Geoscience frontiers最新文献

{"title":"Palynofloral and geochemical evidence for Permian-Triassic transition from Talcher Coalfield, Son-Mahanadi Basin, India: Insights into age, palaeovegetation, palaeoclimate and palaeowildfire","authors":"Srikanta Murthy ,&nbsp;Deveshwar P. Mishra ,&nbsp;Dieter Uhl ,&nbsp;Anju Saxena ,&nbsp;Vikram P. Singh ,&nbsp;Runcie P. Mathews ,&nbsp;Anurag Kumar ,&nbsp;Bindhyachal Pandey","doi":"10.1016/j.gsf.2025.102086","DOIUrl":"10.1016/j.gsf.2025.102086","url":null,"abstract":"<div><div>The Permian-Triassic (P/T) transition is marked by the most severe mass-extinction event of the Phanerozoic. Although much is known about this event in the marine realm, there are many open questions regarding what happened during this period to many continental biota. In the case of plants, a drastic mass-extinction event has even been negated by some authors. To add about the knowledge on continental biota in India during this crucial time period, the present study analysed the palynology, palynofacies, organic geochemistry (biomarkers), stable isotopes, and charcoal within the subsurface Gondwana deposits of the Kamthi Formation (late Permian-early Triassic) from core TTB-7 from the Tribida block, located in the Talcher Coalfield of the Mahanadi Basin, India.</div><div>The primary objectives are to validate the age of the strata, ascertain the palaeodepositional setting of the palaeomire, and propose palaeobotanical evidence regarding the occurrence of wildfires within this stratigraphic succession and changes in floral content across the P/T transition. The palynological study proposes two palynoassemblage zones, <em>Densipollenites magnicorpus</em> and <em>Klausipollenites schaubergeri,</em> suggesting a latest Permian (Lopingian) and early Triassic (Induan?) age for the studied succession, respectively. The age is also inferred based on correlation with coeval assemblages from India and other Gondwana continents. The palynoassemblages reveal the dominance of Glossopteridales and Coniferales along with Filicales, Lycopsidales, Equisetales, Cordaitales and Peltaspermales. The relatively higher values of the carbon preference index and terrigenous/aquatic ratio also suggest higher plant input. However, a bimodal <em>n</em>-alkane distribution pattern suggests the contribution of terrigenous and microbial sources. Although the occurrences of long-chain alkanes indicate input of higher plants, the low <em>P</em>_wax values (&lt;0.26) suggest relatively less contribution. The <em>P</em>_aqvalues (≅1) and amorphous organic matter (av. 33.24%) suggest a significant macrophyte input in the studied samples, pointing to the occurrence of moderate aquatic conditions in the basin.</div><div>Furthermore, the distribution of hopanoids and the content of degraded organic matter (av. 29.96%) reflect the bacterial degradation of organic matter. Also, the <em>δ</em>¹³C values of the studied section varied from −31.2‰ to −21.8‰. A large carbon isotopic offset of 9.4‰ across the P/T transition, Pr/Ph ratio (0.3–1.3) and shift in the distribution pattern of palynofacies components is indicating a significant change in climatic conditions. Moreover, the presence of macroscopic charcoal fragments of gymnospermous affinity with pre-charring colonization by fungi provides evidence for wildfire occurring during the Lopingian (Late Permian) in this basin.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102086"},"PeriodicalIF":8.5,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Orbital to millennial scale dust activity and humidity interaction in Central Asia during the last glacial period","authors":"Haoru Wei ,&nbsp;Yougui Song ,&nbsp;Shugang Kang ,&nbsp;Mingyu Zhang ,&nbsp;Mengping Xie ,&nbsp;Yanping Wang ,&nbsp;Li Han ,&nbsp;Shukhrat Shukurov ,&nbsp;Nosir Shukurov ,&nbsp;Fakhriddin Fayziev","doi":"10.1016/j.gsf.2025.102099","DOIUrl":"10.1016/j.gsf.2025.102099","url":null,"abstract":"<div><div>The factors controlling dust activity and humidity in Central Asia and their relationships remain controversial, partly due to a lack of high-resolution geological records for the mid-to-late last glaciation. In this study, we established an optically stimulated luminescence chronology for the QSHA profile in the Yili Basin, a region influenced by westerlies. Grain