Journal of Palaeogeography最新文献

{"title":"Provenance of the Devonian Liuling Group sandstones: Constraints on Paleozoic North–South China Block tectonics","authors":"Lei-Gang Zhang,&nbsp;Hong-Jun Qu,&nbsp;Peng Li","doi":"10.1016/j.jop.2025.100264","DOIUrl":"10.1016/j.jop.2025.100264","url":null,"abstract":"<div><div>The Devonian Liuling Group (DLLG) and its surrounding strata provide massive information about the Paleozoic subduction–suture–extension process of the North China Block (NCB) and South China Block (SCB). Systematic field-based sedimentology, sandstone modal composition, whole-rock elemental composition, and detrital zircon U–Pb dating were employed. The sedimentary sequence of DLLG shows that the water depth deepened and then shallowed, which is characteristic of an extensional basin. Analysis of the tectonic setting and geochronology revealed that the fore-arc sedimentary system (FAS) and DLLG were sourced from the North Qinling Belt (NQB) and NCB. An age population with a single peak at 420 Ma from the FAS suggests that the island arc existed at 420 Ma, indicating that the subduction of the Shangdan Ocean did not finish until the late Silurian. The DLLG deposits were mainly from basement material of the NQB, indicating that the Shangdan Ocean closed before the Middle Devonian, which implies that the NQB and South Qinling Belt (SQB) were spliced during the Early Devonian. This rapid transition from subduction to extension and the absence of molasse hint that no full orogeny occurred during the suture process and that the DLLG formed in a post-suture extensional rift basin.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100264"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentary architecture characterization by combining well logs and seismic data in river-dominated delta reservoirs: the Pearl River Mouth Basin, South China Sea","authors":"Hong-Hui Li ,&nbsp;Da-Li Yue ,&nbsp;Wei Li ,&nbsp;Ling-Ling Dan ,&nbsp;Yuan Liu ,&nbsp;Wu-Rong Wang ,&nbsp;Ke-Yu Ren ,&nbsp;Ling Tan","doi":"10.1016/j.jop.2025.03.004","DOIUrl":"10.1016/j.jop.2025.03.004","url":null,"abstract":"<div><div>In offshore fields with limited well data, intricate geological configurations, and high reservoir heterogeneity, the accurate prediction of sand body distribution and characterization of sedimentary architecture pose significant challenges due to inherent geological uncertainties and data limitations. This study employs a comprehensive approach integrating three key methods to enhance prediction accuracy: (i) fusion of spectral-decomposed seismic attributes, (ii) seismic attribute fusion of target and neighboring zones, and (iii) colored seismic inversion. The first method leverages seismic information across various frequencies, yielding reliable results for sand bodies of different thicknesses. The second method mitigates the impact of seismic responses from adjacent zones on sand body predictions, making it particularly suitable for target intervals where neighboring zones significantly influence the seismic response. The third one, colored seismic inversion enhances the prediction of vertical distribution and the stacking relationships of sand bodies. These methods have been applied in an oilfield in the Pearl River Mouth Basin, southern China. Consequently, the sedimentary architecture of a braided river delta reservoir is successfully characterized, leading to the identification of four distributary channels within a depositional Zone 1 of the Zhujiang Formation. Additionally, a comprehensive workflow integrating well logs, seismic data, and depositional models significantly improves predictions of sand body distribution and sedimentary architecture in complex geological settings, providing critical geological insights for optimizing subsequent oilfield development strategies.