Geological Journal最新文献

{"title":"The Ebaka Para Derivative Migmatite (Central African Fold Belt): Typology, Petrology, U–Th–Pb Age and Hinterland Evolution","authors":"Alembert Alexandre Ganwa,&nbsp;Naimou Seguem,&nbsp;Urs Klötzli","doi":"10.1002/gj.70118","DOIUrl":"https://doi.org/10.1002/gj.70118","url":null,"abstract":"<div>\u0000 \u0000 <p>The Yaoundé Group is one of numerous Pan-African basins located north of the Congo Craton in central Africa. One of the main characteristics of this basin is the presence of high-grade gneisses and granulites which have been considered the root of the collision between the Central Africa Fold Belt and the Congo Craton. Interpretation of these high-grade rocks is mainly based on studies (petrology metamorphism, geochronology) carried out in the southern part of the WSW–ENE trending Yaoundé basin. The northeastern part of the basin (Belabo area) was filled by detritus of magmatic rocks (Sm/Nd = 0.182) of Rhyacian (2263 Ma) to Statherian (1677–1757 Ma) eras, of the southern Adamawa domain, and which have been later transformed by in situ partial melting into metatexitic to diatexitic migmatites (with a melt fraction less than 85%). Whole-rock chemical analyses show that the melanosome portion (sample EB1) is enriched in refractory elements with respect to the leucosome (sample EB3). This high-grade paroxysmal episode of metamorphism is characterised by a Sil–Kfsp–Pl–Bt–Grt assemblage and took place between 724 and 620 Ma (²⁰⁶Pb/²³⁸U zircon apparent ages). Few metamorphic transformations took place, especially Bt + Sil + Qtz = Grt + Kfsp + melt and Bt + Grt = Pl + Opq + melt. The evolution of the Yaoundé sedimentary basin was diachronic, starting earlier in the northeastern part (Ebaka region) with respect to the southwestern part (Yaoundé region).</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2875-2898"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paleoenvironmental and Paleodepositional Reconstruction of the Permian Coals From Burhar Seam IV of Sohagpur Coalfield, India: Using Integrated Mineralogical, Geochemical and Petrographic Proxies","authors":"Kaushal Kishor,&nbsp;Manish Kumar Srivastava,&nbsp;Gyan Prakash Tripathi,&nbsp;Alok K. Singh,&nbsp;Soumyajit Mukherjee","doi":"10.1002/gj.70113","DOIUrl":"https://doi.org/10.1002/gj.70113","url":null,"abstract":"<div>\u0000 \u0000 <p>Deciphering the paleoenvironment from coal samples is of great academic and industrial relevance. Coal samples from the Burhar seam IV, Sharda coalmine of the Sohagpur coalfield, were analysed using a multi-proxy approach to interpret paleoclimate and paleo-depositional conditions. The analysis incorporated several techniques, viz., Ultimate Analysis, X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) Spectroscopy and coal petrography. The Sohagpur coal deposit is a part of the Lower Gondwana coal group, which is characterised by high ash content resulting from proximate analysis. While XRD and FT-IR spectra identify the mineral components in the coal, XRF results show different oxide and elemental concentrations. Micropetrography provided insights into the maceral and mineral constituents of the samples. XRD, XRF and FT-IR results indicate a warm and humid paleoclimate favoured by intense chemical weathering, evidenced by the presence of minerals such as kaolinite. Depositional conditions were further examined through sulphur content analysis using Ultimate Analysis and elemental concentrations from the XRF. These suggest deposition in a transitional environment between oxic and suboxic conditions. Petrographic analysis also supported these findings, which indicate the coal samples were deposited in alternating oxic and anoxic moor conditions, with good tissue preservation.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2770-2786"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical and Geological Investigation of Skarn-Type Pb–Zn Mineralization in Hastanetepe (Balya-Balıkesir, Türkiye): An Approach Based on Fluid Inclusions, Sulphur Isotopes and Geochemical Data","authors":"Esra Ünal-Çakır","doi":"10.1002/gj.70280","DOIUrl":"https://doi.org/10.1002/gj.70280","url":null,"abstract":"<p>The Hastanetepe Pb–Zn deposit is located in the Biga Peninsula (northwestern Anatolia), one of the most important Pb–Zn metallogenic provinces in Türkiye. Mineralization occurs at the contact between Permian carbonate units and Cenozoic dacitic volcanic rocks. This study aims to constrain the genesis and hydrothermal evolution of the Hastanetepe deposit and to assess its metallogenic affinity within regional skarn-type systems of the Biga Peninsula. Petrographic observations are integrated