size and trace element data were used as paleoclimatic indicators. We investigated the relationships among Central Asian dust activity, humidity, and westerlies strength on orbital to millennial scale from 37.4 ka to 11.6 ka. Our study reveals that, on orbital timescales, humidity is positively correlated with westerlies strength which controlled by precession. Dust activity is controlled by Siberian High which was regulated by Northern Hemisphere high-latitude temperature. Their responses to low-latitude and high-latitude forcing mechanisms respectively and present an opposite relationship. On millennial timescales, humidity and westerlies strength are positively correlated. During Marine Isotope Stage (MIS) 2, humidity and dust activity show synchronous fluctuations, while during MIS 3, they exhibit an inverse relationship. Westerlies strength regulated humidity, which subsequently controlled glacial activity in the Tianshan Mountains, influencing dust activity in Central Asia. Additionally, the QSHA profile recorded seven Dansgaard-Oeschger (D-O) events on millennial timescales, indicating a potential link between Central Asian dust activity and high-latitude temperature variations in the Northern Hemisphere. Our findings provide new insights into dust and humidity interaction during the last glaciation periods in Central Asia and contribute to understanding global dust and hydrological cycles.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102099"},"PeriodicalIF":8.5,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting groundwater fluoride levels for drinking suitability using machine learning approaches with traditional and fuzzy logic models-based health risk assessment","authors":"D. Karunanidhi ,&nbsp;M.Rhishi Hari Raj ,&nbsp;V.N. Prapanchan ,&nbsp;T. Subramani","doi":"10.1016/j.gsf.2025.102087","DOIUrl":"10.1016/j.gsf.2025.102087","url":null,"abstract":"<div><div>The primary objective of this study is to measure fluoride levels in groundwater samples using machine learning approaches alongside traditional and fuzzy logic models based health risk assessment in the hard rock Arjunanadi River basin, South India. Fluoride levels in the study area vary between 0.1 and 3.10 mg/L, with 32 samples exceeding the World Health Organization (WHO) standard of 1.5 mg/L. Hydrogeochemical analyses (Durov and Gibbs) clearly show that the overall water chemistry is primarily influenced by simple dissolution, mixing, and rock-water interactions, indicating that geogenic sources are the predominant contributors to fluoride in the study area. Around 446.5 km² is considered at risk. In predictive analysis, five Machine Learning (ML) models were used, with the AdaBoost model performing better than the other models, achieving 96% accuracy and 4% error rate. The Traditional Health Risk Assessment (THRA) results indicate that 65% of samples pose highly susceptible for dental fluorosis, while 12% of samples pose highly susceptible for skeletal fluorosis in young age groups. The Fuzzy Inference System (FIS) model effectively manages ambiguity and linguistic factors, which are crucial when addressing health risks linked to groundwater fluoride contamination. In this model, input variables include fluoride concentration, individual age, and ingestion rate, while output variables consist of dental caries risk, dental fluorosis, and skeletal fluorosis. The overall results indicate that increased ingestion rates and prolonged exposure to contaminated water make adults and the elderly people vulnerable to dental and skeletal fluorosis, along with very young and young age groups. This study is an essential resource for local authorities, healthcare officials, and communities, aiding in the mitigation of health risks associated with groundwater contamination and enhancing quality of life through improved water management and health risk assessment, aligning with Sustainable Development Goals (SDGs) 3 and 6, thereby contributing to a cleaner and healthier society.