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100249"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The significance of benthic ecospace expansion following the ROECE at the Cambrian Series 2–Miaolingian boundary, western Henan Province, central China","authors":"Da Li,&nbsp;Jian Fu,&nbsp;Yong-An Qi,&nbsp;Xi-Tong He,&nbsp;Man Li,&nbsp;Fu-Qiang Guo","doi":"10.1016/j.jop.2025.100256","DOIUrl":"10.1016/j.jop.2025.100256","url":null,"abstract":"<div><div>The transition period from the Cambrian Series 2 to Miaolingian was a pivotal juncture in Earth's history, marking the onset of significant shifts in biodiversity and biomass dynamics during the Phanerozoic. Concurrently, profound transformations occurred in the alteration of sedimentary deposits by trace makers, reshaping benthic ecological spaces. This study employs ichnological and ecological methodologies to construct a comprehensive three-dimensional spatial model for ecospace occupation and ecosystem engineering within the Mantou Formation in the western Henan Province, focusing on the transition between the Cambrian Series 2 and Miaolingian. A meticulous statistical analysis of 22 ichnogenera and 32 ichnospecies in the Mantou Formation revealed nuanced variations, such as a decrease in the proportion of predatory organisms in the lower part of Member 2 of the Mantou Formation and a corresponding increase in the upper part. Simultaneously, non-selective deposit-feeding animals exhibit an ascending trend in the lower part of Member 2 and a descending trend in the upper part of Member 2.</div><div>In terms of sediment bioturbation, the lower part of Member 2 is characterized by the exclusive presence of biodiffusors and conveyors, whereas regenerators make their appearance in the upper part of Member 2. Affected by the Redlichiid–Olenellid Extinction Carbon isotope Excursion (ROECE) event, metazoans experienced a shift in control dynamics, with microbial mats becoming dominant. Biological activities became intricately intertwined with microbial mats. In the upper part of Member 2, metazoans started recovering, concomitant with the emergence of <em>Thalassinoides</em> and <em>Treptichnus</em> substantially boasting ecosystem engineering impact (EEI) values. These trace makers rapidly amplified the depth and extent of sediment disturbance, giving rise to a profusion of novel ecological niches and catalyzing the transformation of builder functional groups.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100256"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentology, sequence stratigraphy and geochemical reappraisal of the Mesoproterozoic Rampur Shale, Vindhyan Basin, India: Implications for paleoenvironment and basin evolution","authors":"Indrani Mondal ,&nbsp;Adrita Choudhuri ,&nbsp;Tathagata Roy Choudhury ,&nbsp;Shilpa Srimani ,&nbsp;Amlan Koner ,&nbsp;Sunipa Mandal ,&nbsp;Subir Sarkar","doi":"10.1016/j.jop.2025.100259","DOIUrl":"10.1016/j.jop.2025.100259","url":null,"abstract":"<div><div>This paper investigates the sedimentology and geochemistry of the black shale deposit of the Rampur Shale Member and interprets the depositional environment, the provenance of the sediments, and the paleoclimatic and paleo-redox conditions to elucidate the evolution history of the Vindhyan Basin in central India during the Mesoproterozoic time. The Rampur Shale Member consists of five facies, representing a fining-upward succession dominated by a coarse-grained sandstone-siltstone alternation at the basal part with an increasing shale content towards the top, culminating into a black shale deposit. Process-based facies analysis documents the shift in the depositional environment from the lower shoreface to the outer part of the continental shelf, suggesting a basin-wide marine transgression which resulted in the deposition of the black shale within the maximum flooding zone (MFZ). Abundant organic matter, with δ¹³C_org values ranging between −25‰ and −34.30‰, preserved in the form of the crinkly laminated, lensoidal, and spheroidal-shaped microbial mat growth on the sediment surface contributes to the characteristic dark hue of the black shale, which is further supplemented by the high TOC (Total Organic Carbon) content of the black shale. Several geochemical proxies suggest that the sediments were sourced predominantly from felsic igneous provinces; however, increased contributions from mafic sources were recorded during the later stages of deposition. The weathering intensity was high, and the black shale was deposited under humid climatic conditions. The paleoredox proxies suggest predominantly anoxic depositional conditions, most likely forming via organic matter degradation. The paleosalinity remained low due to the epicontinental nature of the basin, possibly as a consequence of dilution by freshwater influx from the basin margin. The trace metal proxies suggest the prevalence of upwelling conditions, perhaps resulting in the increased bio-productivity during the black shale deposition. Numerous slide planes at successive intervals bear the signature of basin subsidence and deepening, facilitating basin-wide black shale formation.