with major and trace element geochemistry, fluid inclusion microthermometry and sulphur isotope (δ³⁴S) analyses. The ore assemblage consists of pyrite, sphalerite, galena, chalcopyrite and tetrahedrite–tennantite, hosted by a gangue assemblage dominated by quartz, calcite, epidote and garnet, indicating carbonate-related metasomatic alteration. Fluid inclusion analyses reveal homogenization temperatures ranging from 197°C to 450°C, with sphalerite recording significantly higher temperatures (average 435°C) than quartz (average 269°C), together with salinities ranging from 2.6 to 31.6 wt% NaCl equivalent, reflecting a multi-stage fluid evolution characterised by cooling, phase separation and late-stage fluid modification. Sulphur isotope values (δ³⁴S = −0.7 to +2.4‰) of sphalerite and galena cluster around 0‰, indicating a homogeneous magmatic sulphur source. The combined interpretation of fluid inclusion and sulphur isotope data indicates that the Hastanetepe deposit represents a carbonate-hosted Zn–Pb skarn system formed by high-temperature magmatic–hydrothermal fluids, followed by later hydrothermal overprinting. These characteristics are consistent with skarn-type mineralization associated with Oligo–Miocene magmatism in the Biga Peninsula and support classifying Hastanetepe as part of a regional Pb–Zn skarn metallogenic framework.</p>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2940-2957"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/gj.70280","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148910025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Do Fossil Fuel Consumption, Eco-Friendly Technology and Financial Development Have an Impact on Environmental Quality Under the LCC Hypothesis? Evidence From E-7 Countries","authors":"Serhat Çamkaya,&nbsp;Yunus Kaya,&nbsp;Said Khalfa Brika,&nbsp;Abdulkadir Barut,&nbsp;Kishwar Ali","doi":"10.1002/gj.70108","DOIUrl":"https://doi.org/10.1002/gj.70108","url":null,"abstract":"<div>\u0000 \u0000 <p>This study aims to test the long-run and short-run impact of fossil fuel consumption (FC), environmentally friendly technology (EFT) and financial development (FD) in E7 countries within the framework of the Load Capacity Curve (LCC) hypothesis. In line with this objective, this effect is tested using the CS-ARDL procedure for the period 1985–2019. Moreover, the Emirmahmutoğlu and Köse panel causality test is utilised to test the causal link between the variables. CS-ARDL findings show that the LCC hypothesis is not valid and that FC deteriorates environmental quality in E7 countries. Moreover, the findings reveal that FD and EFT improve environmental quality by increasing the load capacity factor (LCF). Causality findings show that there is a bidirectional causal link between LCF and the related independent variables. Based on the empirical findings, a series of policy recommendations are presented. Accordingly, E7 countries should increase the use of renewable energy, transition to a green and circular economy and promote EFT to realise sustainable development (SD).</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2661-2681"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two Types of Neoproterozoic Granitoids Reveal the Multi-Stage Tectonic Evolution of the South Altyn Tagh, Spanning From Rodinia's Disintegration to Palaeozoic Continental Deep Subduction","authors":"Yongsheng Gai,&nbsp;Liang Liu,&nbsp;Xiaoying Liao,&nbsp;Tuo Ma,&nbsp;Lei Kang,&nbsp;Chao Wang,&nbsp;Wenqiang Yang","doi":"10.1002/gj.70116","DOIUrl":"https://doi.org/10.1002/gj.70116","url":null,"abstract":"<div>\u0000 \u0000 <p>The South Altyn Tagh (SAT) is renowned for hosting high-pressure to ultrahigh-pressure (HP–UHP) rocks indicative of continental deep subduction. Nevertheless, its geodynamic evolution remains enigmatic due to uncertainty regarding protolith origins and the intricate relationships between HP–UHP rocks and their coeval, unmetamorphosed or low-grade metamorphic counterparts. This study presents novel LA–ICP–MS zircon U–Pb ages, zircon Lu–Hf isotopic compositions and whole-rock geochemical analyses of both HP–UHP felsic gneiss and unmetamorphosed to low-grade metamorphic Neoproterozoic granite samples from the SAT, northwestern China. Our findings indicate that both felsic gneiss and granite samples share protolith ages ranging from 920 to 898 Ma, displaying a high K₂O content and low CaO and Na₂O contents, characteristic of S-type granites. The presence of inherited zircons with ages of 1.79–1.40 Ga, along with <i>ε</i>\u0000 _Hf (<i>t</i>) values of –5.32 to +4.03 and <i>T</i>\u0000 _DM2 ages of 2.00–1.54 Ga for ~900 Ma zircons, suggests that both felsic gneisses