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 4","pages":"Article 102087"},"PeriodicalIF":8.5,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The mechanism of carbon recycling into orogenic lithosphere: A Li isotope perspective","authors":"Xianlei Geng,&nbsp;Yang Yu,&nbsp;Shihong Tian,&nbsp;Wei Xu,&nbsp;Lu Chen,&nbsp;Zhengwei Liang,&nbsp;Wenjie Hu,&nbsp;Na Lu,&nbsp;Jiawen Liu","doi":"10.1016/j.gsf.2025.102111","DOIUrl":"10.1016/j.gsf.2025.102111","url":null,"abstract":"<div><div>Subducting slabs transport carbon to deep mantle depths and release it into the overlying mantle wedge and lithospheric mantle through multiple mechanisms, including mechanical removal via diapirism, metamorphic decarbonization, carbonate dissolution and parting melting. Identifying the dominant carbon recycling mechanism responsible for carbonation of subcontinental lithospheric mantle (SCLM) remains challenging, yet it is critical for understanding the genesis of post-collisional carbonatites and associated rare earth element deposits. To address this issue, we investigate the Li isotopic systematics of typical post-collisional carbonatite-alkalic complexes from Mianning-Dechang (MD), Southeast Tibet. Our results show that the less-evolved magmas (lamprophyres) have mantle-like or slightly lower <em>δ</em>⁷Li values (0.3‰–3.6‰) with limited variability, contrasting sharply with the wider <em>δ</em>⁷Li range observed in associated carbonatites and syenites. We interpret this dichotomy as reflecting distinct processes: while the variable and anomalous <em>δ</em>⁷Li values in differentiated rocks (carbonatites and syenites) were caused by late-stage magmatic-hydrothermal processes (including biotite fractionation, fluid exsolution and hydrothermal alteration), the lamprophyres retain the primary Li isotopic signature of their mantle source. Together with their arc-like trace element and EM1-EM2-type Sr-Nd-Pb isotopic signatures, such mantle-like or slightly lower <em>δ</em>⁷Li values of the lamprophyres preclude carbon derivation from high-<em>δ</em>⁷Li reservoirs (altered oceanic crust, serpentinites) and recycling of sedimentary carbon through metamorphic decarbonization or dissolution. Instead, these features indicate that the carbon was predominantly transported into the mantle source via partial melting of subducted carbonate-bearing sediments. This study demonstrates that Li isotopes can serve as a tracer for identifying the mechanism of carbon recycling in collision zones.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102111"},"PeriodicalIF":8.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of overburden layer thickness based on spatial heterogeneity analysis and machine learning models in hillslope regions","authors":"Zhilu Chang ,&nbsp;Shui-Hua Jiang ,&nbsp;Faming Huang ,&nbsp;Lei Shi ,&nbsp;Jinsong Huang ,&nbsp;Jianhong Wan ,&nbsp;Filippo Catani","doi":"10.1016/j.gsf.2025.102109","DOIUrl":"10.1016/j.gsf.2025.102109","url":null,"abstract":"<div><div>The spatial distribution of overburden layer thickness (OLT) is crucial for landslide susceptibility prediction and slope stability analysis. Due to OLT spatial heterogeneity in hillslope regions, combined with the difficulty and time consumption of OLT sample collection, accurately predicting OLT distribution remains a challenging. To address this, a novel framework has been developed. First, OLT samples are collected through field surveys, remote sensing, and geological drilling. Next, the heterogeneity of OLT’s spatial distribution is analyzed using the probability distribution of OLT samples and their horizontal and vertical distributions. The OLT samples are categorized and the small sample categories are expanded using the synthetic minority over-sampling technique (SMOTE). The slope position is selected as a key conditioning factor. Subsequently, 16 conditioning factors are applied to construct OLT prediction model using the random forest regression algorithm. Weights are assigned to each OLT sample category to balance the uneven distribution of sample sizes. Finally, the Pearson correlation coefficient, mean absolute error (MAE), root mean square error (RMSE), and Lin’s concordance correlation coefficient (Lin’s CCC) are employed to validate the OLT prediction results. The Huangtan town serves as the case study. Results show: (1) heterogeneity analysis, SMOTE-based OLT sample expansion strategy and slope position selection can significantly mitigate the effect of spatial heterogeneity on OLT prediction. (2) The Pearson correlation coefficient, RMSE, MAE and Lin’s CCC values are 0.84, 1.173, 1.378 and 0.804, respectively, indicating excellent prediction performance. This research provides an effective solution for predicting OLT distribution in hillslope regions.