Geological Journal最新文献

{"title":"Very Low-Grade Metamorphism and Paleogeothermal Recovery of the Upper Palaeozoic in the Suhongtu Depression, Yin-E Basin, North China: Constraints From Illite, Vitrinite Reflectance, and Fluid Inclusions","authors":"Jian Liu,&nbsp;Zhanli Ren,&nbsp;Kai Qi,&nbsp;Guoliang Ma,&nbsp;Fan Sang,&nbsp;Yanzhao Liu,&nbsp;Zhuo Han","doi":"10.1002/gj.70049","DOIUrl":"https://doi.org/10.1002/gj.70049","url":null,"abstract":"<div>\u0000 \u0000 <p>The Yin-E Basin, located at the junction of the Siberian, Kazakhstan, and Tarim blocks and the North China Craton, has experienced complex tectonic activities and remains one of the underexplored onshore sedimentary basins in China. The Upper Palaeozoic is an important stratigraphic interval for oil and gas exploration, but its source rock thermal evolution lacks systematic research, thus hindering exploration progress. Addressing the frontier topic of very low-grade metamorphism's role in organic maturation, we studied the clay mineralogy (illite crystallinity: 0.42°–0.25° Δ2<i>θ</i>), illite polymorphism (predominantly 2 M1), and cell parameters (b₀: 9.0024–9.0204 Å) of the Upper Palaeozoic source rocks (wells YBC1, BD1 and YBN1) in the Suhongtu Depression, revealing the palaeogeothermal field of the Upper Palaeozoic. These data were combined with basin modelling to quantitatively constrain the thermal evolution history. The results indicate that the Upper Palaeozoic strata primarily underwent prehnite-pumpellyite-facies of very low-grade metamorphism under medium-low pressure, corresponding to peak temperatures of 211.94°C–226.32°C. The reconstructed palaeotemperature reached 210°C–220°C. By the end of the Permian, all source rocks had reached their maximum thermal maturity (vitrinite reflectance, <i>R</i>o: 1.42%–2.42%), with the Ba'nan Sag showing significantly higher maturity (<i>R</i>o: 1.57%–2.42%). This study provides key constraints on the thermal evolution and hydrocarbon generation potential of Upper Palaeozoic source rocks, supporting future exploration in the Yin-E Basin and adjacent areas.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1556-1574"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174309","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":"Depositional Architecture, Paleoenvironmental Dynamics and Hydrocarbon Potential of the Jurassic Da'anzhai Member, Sichuan Basin: A Comprehensive Sequence Stratigraphic and Geochemical Analysis","authors":"Minglong Li,&nbsp;Shengyang Xie,&nbsp;Zikun Zhou,&nbsp;Xingzhi Wang,&nbsp;Lin Xie,&nbsp;Yaping Wang,&nbsp;Bo Li,&nbsp;Deming Zeng,&nbsp;Jiahao Kang,&nbsp;Yihao Guo,&nbsp;Rui Zhang","doi":"10.1002/gj.70054","DOIUrl":"https://doi.org/10.1002/gj.70054","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;The Early Jurassic Da'anzhai Member of the Ziliujing Formation, located in the Sichuan Basin, represents a key stratigraphic unit for unconventional hydrocarbon exploration due to its organic-rich facies and favourable depositional conditions. This study employs an integrated approach, combining lithofacies analysis, sequence stratigraphy and high-resolution paleoenvironmental reconstruction, to investigate the factors governing organic matter accumulation and to identify prospective exploration targets. Previous studies, supported by sedimentary and geochemical evidence, classify the Da'anzhai Member as a nonmarine lacustrine deposit, which is further categorised into three facies associations: marginal, shallow and semi-deep lacustrine. These are differentiated based on a combination of sedimentary structures formed by wave- and current-generated structures, fossil assemblages and lithological variations, all of which reflect differences in depositional energy and water depth relative to the wave base. A third-order sequence stratigraphic framework was established comprising four systems tracts: Highstand Systems Tract 1 (HST1), Transgressive Systems Tract (TST), Highstand Systems Tract 2 (HST2) and Falling Stage Systems Tract (FSST). Within this framework, paleoenvironmental conditions evolved in response to changing climatic and hydrological regimes. Geochemical proxies revealed a transition from a relatively arid, shallow, and brackish lacustrine environment during HST1 to a deeper, fresher and highly productive anoxic lake during the TST, which peaked at the Maximum Flooding Surface (MFS). This was succeeded by complex highstand deposition (HST2), followed by a return to shallower, more evaporative