and granite samples originated from the partial melting of Mesoproterozoic metasedimentary rocks. Zircon grains of felsic gneiss samples exhibit a metamorphic age cluster at 505–498 Ma, consistent with the ~500 Ma continental deep subduction event in the SAT. Conversely, granite samples lack ~500 Ma metamorphic age records; a few granite samples record a younger anatectic age cluster at 455–452 Ma, indicating the influence of a ~450 Ma post-collisional extension event in the SAT. Integrating petrological and geochemical investigations of both felsic gneisses and Neoproterozoic granite samples in the SAT and adjacent orogens, we propose that: (1) both the felsic gneisses and Neoproterozoic granites in the region formed during the late syn-collision to extensional collapse of the Rodinia supercontinent, (2) the rifting of Rodinia (860–623 Ma) resulted in the development of the Proto-Tethys ocean and the isolation of granite plutons along margins of different continental blocks, (3) the early-Palaeozoic continental collision (~500 Ma) subjected the Neoproterozoic granite in the subduction plate to continental deep subduction and led to the coexistence of HP–UHP felsic gneiss and non-subducted Neoproterozoic granite in the SAT after the exhumation process. These results demonstrate that HP–UHP felsic gneisses and Neoproterozoic granites preserve a complex tectono-metamorphic history spanning Rodinia's fragmentation, the Proto-Tethys ocean's evolution and the Early Palaeozoic orogeny.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2833-2848"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stability Analysis and Mitigation Measures for Slope Failure: A Case Study at Lalpani in District Shimla, Himachal Pradesh, India","authors":"Kanwarpreet Singh,&nbsp;Gaurav Juneja,&nbsp;Abhishek Sharma,&nbsp;Sahil Sharma,&nbsp;Aditya Kumar Tiwary,&nbsp;Sahil Kumar,&nbsp;Vineet Pandey","doi":"10.1002/gj.70110","DOIUrl":"https://doi.org/10.1002/gj.70110","url":null,"abstract":"<div>\u0000 \u0000 <p>Due to unprecedented rainfall in Shimla District of Himachal Pradesh, India several critical slopes were damaged in the rainy season and the sewerage treatment plant located at Lalpani, District Shimla was among one of them. In order to uncover the variables, responsible for the periodic slope collapse, an integrated geotechnical and numerical endeavour is needed service of past stability assessments. Geotechnical investigation reveals relevant soil properties that influence stability. The correlation between rain and slope collapse could be described numerically as an event specific antecedent rainfall threshold. A two-dimensional LEM (limit equilibrium method) approach to show the slope's stability before and after failure has been employed in present work. The static and dynamic analysis was performed to find the critical failure surface and calculating its Factor of Safety (FOS). The Lalpani slope was significantly stabilised due to the implementation of self-drilling anchors and RCC retaining walls. The slope first failed without self-drilling anchors and/or an RCC retaining walls and requested an analysis for the slope with reported Factor of Safety (FOS) &lt; 1. The addition of self-drilling anchors and RCC retaining walls resulted in and increased FOS = 1.68 for slope-1 and 1.58 for slope-2; both having FOS's greater than the commonly accepted critical value of 1.5. Clearly, the proposed stabilising design retained the original slope configuration that would permanently stabilise the slope and allow for sustainability of slope for the foreseeable future and sustainable success for slope safety.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2703-2720"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Sources of Diagenetic Fluids and Diagenetic Evolution Model in Deep-to-Ultra-Deep Tight Sandstone Reservoirs: A Case Study From Bashijiqike Formation, Kalesu Belt, Kuqa Depression, Tarim Basin, NW, China","authors":"Rui Wang,&nbsp;Wenzhe Gang,&nbsp;Zhilong Huang,&nbsp;Xiaobo Guo,&nbsp;Yongshuai Pan,&nbsp;Libin Zhao,&nbsp;Tao Mo","doi":"10.1002/gj.70112","DOIUrl":"https://doi.org/10.1002/gj.70112","url":null,"abstract":"<div>\u0000 \u0000 <p>The origin and evolution of diagenetic fluids in deep to ultra-deep reservoirs are complex and critical for understanding reservoir quality. Based on the conventional formation water analysis, this study investigates the sources and effects of diagenetic fluids in the Cretaceous reservoirs of the Kelasu structural belt, Kuqa Depression, NW China, integrating analyses of carbonate cement carbon and oxygen isotopes, rare earth elements (REEs), fluid inclusion homogenization temperatures, thin