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100259"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbially induced sedimentary structures (MISS) from Paleoproterozoic siliciclastic successions and their bearing on shallow marine sedimentation: Bayana Basin, North Delhi Fold Belt, India","authors":"Rahul Bailwal,&nbsp;Partha Pratim Chakraborty","doi":"10.1016/j.jop.2025.04.001","DOIUrl":"10.1016/j.jop.2025.04.001","url":null,"abstract":"<div><div>An attempt has been made to document Microbially Induced Sedimentary Structure (MISS) from siliciclastic strata of the Nithar and Badalgarh Formations, Paleoproterozoic Raialo and Alwar groups of rocks in the Bayana Basin of NW India. Whereas in the Badalgarh Formation MISS are documented from shallow marine foreshore-upper shoreface succession, in the Nithar Formation, the features are recorded from fluvial deposits where the river system attained local stagnation. Unlike the dominant description of Precambrian shallow-marine MISS from sub-tidal settings, the present description highlights MISS from foreshore-upper shoreface deposits of the Badalgarh coastline. MISS are documented from field study (bedding surface) and are further proved by microscope study of thin sections. The bedding surface features include wrinkle marks, palimpsest ripple, patchy ripple, gas dome structure, desiccation cracks, and erosional remains, whereas under microscope, wavy crinkly microbial laminae with frayed edges, trapping of fine detritus in microbial filaments, flying paper effect and disseminations/clots of pyrite, in association, are documented. The biogenicity of the crinkly laminae is further checked by Raman Spectroscopy. The documented microbial structures are grouped under three categories, namely mat growth and stabilization, mat destruction, and mat burial. The Badalgarh coastline records shallowing-upward normal regressive depositional trend. In conjunction with earlier descriptions of MISS from Paleoproterzoic and Neoproterozoic successions of central and western India, the present study from northwest India establishes an overwhelming microbial influence on Precambrian siliciclastic sedimentation in Indian basins.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100253"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dolomitization history and porosity evolution of the deeply buried Cambrian Xixiangchi Formation, Sichuan Basin, SW China","authors":"Zhuang-Zhuang Bai ,&nbsp;Shu-Yuan Shi ,&nbsp;Yong-Jie Hu ,&nbsp;Wei Yang ,&nbsp;Wu-Ren Xie ,&nbsp;Wen-Zheng Li","doi":"10.1016/j.jop.2025.100258","DOIUrl":"10.1016/j.jop.2025.100258","url":null,"abstract":"<div><div>The deeply buried (&gt;4500 m) Cambrian Xixiangchi Formation in the Sichuan Basin, southwestern China, hosts significant reserves of natural gas. A comprehensive analysis combining petrographic, paleo-thermometric, geochemical, and petrophysical materials of the dolostone from the Xixiangchi Formation was conducted to provide insight into deeply buried carbonate reservoirs and decipher the complex diagenetic history. Dolomite-mudstone, fine-crystalline dolostone, and fine-crystalline dolomite cement of the Xixiangchi Formation underwent sabkha and reflux dolomitization. Medium- to coarse-crystalline dolostone, dolo-grainstone, and medium- to coarse-crystalline dolomite cements were then formed by burial dolomitization. These dolomites display δ¹³C ratios and REE patterns comparable to seawater, with progressively depleted δ¹⁸O ratios at greater burial depths. Dolo-grainstone originating from the platform shoal facies exhibits higher primary porosities and well-developed inter-particle pores compared to dolo-mudstone and crystalline dolostone lithologies, which are typically associated with the low-energy tidal flat and/or restricted platform environments. The initial spatial heterogeneity of primary porosity was subsequently modified by meteoric alteration and repeated episodes of dolomitization, which contributed to the development of secondary porosity. These processes increased the resistivity to compaction, and open fractures increased reservoir permeability. During the deep burial regime, saddle dolomite and calcite cements were precipitated at high fluid temperatures (up to 220 °C). Thermochemical sulfate reduction is characterized by the occurrence of anhydrite, hydrocarbon, and high homogenization temperatures and significantly low δ¹³C ratios (av.