conditions during the FSST. The entire sequence was interpreted as a terrestrial basin's response to the global Toarcian Oceanic Anoxic Event (T-OAE, ~183 Ma). This allocyclic climate-forced model suggests that the initial lacustrine transgression was driven by an intensified hydrological cycle associated with peak T-OAE warming, whereas the ensuing regression during the FSST corresponds to the global climate system's recovery phase. This climate-driven model has significant implications for hydrocarbon exploration in lacustrine shale systems. This climate-forced model has direct implications for hydrocarbon exploration. The primary geological ‘sweet spots’ were concentrated around the MFS, corresponding to peak transgressive conditions with optimal organic matter preservation. However, the most favourable engineering sweet spots were found at the TST/HST2 boundary. These zones provide an optimal balance of high organic content and improved fracability, resulting from lower concentrations of ductile calcite and higher concentrations of brittle minerals such as quartz and feldspar. Collectively, the integrated sequence-stratigraphic and palaeoenvironmental framework developed in this study not only refines understanding","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1638-1658"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174501","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":"Petrogenesis of Middle Triassic A2-Type Granitic Pluton in Shigongmiao Area, Hainan Island: Insights on Early Mesozoic Tectonic Evolution of South China Block","authors":"Gaofeng Du,&nbsp;Hao Xing,&nbsp;Dan Wang,&nbsp;Junling Pei,&nbsp;Jinfeng Wen,&nbsp;Xiatian Zhang,&nbsp;Songjian Lin","doi":"10.1002/gj.70050","DOIUrl":"https://doi.org/10.1002/gj.70050","url":null,"abstract":"<div>\u0000 \u0000 <p>The ongoing controversy regarding the Early Mesozoic tectonic regimes of Hainan Island (influenced by Paleo-Tethyan or Proto-Pacific dynamics) hinders a proper understanding of the geological evolution of the South China Block. A₂-type granites, typically associated with extensional environments, play a crucial role in addressing this issue as they form either in post-collisional or subduction-related extensional settings. In this study, we conducted a comprehensive analysis using whole-rock geochemistry, Sr-Nd-Pb isotopes, zircon U-Pb ages, and Hf isotopes on a Triassic granite from the Shigongmiao district on the east coast of Hainan Island. The new LA-ICP-MS U-Pb age reveals that the studied granites were emplaced in the Middle Triassic (U-Pb ages of ∼242 Ma), contemporaneous with the A-type granitic rocks distributed along the southeast coast of South China, which have ages ranging from ca. 230 to 250 Ma. Geochemically, these samples exhibit high SiO₂ (76.4–77.2 wt%), total alkalis (Na₂O + K₂O = 7.5–7.9 wt%), Ga/Al (&gt; 2.6), Rb/Nb (10.3–11.9), and Y/Nb (1.8–2.5), collectively supporting an A₂-type affinity for the Shigongmiao pluton. All samples consistently display enriched <i>ε</i>\u0000 _Nd(<i>t</i>) and <i>ε</i>\u0000 _Hf(<i>t</i>) values, along with old two-stage crustal Nd-Hf isotopic model ages (1.70–2.10 Ga) and high zircon Ti thermal temperatures (796°C–851°C). Geochemical and isotopic characteristics suggest that the Shigongmiao granites formed by partial melting of intermediate-felsic calc-alkaline granitoids under high-temperature, low-pressure conditions. Integrating regional geological data, we conclude that the Shigongmiao A₂-type granite originated in an extensional setting associated with Proto-Pacific plate subduction. This finding supports the existence of pre-existing continental arc magmatism along the southeastern margin of the South China Block during the Early Mesozoic era.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1575-1594"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174042","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":"High Heat Flow and Geothermal Opportunities in the Sunda Basin, Indonesia: A Case for Sustainable Energy Development","authors":"Luhut Pardamean Siringoringo","doi":"10.1002/gj.70046","DOIUrl":"https://doi.org/10.1002/gj.70046","url":null,"abstract":"<div>\u0000 \u0000 <p>Indonesia's geothermal development has traditionally focused on Quaternary volcanic arcs, as exemplified by power plants in Sibayak (North Sumatra), Salak (West Java), Kamojang (West Java), and Sarulla (North Sumatra). However, increasing socio-environmental challenges in densely populated regions highlight