section petrography, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results show that formation water is generally characterized by slightly enriched Na⁺ + K⁺, high Ca²⁺, and low Mg²⁺ and SO₄\u0000 ²⁻ concentrations. Ion ratio coefficients indicate strong water–rock interactions and good sealing conditions in both areas. The high salinity of the formation water is mainly controlled by seawater evaporation, evaporite (especially salt rock) dissolution, and water–rock interactions. Carbon and oxygen isotopic and REE data suggest multiple sources of diagenetic fluids, including meteoric water, seawater or saline lake water, low-salinity organic acid fluids, and gypsum-derived diagenetic water. Diagenetically, BBZ experienced early shallow burial followed by rapid deep burial, which helped preserve primary porosity. In contrast, the DDB underwent continuous deep burial, resulting in stronger compaction and lower porosity. Carbonate cementation and clay mineral transformation occurred earlier in the DDB than in the BBZ. These findings reveal significant spatial differences in fluid origin and diagenetic processes that control reservoir properties in deep tight sandstone reservoirs.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2746-2769"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148910038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Holocene Climatic Record in the Northeastern Part of the Deccan Trap Region, Maharashtra, India: Episodic Intensification and Weakening of the Monsoon","authors":"B. V. Lakshmi,&nbsp;K. Deenadayalan,&nbsp;Manan Singh,&nbsp;Pradnya Mohite,&nbsp;Garima Shukla,&nbsp;A. P. Dimri","doi":"10.1002/gj.70120","DOIUrl":"https://doi.org/10.1002/gj.70120","url":null,"abstract":"<div>\u0000 \u0000 <p>A high-resolution paleoclimatic reconstruction from the Tirna River basin in the Deccan Volcanic Province (DVP) of western India, covering about 2022 - 1596 calibrated years BP, is presented in this paper. The study combines magnetic susceptibility (χ) and elemental geochemistry ratios (Fe/Al, Ti/Al, K/Na, K/Al, Ca/Al, Mn/Al, and Mg/Al) to infer weathering regimes, detrital input patterns, and sedimentary processes controlled by climate. An initial wet and erosive period (~1596–1707 cal yr. BP) characterised by high Fe/Al, Ti/Al, and χ values, reflects intense monsoon-driven detrital input, and represents one of the several climatic sequences captured in the record. A transitional period with decreasing magnetic susceptibility and Fe/Al ratios (~1722–1785 cal yr. BP) follows, indicating reduced runoff and possible monsoon variability. When chemical weathering markers peak between 1840 and 1872 cal yr. BP, it suggests a humid period with more intensified pedogenesis. Declining χ and subsequent increases in Ca/Al and Mg/Al (~1903–1974 cal yr. BP) indicate reduced erosion and a shift towards warmer and more stable conditions. A shift to cooler, drier, and more stable environmental conditions is indicated by the rapid fall in weathering proxies and χ during the most recent phase (~1993–2022 cal yr. BP). These climate changes are consistent with known regional and global paleoclimatic events, including the beginning of the Dark Ages Cold Period, the end of the Roman Warm Period, and the well-documented monsoon weakening event around 2.0 ka BP. The results demonstrate sensitivity of the DVP landscape to variations in the Indian Summer Monsoon. Overall, this study highlights the value of multi-proxy sediment records for reconstructing past monsoon variability and enhances our understanding of Late Holocene hydroclimatic dynamics in peninsular India.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2919-2939"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Integrated Geophysical Approach for the Precise Delineation of Sulphide Ore Within Fractured Zones of the Southern Benue Trough, Southeastern Nigeria","authors":"Chibuike Akpa,&nbsp;Charles Chibueze Ugbor,&nbsp;Kalu Mosto Onuoha,&nbsp;Chidiebere Chukwu Ani,&nbsp;Ikenna Arisi Obasi","doi":"10.1002/gj.70115","DOIUrl":"https://doi.org/10.1002/gj.70115","url":null,"abstract":"<div>\u0000 \u0000 <p>Given the need to reduce the proliferation of abortive mines, delineate the frontiers of the mineralised zone, and prioritise the presiding structural attributes of the sulphide ore deposits within the Benue Trough, this study integrated electrical resistivity tomography (ERT), induced polarisation (IP) and ground magnetic methods to characterise the litho-structural attributes significant for precise delineation of the lead-zinc deposits hosted by the fractured sedimentary rocks. The magnetic result delineated the major structural