Geoscience frontiers最新文献

{"title":"Tracing carbonate diagenesis and hydrothermal activity during the opening of the Central South Atlantic: Insights from the Santos Basin (Brazil)","authors":"Igor Figueiredo ,&nbsp;Cristiano Lana ,&nbsp;Fernando F. Alkmim ,&nbsp;Marco A. Silva ,&nbsp;Maria Eugênia S. Souza ,&nbsp;Dorval C. Dias-Filho ,&nbsp;Eveline E. Zambonato ,&nbsp;Katia R.N. Mendonça","doi":"10.1016/j.gsf.2025.102115","DOIUrl":"10.1016/j.gsf.2025.102115","url":null,"abstract":"<div><div>The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism, carbonate sedimentation, and deposition of a thick salt layer. The carbonates underlying the salt layer (pre-salt carbonates) were formed in restricted lacustrine basins. Here, the timing and fluid sources of deposition, diagenetic, and hydrothermal alterations of the pre-salt carbonate rocks are defined through <em>in-situ</em> U-Pb dating, ⁸⁷Sr/⁸⁶Sr, and trace element analyses of samples from the Santos Basin. The very alkaline nature of the Aptian lake(s) produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution. Hydrothermalism caused extensive replacement, dissolution, and calcite cementation. REE+Y PAAS-normalised patterns and ⁸⁷Sr/⁸⁶Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation, pH, and continental water source, with 2%–10% hydrothermal fluid input. Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a<!--> <!-->hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations. U-Pb dating indicates that carbonate deposition occurred between 124.8 ± 2.6 Ma and 120.0 ± 1.6 Ma, earlier than previously proposed, followed closely by the circulation of hydrothermal fluids. Replacement and cementation ages range from 120.5 ± 2.4 Ma to 80.4 ± 2.4 Ma.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102115"},"PeriodicalIF":8.5,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704551","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 and early warning analysis of reservoir bank slopes based on anti-sliding stability evolution","authors":"Yaoru Liu ,&nbsp;Chenfeng Gao ,&nbsp;Wenyu Zhuang ,&nbsp;Chengyao Wei ,&nbsp;Zhenlian Qi ,&nbsp;Kai Zhang ,&nbsp;Shaokang Hou","doi":"10.1016/j.gsf.2025.102113","DOIUrl":"10.1016/j.gsf.2025.102113","url":null,"abstract":"<div><div>The stability of reservoir bank slopes during the impoundment period has become a critical issue in the construction and operation of large-scale hydropower projects. A predictive and early warning method for reservoir bank slopes is proposed, based on slip resistance stability evolution analysis. Using a refined three-dimensional numerical calculation model of the bank slope, the creep damage model is employed for simulation and analysis, enabling the derivation of stress field and strain field evolution from bank slope excavation to the long-term impoundment period. Subsequently, for the stress field of the bank slope at any given moment, the safety factors of the sliding blocks are determined by using the multigrid method and vector sum method. Accordingly, the evolutionary law of the sliding safety factor for the bank slope can be derived. By integrating the long-term stability evolution trend of the slope with specific engineering practices, the safety factors for graded warning can be determined. Based on the time correspondence, the graded warning moment and the deformation warning index for slope measurement points can be determined. In this study, the proposed method is applied to the left bank slope of the Jinping I Hydropower Station. The results indicate that from excavation to June 2022, the left bank slope exhibits a strong correlation with excavation elevation and the number of reservoir water cycles. The initial, maximum, and minimum safety factors are 2.01, 3.07, and 1.58, respectively. The deep fracture SL_44-1 serves as the primary stress-bearing slip surface of the left bank slope, while the safety margin of the fault f_42-9 and lamprophyre X is slightly insufficient. Based on the long-term stability evolution trend of the slope and in accordance with relevant standards, the safety factors for graded warning indicators—<em>K_w</em>₁, <em>K_w</em>₂, <em>K_w</em>₃, and <em>K_w</em>₄—are determined as 1.350, 1.325, 1.300, and 1.275, respectively. Correspondingly, the estimated warning times are 12/30/2066, 12/30/2084, and 12/30/2120. Accordingly, the deformation graded warning indexes for slope measurement points are established.