the need to explore alternative geothermal provinces. This study evaluates the geothermal potential of the offshore Sunda Basin using data from 21 oil wells. The results reveal heat flow values of 60–140 mW/m², geothermal gradients of 30°–70°C/km, and thermal conductivity ranging from 1.66 to 2.14 W/m °C—indicating favourable thermal conditions within sedimentary units. These characteristics are structurally supported by a thin crust (~30 km), normal faulting, and back-arc tectonic features formed during Tertiary-age slab rollback and pull-apart processes. Comparative analysis with global basins—including Gonghe, Upper Rhine Graben, Buyuk Menderes, Thrace, and Western Canada Sedimentary Basin (WCSB)—demonstrates that the Sunda Basin exhibits competitive geothermal characteristics, particularly in terms of accessible reservoir depth and thermal stability. The basin's offshore setting reduces typical onshore development constraints, offering a strategic opportunity for low-impact geothermal exploitation through re-utilisation of inactive oil wells and modular technologies. This study reinforces the Sunda Basin's role in diversifying Indonesia's geothermal portfolio and supporting national targets for net-zero emissions by 2060.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1501-1512"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174308","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":"Listriodon pentapotamiae From the Dhok Bun Ameer Khatoon, Siwaliks, Pakistan","authors":"Sharon Zulfiqar,&nbsp;Kiran Aftab,&nbsp;Muhammad Akbar Khan,&nbsp;Muhammad Adeeb Babar,&nbsp;Mubashar Hussain,&nbsp;Syed Zakir Hussain Shah","doi":"10.1002/gj.70052","DOIUrl":"https://doi.org/10.1002/gj.70052","url":null,"abstract":"<div>\u0000 \u0000 <p>New material of <i>Listriodon pentapotamiae</i> was recovered from Dhok Bun Ameer Khatoon, Chinji Formation of Siwaliks, Pakistan. This locality represents the Lower Chinji Formation with an estimated age of 14.2–13.2 Ma. The studied material includes an upper second incisor, upper second molars, and a well-preserved, complete mandibular fragment with c-m3, which is very elongated. These teeth are smaller compared to other genera of the family Suidae. I2 is small and chisel shaped, while in all molars, prominent lophs are present. These new findings advanced our understanding of the morphology of <i>Listriodon</i> within the Lower Siwaliks of Pakistan.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1610-1620"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174467","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":"RETRACTION: Economic and Social Impacts of the Green Energy Transition: A Pathway Towards 100% Renewable Energy Agenda","authors":"","doi":"10.1002/gj.70188","DOIUrl":"https://doi.org/10.1002/gj.70188","url":null,"abstract":"<p>\u0000 \u0000 <b>RETRACTION</b>: <span>L. Ma</span>, “ <span>Economic and Social Impacts of the Green Energy Transition: A Pathway Towards 100% Renewable Energy Agenda</span>,” <i>Geological Journal</i> <span>58</span>, no. <span>9</span> (<span>2023</span>): <span>3438</span>–<span>3451</span>, https://doi.org/10.1002/gj.4764.\u0000 </p><p>The above article, published online on 15 May 2023 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the author; the journal's Editors in Chief, Ian D. Somerville and Yunpeng Dong; and John Wiley &amp; Sons Ltd. The retraction has been agreed following concerns raised by third parties and at the author's request. A pattern of irrelevant citations has been observed, and further investigation by the publisher has identified concerns over the integrity of the peer review process. Accordingly, the article has been retracted.</p>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/gj.70188","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174466","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":"Can Energy Security Help Use Ecology More Efficiently in G7 Countries? A New Policy Guideline","authors":"Oktay Özkan,&nbsp;Victoria Olushola Olanrewaju,&nbsp;Adeola Praise Adepoju,&nbsp;Berna Uzun,&nbsp;Tomiwa Sunday Adebayo","doi":"10.1002/gj.70051","DOIUrl":"https://doi.org/10.1002/gj.70051","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, we explore, for the first time, how energy security (ESEC) impacts ecological efficiency (ECOE), providing valuable insights into the relationship between these two critical factors. This investigation is crucial as it addresses a gap in existing research, shedding light