framework constituting NE–SW, NW–SE, N–S and E–W with the dominance of NE–SW and NW-SE structures dipping easterly and westerly, respectively. Their interpolation with the active-productive mines designated NW-SE structures trending ≥ 300° N with a high dip of up to 60°, and a few N–S structures to be mineralised. High magnetic anomaly closures predominantly trending in the NE–SW direction corresponded with mapped basic-intermediate intrusive rocks in the area. These structural trends guided the layout of the ERT and IP profiles in the E–W direction. In the mineralised zones, the ERT and IP signals indicated significantly low resistivity and high chargeability values, whereas the host rock exhibited high resistivity and poor chargeability responses. The ERT and IP signatures further characterised two main ore horizons and zoning: the shallow and deep emplaced lodes with average depths of 35 and 60 m, respectively. The 2D and 3D models revealed subsurface inhomogeneity and conduit-like geometry of the orebody corresponding to NW-SE trending structures. The mineral zoning and complex structural framework observed in the area suggest variable thermal regimes, micro-alteration in hydrothermal fluid composition and polyphase tectonic-magmatic activities in the Benue Trough.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2812-2832"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of Pore-Throat Combination Types and Pore-Throat Structure on the Seepage Capacity in Tight Sandstone Reservoirs: A Case Study of the Yanchang Formation in the Southeastern Yishan Slope of Ordos Basin","authors":"Zhuo Han,&nbsp;Zhanli Ren,&nbsp;Yanan Zhou,&nbsp;Bing Zhang,&nbsp;Zhendong Gao,&nbsp;Xuefeng Liu,&nbsp;Yiqian Qu,&nbsp;Jian Ren,&nbsp;Kai Qi,&nbsp;Ruiyang Chai,&nbsp;Ziyuan Meng,&nbsp;Hanning Wu","doi":"10.1002/gj.70119","DOIUrl":"https://doi.org/10.1002/gj.70119","url":null,"abstract":"<div>\u0000 \u0000 <p>The physical properties of throats, including the size, shape and combination types with pores, are essential for hydrocarbon migration pathways within the tight sandstone reservoirs; therefore significantly affecting the seepage capacity of tight oil. In the Ordos Basin, the Chang 6 member of the Triassic Yanchang Formation developed typical tight sandstones, which underwent various complex diagenetic processes following sedimentation, resulting in a complex pore-throat structure. To analyse the mechanism by which pore-throat combination types control the production and development of tight oil, systematic experiments were conducted on the Chang 6₃ sublayer samples in the southeastern Yishan Slope. According to the results of cast thin section (CTS), scanning electron microscopy (SEM), we suggest that the main pore types are feldspar intergranular dissolution pores and feldspar intragranular dissolution pores. Primary throat types include sheet-like, curved sheet-like and clay-mineral-filled bundle-like throats. The tight samples of the study area were classified into three typical types based on the results of high-pressure mercury injection (HPMI) and constant rate mercury injection (CRMI). For all samples (Type I–III), mercury injection saturation of the throat exceeds the pore, indicating that the throat controls the reservoir quality. From Type I to III samples, the pore volume progressively decreases while the throat volume increases correspondingly. Notably, Type III samples exhibit the exclusive development of throat networks, with the complete absence of pores. Meanwhile, by applying fractal theory, the pore-throat structures exhibit three-stage fractal characteristics with inflexion point radius <i>r</i>\u0000 _t1 and <i>r</i>\u0000 _t2: large pores (P_L), &gt; <i>r</i>\u0000 _t2, resembling bead-string-network structures; medium pores (P_M), between <i>r</i>\u0000 _t1 and <i>r</i>\u0000 _t2, transitional between bead-string-network structures and capillary-tree-like structures; and small pores (P_S), &lt; <i>r</i>\u0000 _t1, similar to capillary-tree-like structures. Samples with smaller <i>r</i>\u0000 _t1 and larger <i>r</i>\u0000 _t2 have better-connected pore-throat networks, and higher P_M proportions contribute to better reservoir quality. The bead-string model has the greatest impact on permeability and mercury saturation, while P_L and P_M dominate porosity, P_M controls permeability and P_S (nanoscale, mercury-impenetrable) pores barely impact permeability. Our results could provide theoretical guidance for improving the recovery rate of tight oil reservoirs.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 9","pages":"2899-2918"},"PeriodicalIF":2.6,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}