Depositional Record最新文献

{"title":"Disentangling the depositional, tectonic and diagenetic history of a unique case of rhombic calcite in marine carbonate scree-like deposits in the Cretaceous Cauvery Basin","authors":"Shilpa Srimani,&nbsp;Theresa Nohl","doi":"10.1002/dep2.70094","DOIUrl":"https://doi.org/10.1002/dep2.70094","url":null,"abstract":"<p>The Cretaceous Cauvery Basin along the eastern margin of India is associated with strong plume and rift-controlled tectonic activity, causing highly variable sediment successions under fast relative sea level changes. The ~60 m thick fossil-rich Kallankurichchi Formation comprises dominantly calcarenites, whereas its basal part contains mixed siliciclastic-carbonate scree-like conglomerates and dark grey limestone in the deepest section, possibly the result of a complex tectonic history. Due to the flow transformation, the clast-supported scree-like conglomerates grade into matrix-supported debris flow conglomerates. One unit of these matrix-supported debris flow conglomerates contains 6–14 μm sized calcite rhombs, which have not been previously reported for such deposits. Through integrated petrographic, geochemical and sedimentological analyses, we document the calcite rhomb formation and discuss their origin by either dedolomitisation or by meteoric diagenesis in shallow marine environments that were temporally subaerially exposed. The absence of any evaporites, absence of large quantities of originally high Mg components and absence of dolomite relicts limits the interpretation of dedolomite. Bored limestone clasts in the matrix-supported debris flow conglomerates, and the occurrence of fully marine species such as <i>Inoceramus</i> is generally interpreted as scree-like deposits in nearshore environments being deposited in fully marine conditions. An alternative explanation is tectonic uplift on one side of a fault causing scree deposits to accumulate in shallow marine environments, and subsequent subaerial exposure due to further uplift or a short interval of sea level fall, allowing infiltration of meteoric waters and rhombic calcite formation, followed by submersion. The findings imply a significant tectonic, post-depositional readjustment event, leading to localised meteoric diagenesis in an otherwise full marine depositional regime. This study documents the complex strata, discusses potential formation mechanisms of rhombic calcite in scree-like deposits and provides new insights into the interplay between diagenetic processes and basin tectonics.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70094","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149163198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"How life affects mineral formation: A reappraisal of concepts and terminology","authors":"Patrick Hadrian Meister,&nbsp;Nereo Preto","doi":"10.1002/dep2.70081","DOIUrl":"https://doi.org/10.1002/dep2.70081","url":null,"abstract":"<p>Numerous biological factors have been proposed to influence the formation of minerals under Earth-surface conditions, but the underlying concepts are often confused due to inconsistent terminology. The current systematics has largely developed historically, yet remains unclear because several terms have contrasting definitions or are not self-explanatory. Over time, the variety of processes proposed to explain biological effects on mineral formation has expanded, but the underlying mechanisms often remain far from fully resolved and sometimes lack a proof of concept. Here, a systematic framework of terms is proposed, requiring only slight modifications of the established terminology, primarily by removing some of the non-self-explanatory connotations. For example, the term ‘biologically influenced’ mineral formation better should represent a general ‘influence’ rather than a specific mechanism. In turn, ‘biologically induced’ should be used in its original meaning as ‘driven by supersaturation’. New terms such as ‘biologically nucleated’ and ‘biologically mediated’ precipitation would more precisely describe the specific mechanisms where organisms or biogenic organic substances act as a nucleation substrate or as a catalyst facilitating mineral growth from already supersaturated solution. The proposed scheme would necessitate minimal intervention into existing terminology and at the same time become more user friendly for broad application in sedimentology and biogeosciences. Establishing a coherent and canonical terminology will not only improve clarity but also provide a common ground for future research on how biological and abiotic factors influence mineral formation under Earth-surface conditions.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148994508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Geochemistry of low-temperature dolomite formation in coastal and continental saline to sabkha-like environments","authors":"Carlette N. Blok,&nbsp;M. Luis Gibert,&nbsp;Zeina Naim,&nbsp;Jordi Ibáñez-Insa,&nbsp;Mónica Sánchez-Román","doi":"10.1002/dep2.70084","DOIUrl":"https://doi.org/10.1002/dep2.70084","url":null,"abstract":"<p>Early diagenetic dolomite forms at low temperatures (&lt;50°C) in settings where relative contributions of microbial influences and pore-fluid chemistry are difficult to separate. Here, dolomite and associated aragonite, calcite and Mg-calcite from modern and ancient coastal and continental settings in Spain, Australia and Brazil were analysed using a multi-proxy geochemical approach. Scanning electron microscopy (SEM) images reveal filamentous