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102113"},"PeriodicalIF":8.5,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656169","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":"Stepwise aridification of the Late Paleozoic North China Craton","authors":"Weikai Xu ,&nbsp;Yong Li ,&nbsp;Thomas J. Algeo ,&nbsp;Zhuangsen Wang ,&nbsp;Xiaofang He","doi":"10.1016/j.gsf.2025.102114","DOIUrl":"10.1016/j.gsf.2025.102114","url":null,"abstract":"<div><div>The Late Paleozoic marked Earth’s most recent icehouse–greenhouse transition, providing valuable insights into future climate and environmental changes. Although the aridification of the North China Craton (NCC) during the Late Paleozoic is well established, its pattern and causes remain unclear. Here, we identify four aridification intervals from the late Gzhelian to Lopingian by analyzing continuous records of elemental climate proxies (MgO/CaO, Sr/Cu), a volcanism proxy (Hg/TOC), and spore–pollen assemblages. Interval I (∼303–295 Ma), during which the NCC was located at low paleolatitudes, was characterized by humid conditions and a predominance of ferns, associated with weak volcanism. Interval II (∼295–286 Ma) was subhumid, with increasing gymnosperm presence, and significant climate fluctuations linked to volcanism. CO₂ emissions from the Tarim LIP and Panjal Traps drove aridification from the late Asselian to late Artinskian, contributing to the decline of the Late Paleozoic Ice Age. As a result, aridification in the NCC lagged behind that of Pangea. Interval III (∼286–280.98 Ma) marked the transition to subarid conditions and the onset of dominance by gymnosperms, associated with a rapid northward drift of the NCC and an increase in atmospheric <em>ρ</em>CO₂. Interval IV (∼259.51–251.902 Ma), separated from the underlying Interval III by a major regional unconformity (∼280.98–259.51), coincided with global aridification and intensified volcanism. These findings highlight the significant influences of both tectonic plate motion and volcanism on the climate evolution of the NCC, with shifts in the dominant controlling factors through time. This study provides new insights into the distinct trajectories of global and regional climate dynamics.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102114"},"PeriodicalIF":8.5,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656168","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":"Geological, structural, and temporal framework of hematite-rich IOCG mineralization at La Farola deposit in the Candelaria-Punta del Cobre district, Chile","authors":"N.M. Seymour ,&nbsp;I.del Real ,&nbsp;A. Canales ,&nbsp;H. Stein ,&nbsp;G. Yang ,&nbsp;J. Camacho","doi":"10.1016/j.gsf.2025.102112","DOIUrl":"10.1016/j.gsf.2025.102112","url":null,"abstract":"<div><div>Iron oxide-copper–gold (IOCG) deposits encompass a diverse set of mineralization styles, leading to outstanding questions about how different alteration facies are related across a single ore-producing system and the overarching mechanisms of ore genesis. This study investigates the age and characteristics of mineralization at the La Farola deposit, a hematite-dominated IOCG deposit located at the southern margin of the Candelaria-Punta del Cobre IOCG district of northern Chile. Two lithologically-controlled ore bodies occur along the WSW-ENE striking, ∼18° NNW-dipping contact between the Lower Cretaceous Chañarcillo Group and Punta del Cobre Formation. Syn-mineralization N-S to NNW-SSE striking sinistral strike-slip faults likely acted as fluid pathways. Distinct mineral assemblages include an early Na-Ca assemblage (albite-scapolite) overprinted by skarnoid garnet with minor pyroxene, Ca-Fe (magnetite-actinolite), and K-Fe (magnetite-k-feldspar-biotite and minor sulfides) assemblages. The main sulfide mineralization (chalcopyrite-pyrite with minor bornite) is associated with specular hematite-white mica-K-feldspar-calcite and overprints all previous assemblages. The presence of hematite as the dominant Fe-oxide phase associated with Cu mineralization is characteristic of lower-temperature IOCG deposits, and may be a result of La Farola’s stratigraphic position &lt;700 m higher than other deposits in the district. New U-Pb ages of 115.7 ± 1.2 Ma for garnet and Re-Os ages of ∼113–114 Ma for sulfides indicate mineralization occurred within a 3-million-year timeframe. These findings confirm hematite-dominant mineralization at La Farola was coeval with IOCG mineralization across the district. This research contributes to understanding IOCG systems and their formation mechanisms, highlighting the control local geological structures and alteration processes has on the diversity of mineralization types associated with a single IOCG system.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 5","pages":"Article 102112"},"PeriodicalIF":8.5,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694498","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":"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}