set revealed a Late Carboniferous subduction-related distal Pb-Zn skarn system associated with the granitic magmatism. Pre-ore stage garnets are generally subhedral to euhedral with oscillatory zoning and show slightly fractionated rare earth element patterns with positive Eu anomalies that point to an infiltration metasomatism origin under high water/rock ratios. The syn-ore stage sphalerite is typically enriched in Mn and Cd and has moderate Zn/Cd ratios (337–482), with a formation temperature of 265 °C to 383 °C, which indicate magmatic-hydrothermal signatures. The isocons defined by P2O5 decipher that the principal factors for skarn formation were elevated activities of Fe, Ca, and Si species, where remobilization of Pb metals, meanwhile, contributed to ore-forming budgets to mineralizing fluids. SIMS U-Pb dating of zircons from granite porphyry that occurs distal to the skarns and Pb-Zn orebodies shows that these intrusions emplaced at ca. 311.3–310.6 Ma, recording the subduction of the Paleo-Tianshan oceanic plate. Hydrothermal garnets in close textural association with Pb-Zn sulfides yield indistinguishable in situ LA-ICP-MS U-Pb ages of 310.5 ± 4.1 Ma. Whole-rock geochemistry and in situ zircon Hf-O isotopes (δ18O = 4.6‰–6.0‰) indicate that the granite porphyry was derived from partial melting of juvenile crust and influenced by subducted oceanic crust. Oxygen isotope compositions of garnets (δ18O = 8.0‰–9.0‰) demonstrate that the equilibrated ore fluids were inherited from fluid-rock interactions between a primary magmatic water and host tuff rocks. Our study highlights the application of garnets as a potential robust U-Pb geochronometer and isotopic tracer of ore fluids in skarn mineralizing systems in subduction-related arc environments.