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102109"},"PeriodicalIF":8.5,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preservation potential of Cambrian small shelly fossils in different microfacies, North China","authors":"Yazhou Hu ,&nbsp;Timothy P. Topper ,&nbsp;Luke C. Strotz ,&nbsp;Yue Liang ,&nbsp;Fan Liu ,&nbsp;Rao Fu ,&nbsp;Baopeng Song ,&nbsp;Zhao Wang ,&nbsp;Bing Pan ,&nbsp;Zhifei Zhang","doi":"10.1016/j.gsf.2025.102108","DOIUrl":"10.1016/j.gsf.2025.102108","url":null,"abstract":"<div><div>Small shelly fossils (SSFs) have long been recognized as important to the studies of both metazoan evolution and the onset of biomineralization during the Cambrian radiation. The marked decline in the occurrence, diversity and abundance of SSFs in the middle to late Cambrian, when compared with the early Cambrian, has often been regarded as a result of the closure of a phosphatization window. Despite this, there have been numerous and consistent reports of SSFs from the middle Cambrian and younger deposits. To identify possible factors influencing SSF preservation, five microfacies including bioclastic limestone, flat-pebble conglomerates with bioclasts, hummocky cross-stratified grainstone with bioclasts, bioclastic grainstone in hardgrounds and glauconite bioclastic wackstone-packstone, from Cambrian Series 2 to Miaolingian in North China are compared to assess how differences in lithology impact the preservation potential of SSFs. Our results, based on 35,161 SSF specimens from deposits across six sections, suggest that there are still abundant and diverse SSFs in the middle Cambrian of North China preserved in ways not exclusively reliant on the presence of phosphate and that SSF preservation can be linked to the differences in microfacies in the early to middle Cambrian of North China.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102108"},"PeriodicalIF":8.5,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The net warming effect of clouds on global surface temperature may be weakening or even disappearing","authors":"Chuanye Shi ,&nbsp;Tianxing Wang ,&nbsp;Gaofeng Wang ,&nbsp;Husi Letu","doi":"10.1016/j.gsf.2025.102107","DOIUrl":"10.1016/j.gsf.2025.102107","url":null,"abstract":"<div><div>Climate change is significantly influenced by both clouds and Earth’s surface temperature (EST). While numerous studies have investigated clouds and EST separately, the extent of clouds’ impact on EST remains unclear. Based on the inspiration and limitation of cloud radiative effect (CRE), this study provides a pioneering attempt to propose a novel indicator, cloud radiative effect on surface temperature (CREST), aiming to quantify how clouds affect EST globally while also analyzing the physical mechanism. Using reanalysis and remotely sensed data, a phased machine learning scheme in combination of surface energy balance theory is proposed to estimate EST under all-sky and hypothetical clear-sky conditions in stages, thereby estimating the newly defined CREST by subtracting the hypothetical clear-sky EST from the all-sky EST. The inter-annual experiments reveal the significant spatial heterogeneity in CREST across land, ocean, and ice/snow regions. As a global offset of the heterogeneity, clouds exhibit a net warming effect on global surface temperature on an annual scale (e.g., 0.26 K in 1981), despite their ability to block sunlight. However, the net warming effect has gradually weakened to nearly zero over the past four decades (e.g., only 0.06 K in 2021), and it’s even possible to transform into a cooling effect, which might be good news for mitigating the global warming.