on how ESEC measures can enhance or hinder ecological outcomes. In this study, we use the G7 nations as a case study, analysing annual data from 1980Q1 to 2021Q4. To examine the relationship between ESEC and ECOE, we employ the novel quantile-on-quantile KRLS method, which allows for a thorough understanding of the dynamic interaction between these variables across different quantiles. The results from the study show that ESEC improves ECOE in the G7 nations, with the exception of Germany, which has a mixed relationship. Based on the study's results, it is recommended that G7 nations continue to prioritise ESEC as a means to improve ECOE, while considering tailored approaches for Germany, where the relationship between ESEC and ECOE shows positive effects at lower quantiles and diminishing effects at higher quantiles.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1595-1609"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174383","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 Impact of Democratization and Globalization on Environmental Sustainability in Brazil","authors":"Mustafa Naimoğlu,&nbsp;Mehmet Metin Dam,&nbsp;Serdar Ongan,&nbsp;Andrew Adewale Alola","doi":"10.1002/gj.70053","DOIUrl":"https://doi.org/10.1002/gj.70053","url":null,"abstract":"<p>Although Brazil still possesses significant ecological reserves, the surplus in its biocapacity has been rapidly declining in recent years. This study examines the relationship between environmental sustainability and key economic, political, and energy-related factors in Brazil from 1990 to 2018. The primary motivation behind the research is to explore the potential associations between Brazil's declining biocapacity and various economic and political dynamics, thereby providing insights that may inform sustainability efforts. The study tests the hypothesis that economic growth leads to environmental degradation or improvement, employing Fourier-augmented Dickey-Fuller and Fourier Autoregressive Distributed Lag (ARDL) approaches. The findings reveal that economic growth negatively impacts environmental sustainability in both the short and long term, rendering the Inverted Load Capacity Curve Hypothesis (ILCCH) invalid, as the long-term coefficient of economic growth is larger than the short-term one. Additionally, the study highlights that democratisation positively affects environmental sustainability, while economic globalisation exacerbates environmental conditions. Based on the findings, it is concluded that Brazil, as a resource-dependent economy, needs to reassess the environmental costs of its growth and globalisation strategies. The study emphasises the importance of aligning economic growth strategies with environmentally friendly policies to ensure sustainable long-term growth in Brazil.</p>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1621-1637"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/gj.70053","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174557","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":"Ultramafic to Mafic Cumulates From a Mesoarchean Accretionary Belt in Southern India","authors":"Yi-Miao Hong,&nbsp;M. Santosh,&nbsp;Cheng-Xue Yang,&nbsp;K. V. Sarath,&nbsp;Bing Yu,&nbsp;E. Shaji,&nbsp;Sanghoon Kwon","doi":"10.1002/gj.70055","DOIUrl":"https://doi.org/10.1002/gj.70055","url":null,"abstract":"<div>\u0000 \u0000 <p>The Mercara Suture Zone sandwiched between the Western Dharwar Craton and the Coorg Block, recently identified as a Mesoarchean suture, provides significant insight into the tectonics during early Earth history. The remnants of Archean oceanic lithosphere, which occur as ultramafic to mafic cumulates, were investigated for the first time in this study from the accretionary belt within the Mercara suture zone. With a view to gaining insights into the regional crustal evolution through Mesoarchean subduction–accretion-collision processes, in this study, we present petrology, whole-rock geochemistry including major, trace, and rare earth elements, and zircon U–Pb and Lu-Hf geochronology to trace the petrogenesis of the cumulates and associated rocks and the timing of magmatism. These mainly comprise hornblendite, amphibolite and metagabbro, with minor felsic rocks. The ultramafic to mafic cumulates display moderate SiO₂ (44.76–52.08 wt%), low Zr/TiO₂*0.0001 (0.001–0.007), and low to moderate ^TFeO/(^TFeO + MgO) (0.31–0.61), indicating their generation from magnesian, sub-alkaline basaltic magma. The chondrite-normalised