=−23.7‰) of calcite cements. Deep burial dissolution is significantly constrained by: corrosion of late diagenetic minerals, and the occurrence of bitumen in the center of pores. Mechanisms for the deep-burial dissolution include hydrothermal alteration and thermochemical sulfate reduction. This study indicates the complex diagenetic evolution of Cambrian Xixiangchi Formation, providing significant insights into global deep-burial carbonate reservoir potential.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100258"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Lower Miocene Askazansor Formation in Central Kazakhstan: Paleontological characteristics, biostratigraphy and paleogeographical conditions","authors":"Saida Nigmatova,&nbsp;Bolat Bayshashov,&nbsp;Ilnura Madiyarova,&nbsp;Arman Seidali,&nbsp;Balzhan Kalibek","doi":"10.1016/j.jop.2024.09.005","DOIUrl":"10.1016/j.jop.2024.09.005","url":null,"abstract":"<div><div>This manuscript provides valuable insight into the geological evolution of Central Kazakhstan during the Cenozoic and serves as a key tool for understanding the paleogeographic evolution of the surrounding regions. Based on the literature and the results of our own research, data on the Oligocene-Early Miocene fauna of the Askazansor site, located in the southern part of Central Kazakhstan, were analyzed and summarized. The stratigraphy was examined, the history of the research was studied, and an attempt was made to synchronize the paleofauna with other localities in Kazakhstan and Eurasia. The article presents descriptions of bone remains of previously unknown equids from here. The age of the deposits is considered to be the Early Miocene. Based on the study of mammals and the lithofacial analysis of sediments, conclusions were drawn about the paleoecological situation of this time.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100244"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbially-dominated Cambrian (Miaolingian) carbonate reef of the North China","authors":"Ming-Xiang Mei ,&nbsp;Muhammad Riaz ,&nbsp;Ardiansyah Koeshidayatullah ,&nbsp;Zi-Liang Liu","doi":"10.1016/j.jop.2025.03.003","DOIUrl":"10.1016/j.jop.2025.03.003","url":null,"abstract":"<div><div>The Miaolingian Series is a distinctive lithostratigraphic unit within the Cambrian System, characterized by the abundance of non-laminated dendrolites relative to stromatolites. During the Miaolingian Epoch, the North China Platform was marked by a pervasive development of ooid banks (more than one million km²) along with large and small bioherms associated mainly with sea-level fall. The North China Platform, exemplified by the Huolianzhai section, serves as a paradigm for deciphering the microbial composition and the sedimentary architecture of microbial carbonates that developed in the normal regression phase of third-order sea level changes. Carbonate reefs (biohermal-type structures) in this section comprise a high density of calcified sheaths of filamentous cyanobacteria together with <em>Epiphyton</em>. The microbial carbonate may result from sophisticated calcification of extracellular polymeric substances (EPS) that form multiple biofilms in relatively thick microbial mats dominated by cyanobacteria. The presence of the dolomitic crystals within dense micrite of microbial carbonates, such as thrombolite, leiolite, stromatolite along with potential fossilized cyanobacterial spores embedded within clotted micrite of the thrombolitic leiolites, has sparked both interest and intrigue. These findings underscore the complex and enigmatic origins of microbial carbonates which are interpreted to have been predominantly influenced by cyanobacterial activity. This study provides valuable insights into the formation of microbial carbonates, with implications for similar geological settings worldwide.