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102107"},"PeriodicalIF":8.5,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effusive and explosive silicic eruptions during India-Seychelles continental breakup: the 62.5 Ma Dongri-Uttan rhyolite sequence, Mumbai area, western Deccan Traps","authors":"Arunodaya Shekhar ,&nbsp;Hetu Sheth ,&nbsp;Anmol Naik ,&nbsp;B. Astha","doi":"10.1016/j.gsf.2025.102106","DOIUrl":"10.1016/j.gsf.2025.102106","url":null,"abstract":"<div><div>Large-scale Danian-age (post-K/Pg boundary) Deccan magmatism is well known from the Mumbai metropolitan area, located in the structurally complex Panvel flexure zone along the western Indian rifted continental margin. This compositionally diverse late-Deccan magmatic suite contains subaerial tholeiitic lavas and dykes typical of the main Deccan province, with many features atypical of the Deccan, such as spilitic pillow lavas, “intertrappean” sediments (often containing considerable volcanic ash), rhyolitic lavas and tuffs, gabbro-granophyre intrusions, and trachyte intrusions containing alkali basalt enclaves. Most of these units, previously dated at 62.5 Ma to 61 Ma, are contemporaneous with or slightly postdate the 62.5 Ma India-Seychelles continental breakup and Panvel flexure formation. In the Dongri-Uttan area, two samples of a &gt;50-m-thick, columnar-jointed rhyolite from the Darkhan Quarry and from a section behind the current Uttan Sagari Police Station have previously been dated at 62.6 ± 0.6 Ma and 62.9 ± 0.2 Ma (⁴⁰Ar/³⁹Ar, 2σ errors). New exposures reveal that these two statistically indistinguishable ⁴⁰Ar/³⁹Ar ages correspond to two distinct rhyolite units, separated by well-bedded silicic ash. The columnar rhyolites are microcrystalline, composed of quartz and alkali feldspar, with rare small (1–2 mm), altered feldspar phenocrysts, and no recognisable relict vitroclasts. Given the westerly structural dip, most of their lateral extent is submerged under the Arabian Sea, and we consider them to be possible <em>flood rhyolite</em> lavas. We interpret the ash beds, composed of pumice clasts and glass shards, as a low-grade (nonwelded) vitric ash, derived from a possibly distal Plinian eruption and deposited by fallout. The lavas and ash are peraluminous rhyolites. The lavas are Sr-Ba-poor and Rb-Zr-Nb-rich, and show “seagull-shaped” rare earth element patterns with deep negative europium anomalies. These crystal-poor lavas are “hot-dry-reduced” rhyolites typical of intraplate, continental rift and rifted margin settings. The very different high-field strength element contents of the lavas and the ash indicate compositionally distinct magma batches. The 62.5 Ma Dongri-Uttan sequence provides clear evidence for rapid silicic eruptions of effusive and explosive nature, alternating with each other and sourced from distinct magma chambers and eruptive vents. A newly identified, highly feldspar-phyric trachyte intrusion marks the last phase of magmatic activity in the area, corresponding with late-stage trachyte-syenite intrusions exposed in coastal western India and the Seychelles, and shows that the Mumbai rhyolites and trachytes form a compositional continuum.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102106"},"PeriodicalIF":8.5,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Migration characteristics of geothermal fluids in karst geothermal reservoirs in the Beijing-Tianjin-Hebei Plain","authors":"Xiang Mao ,&nbsp;Jinxia Liu ,&nbsp;Lu Luo ,&nbsp;Shaochuan Sun ,&nbsp;Chenbingjie Wu ,&nbsp;Nanan Gao ,&nbsp;Huiying Liu ,&nbsp;Rui Liu","doi":"10.1016/j.gsf.2025.102104","DOIUrl":"10.1016/j.gsf.2025.102104","url":null,"abstract":"<div><div>The Beijing-Tianjin-Hebei Plain is among the regions in China that feature the largest scale and the fastest growth in medium and deep geothermal heating. Based on tests of 82 geothermal fluid samples from 7 geothermal fields in Hebei Province, 2 geothermal fields in Henan Province, and 2 geothermal fields in Shandong Province, and combined with previous studies on the chemical characteristics of karst geothermal water in Beijing and Tianjin, this paper systematically analyzes the migration characteristics of geothermal fluids in karst geothermal reservoirs within the Beijing-Tianjin-Hebei Plain. The hydrochemical characteristics of karst geothermal water in the research areas exhibit certain differences. The geothermal water in Hebei is more mature than that in its neighboring provinces. The distribution of total dissolved solids (TDS) and strontium elements in the area is characterized by being low in the north and south and high in the middle, suggesting that the overall flow direction of geothermal fluid is from the north and south towards the middle. Combined with the groundwater flow field and the