and primitive mantle-normalised trace elements of the ultramafic-mafic cumulates show transitional features between normal mid-ocean ridge basalt (N-MORB) and enriched mid-ocean ridge basalt (E-MORB), while MORB-normalised trace elements display pronounced positive Pb anomaly and flat HREE patterns, suggesting oceanic backarc (OBA) and island arc tholeiite (IAT) affinities. Most of the cumulates display low to moderate V/Ti (0.05–0.08), low Nb/Zr (0.04–0.19) and moderate Zr (13.1–71.4 ppm), consistent with subduction settings. Most zircon grains in these rocks have ca. 3.1 Ga magmatic cores with metamorphic overgrowths at ca. 3.1–3.0 Ga. Zircon Lu–Hf analyses yield <span></span><math>\u0000 \u0000 <semantics>\u0000 \u0000 <mrow>\u0000 \u0000 <msub>\u0000 \u0000 <mi>T</mi>\u0000 \u0000 <mi>DM</mi>\u0000 </msub>\u0000 </mrow>\u0000 </semantics>\u0000 </math> ages of ca. 3.3 Ga with εHf(t) values in the range of −0.5 to 1.3, suggesting juvenile late Paleoarchean sources. Our study suggests that the ultramafic to mafic cumulates could be remnants of oceanic lithosphere preserved within the accretionary prism, as an archive of the Mesoarchean convergent margin processes.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1659-1682"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174749","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":"Ichnology and Palaeoenvironment Significance of the Tortonian Blue Marls Formation in the Southern Margin of the Lower Chelif Basin, Algeria","authors":"Ahmed Belhadji,&nbsp;Imad Bouchemla,&nbsp;Madani Benyoucef,&nbsp;Ahmed Zeghari,&nbsp;Sabiha Talmat,&nbsp;Ali Berrabah,&nbsp;Youcef Zemour","doi":"10.1002/gj.70062","DOIUrl":"https://doi.org/10.1002/gj.70062","url":null,"abstract":"<div>\u0000 \u0000 <p>This study integrates ichnological and sedimentological data to interpret depositional environments in the siliciclastic deposits of the Blue Marls Formation exposed along the southern margin of the Lower Chelif Basin, northwestern Algeria. The Formation is subdivided into two main units; the lower unit consists of sandstone beds exhibiting abundant but low-diversity trace fossils and various sedimentary structures, intercalated with marlstone intervals containing both planktonic and benthic foraminifera. In contrast, the upper unit comprises thick, massive, dark grey to green-grey marl deposits that are rich in planktonic foraminifera but devoid of ichnological records. Micropalaeoentological analysis of the planktonic foraminifera indicates that this succession was deposited during the Tortonian marine transgression, a well-documented event in the Lower Chelif Basin. The identification of the bioevent FO <i>Neogloboquadrina acostaensis</i> in the basal part of the formation enables its correlation with an age of approximately 10.55 Ma. Ichnological investigation of the detrital-dominated lower unit reveals 17 ichnotaxa, including <i>Arenicolites</i> isp. A, <i>Arenicolites</i> isp. B, <i>Conichnus conicus, Gyrolithes</i> isp., <i>Lockeia siliquaria, Macanopsis</i> isp., <i>Monocraterion tentaculatum, Ophiomorpha nodosa</i>, <i>Palaeophycus</i> isp., <i>Rosselia socialis, Rosselia</i> isp., <i>Skolithos annulatus</i>, <i>Sk</i>. <i>linearis</i>, <i>Sk</i>. <i>verticalis, Taenidium</i> isp., <i>Thalassinoides suevicus</i>, and <i>Thalassinoides</i> isp. This trace-fossil suite consists of mid- to deep-tier, predominantly vertical post-depositional burrows, ethologically dominated by domichnia (dwelling structures) produced by opportunistic suspension-feeding organisms such as decapod crustaceans and polychaete worms. The assemblage is attributed to the <i>Skolithos</i> ichnofacies, with only rare occurrences of elements indicative of a proximal <i>Cruziana</i> ichnofacies. It indicates high-energy conditions associated with storm events, good oxygenation, and abundant nutrient supply in both the water column and on the seafloor. Integrated sedimentological and ichnological analyses of the detrital-dominated deposits suggest deposition in a lower shoreface to offshore-transition setting, characterised by a wave-dominated depositional setting governed by storm-generated currents affecting macrobenthic communities and their lifestyle and surviving strategy.</p>\u0000 </div>","PeriodicalId":12784,"journal":{"name":"Geological Journal","volume":"61 6","pages":"1807-1831"},"PeriodicalIF":2.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148174748","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}