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100248"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enigmatic large-toothed Campanian polycotylid plesiosaurs with specific dietary preferences and potentially wide distribution","authors":"Nikolay G. Zverkov ,&nbsp;Igor A. Meleshin","doi":"10.1016/j.jop.2024.11.007","DOIUrl":"10.1016/j.jop.2024.11.007","url":null,"abstract":"<div><div>Most polycotylid plesiosaurians have isodont dentition with relatively small and slender conical teeth. However, large and robust caniniform teeth are known for some of their basal late Albian and early Cenomanian representatives, implying greater ecological diversity early in the evolutionary history of the clade. Here we report the first evidence of polycotylids with large teeth in the Campanian, thus c. 15 Myr younger than previous records. Several teeth with crowns exceeding 40 mm in height and some reaching 25 mm in basal diameter were collected from two Campanian localities in European Russia. These are the largest polycotylid teeth reported from the Cretaceous of Eurasia. Their large size and specific enamel ornamentation markedly differ from other known polycotylid teeth, suggesting that these teeth belong to an undescribed taxon. However, similar enamel ornamentation was previously reported for the now forgotten ‘<em>Piratosaurus plicatus</em>’ Leidy, 1865 from the Upper Cretaceous of Canada, which may indicate the wide distribution of polycotylids with such teeth in the latest Cretaceous. Unlike classical polycotylids, the new teeth have strong apical wear which implies consumption of abrasive prey, similar to modern killer whales that feed on sharks. Thus, our finding reveals higher ecological diversity of polycotylids in the latest Cretaceous, suggesting the coexistence of small-to medium-toothed and large-toothed (probably ‘latirostrine’) taxa at different times of the evolutionary history of the Polycotylidae.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100254"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lacustrine delta-offshore bar system: depositional characteristics and formative mechanism","authors":"Chang-Ni Liu ,&nbsp;Sheng-He Wu ,&nbsp;Zhen-Hua Xu ,&nbsp;Qi Ren ,&nbsp;Da-Li Yue ,&nbsp;De-Gang Wu ,&nbsp;Yi-De Sun ,&nbsp;Wen-Fu Cui ,&nbsp;Ke-Li Li","doi":"10.1016/j.jop.2025.100267","DOIUrl":"10.1016/j.jop.2025.100267","url":null,"abstract":"<div><div>The lacustrine delta-offshore bar system serves as a critical hydrocarbon reservoir, in which sedimentary processes and depositional characteristics reflect a complex interplay of hydrodynamic, sedimentological, and geomorphic dynamics. Notably, such systems with their full suite of morphological attributes have not been numerically simulated prior to this study. Our Delft3D simulation has successfully reproduced the delta-offshore bar system for the first time, providing a tool to quantitatively analyze its depositional processes and stratigraphic signatures. Three new perspectives are proposed: 1) Three distinct hydrodynamic reaches of the system are recognized by hourly-averaged seaward flow velocity and hourly-averaged water level: fluvial-dominated reaches (positive seaward flow velocity and water level); interaction reaches (both nearly zero); and wave-dominated reaches (negative seaward flow velocity despite sustained positive water level). Deltaic front and offshore bars develop simultaneously in fluvial-dominated and wave-dominated reaches, respectively, which are separated by an interaction reach. They exhibit distinct morphological and depositional characteristics resulted by different depositional processes. 2) Partially submerged offshore bars form near the breaker zone in the wave-dominated reaches, originating from thin and submergent longshore shoreface. Initially, two offshore bars form on both sides of the longshore shoreface through vertical accretion, then they experience elongation and merge into a large-scale bar through lateral accretion, and finally continue to widen through landward accretion. 3) Deltas are confined to the fluvial-dominated reaches, extending to a certain length with a low length-to-width ratio and a smooth shoreline, featuring rare sinuous distributary channels before the formation of the large-scale offshore bar. Once the large-scale offshore bar forms, deltas continue to prograde basinward. The results of this study have been applied to reservoir characterization, improving the identification of single sand-bodies and internal accretions in Member 2 of the Paleogene Shahejie Formation, Shengtuo Oilfield, Bohai Bay Basin, China.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100267"},"PeriodicalIF":0.0,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}