changing trend of the hydrochemical characteristics of geothermal wells along the geological section, a geothermal water migration model has been established. The geothermal fluids originating from Taihang Mountain, Yanshan Mountain, and Western Shandong Mountain enter the basin and continue to migrate towards the central part of the basin along water-conducting faults. However, the migration characteristics of geothermal fluids with the same supply direction are not identical. The geothermal fluids from Taihang Mountain are cut off by the Niudong Fault in the north and terminate in the central uplift belt of the Jizhong Depression, while in the south, they enter the east of the Jizhong Depression relatively quickly along the Hengshui Conversion Belt. The geothermal fluids from Yanshan Mountain migrate into the basin along the Cangdong Fault, yet this fault also disrupts the hydraulic connection between the tectonic units. Considering the effective dynamic conditions, it is recommended to further expand the scale of the scientific development and utilization of geothermal energy in the geothermal water catchment areas around Xiongxian County and southwest Cangzhou City.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102104"},"PeriodicalIF":8.9,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144763712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the groundwater recharge processes in intensively irrigated regions: An approach combining isotope hydrology and machine learning","authors":"Md. Arzoo Ansari ,&nbsp;Jacob Noble ,&nbsp;U.Saravana Kumar ,&nbsp;Archana Deodhar ,&nbsp;Naima Akhtar ,&nbsp;Priyanka Singh ,&nbsp;Rishi Raj","doi":"10.1016/j.gsf.2025.102105","DOIUrl":"10.1016/j.gsf.2025.102105","url":null,"abstract":"<div><div>Agriculture is a major contributor to the global economy, accounting for approximately 70% of the freshwater use, which cause significant stress on aquifers in intensively irrigated regions. This stress often leads to the decline in both the quantity and quality of groundwater resources. This study is focused on an intensively irrigated region of Northern India to investigate the sources and mechanism of groundwater recharge using a novel integrated approach combining isotope hydrology, Artificial Neural Network (ANN), and hydrogeochemical models. The study identifies several key sources of groundwater recharge, including natural precipitation, river infiltration, Irrigation Return Flow (IRF), and recharge from canals. Some groundwater samples exhibit mixing from various sources. Groundwater recharge from IRF is found to be isotopically enriched due to evaporation and characterized by high Cl⁻. Stable isotope modeling of evaporative enrichment in irrigated water helped to differentiate the IRF during various cultivation periods (<em>Kharif</em> and <em>Rabi</em>) and deduce the climatic conditions prevailed during the time of recharge. The model quantified that 29% of the irrigated water is lost due to evaporation during the <em>Kharif</em> period and 20% during the <em>Rabi</em> period, reflecting the seasonal variations in IRF contribution to the groundwater. The ANN model, trained with isotope hydrogeochemical data, effectively captures the complex interrelationships between various recharge sources, providing a robust framework for understanding the groundwater dynamics in the study area. A conceptual model was developed to visualize the spatial and temporal distribution of recharge sources, highlighting how seasonal irrigation practices influence the groundwater. The integration of isotope hydrology with ANN methodologies proved to be effective in elucidating the multiple sources and processes of groundwater recharge, offering insights into the sustainability of aquifer systems in intensively irrigated regions. These findings are critical for developing data-driven groundwater management strategies that can adapt to future challenges, including climate change, shifting land use patterns, and evolving agricultural demands. The results have significant implications for policymakers and water resource managers seeking to ensure sustainable groundwater use in water-scarce regions.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102105"},"PeriodicalIF":8.5,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}