structures, extracellular polymeric substances (EPS) and nanoglobules intergrown with the carbonate, consistent with microbial mediation nucleation. Stable carbon and oxygen isotope compositions (δ¹³C = −10.0–3.4‰; δ¹⁸O = −1.6–7.3‰) reflect variations in palaeoproductivity, temperature and hydrological regimes, and ⁸⁷Sr/⁸⁶Sr ratios (0.708213–0.709243) indicate fluid sources. Sr (up to 5828 ppm), Fe (up to 5187 ppm) and Mn (up to 1035 ppm) reach concentrations above those expected for equilibrium precipitation. Sr enrichment does not correlate with Mg/Ca, which we attribute to kinetically controlled uptake during rapid, microbially mediated growth rather than to equilibrium partitioning into the Ca lattice site. Mn and Fe concentrations vary independently, suggesting that they are not controlled by the same redox conditions. Instead, their distribution mainly reflects environmental conditions rather than direct microbial control. In addition, δ⁵⁶Fe values vary between sites (−0.98–0.09‰), providing additional insights into redox conditions during carbonate formation. Together, the data indicate that early diagenetic dolomite formation is governed by site-specific combinations of sulphate reduction, aerobic heterotrophy, EPS-mediated divalent cation binding and fluid pathways, rather than a single mechanism. This study provides a geochemical framework for low-temperature, microbially mediated dolomite formation and identifies which proxies are, and are not, diagnostic of microbial influence in ancient sedimentary records.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148994036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Detrital zircon ages, Lu-Hf isotopes of zircon grains, Sr-Nd isotopes on whole rock and geochemistry of Campanian turbidites in the Eastern Pontides (NE Türkiye): A provenance assessment and Gondwana records","authors":"Çiğdem Saydam Eker,&nbsp;Cem Yücel,&nbsp;Abdullah Kaygusuz,&nbsp;Emre Aydınçakır,&nbsp;Youn-Joong Jeong,&nbsp;Sinan Yılmazer,&nbsp;Kadir Sünnetçi","doi":"10.1002/dep2.70088","DOIUrl":"https://doi.org/10.1002/dep2.70088","url":null,"abstract":"<p>Detrital zircons are crucial stand-ins for the history of continental crust growth and disintegration, as well as the dispersal and assembly of supercontinents. Detrital zircons are effectively used to assess crustal history because sediments transport zircons from source rocks that are no longer at the surface. This study presents detailed Lu-Hf isotopic, U-Pb geochronological analyses of zircon, Sr-Nd isotopic analyses and whole-rock geochemical results from sandstone, volcanically derived sandstone and tuff samples of the Campanian-aged Bozbent Member in the Eastern Pontide Orogen belt of the Sakarya Zone. Sedimentological analyses show that the Bozbent Member was transported and deposited by turbidite currents, while petrographic and geochemical analyses show that the sandstones range from greywacke to litharenite. In this study, U-Pb ages of detrital zircon obtained from Campanian sandstones are presented, along with in situ εHf data. A magmatic origin is indicated by the majority of zircons' oscillatory zoning and by Th/U ratios ranging from 0.2 to 1.5. The ages of detrital zircons range from 2819 to 78 Ma, with most of these zircons being Proterozoic (552–994 Ma). Proterozoic zircons are detrital zircons associated with the Gondwana and the African Craton. The whole-rock geochemical data and Sr-Nd isotope compositions of the sandstones are consistent with local Carboniferous felsic plutons, Jurassic mafic and felsic plutons, Jurassic volcanic rocks, Jurassic clastic rocks and clastic material from Precambrian recycled sediments. It was calculated that more than 90% of the detrital zircons had crystallisation ages older than their depositional ages (CA-DA &gt; 150 Ma, indicative of an extensional basin model). These findings indicate that the Campanian-aged Bozbent Member turbiditic sequence in the Eastern Pontides was deposited in an extensional fore-arc basin and therefore exhibits the petrographic and geochemical characteristics of passive margin sandstones.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70088","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148994035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Sedimentology and geochemistry of the recent sediments of the river system on Hurd Peninsula, Livingston Island, Antarctica","authors":"Yakup Çelik,&nbsp;Merve Özyurt,&nbsp;Raif Kandemir","doi":"10.1002/dep2.70086","DOIUrl":"https://doi.org/10.1002/dep2.70086","url":null,"abstract":"<p>Seasonal ephemeral stream systems on Livingston Island (South Shetland Islands) serve as vital natural laboratories for elucidating sedimentary processes in maritime Antarctic environments. This study presents the first comprehensive petrographic and geochemical records of terrestrial surface sediments in this region to constrain their provenance and sedimentary evolution. Micromorphological analyses reveal that these sediments comprise predominantly poorly to moderately sorted, angular to sub-angular particles ranging from clay to sand, indicative of highly restricted transport. Geochemical proxies, including low Th/U and distinct Zr/Sc and Th/Sc ratios, strongly corroborate a first-cycle sedimentary assemblage with negligible evidence of recycling or hydrodynamic sorting. Although the sediments generally exhibit the low chemical weathering indices typical of cold climates, localised chemical alteration is evidenced by Large Ion Lithophile Element depletion (Cs, Rb, Ba, K) and the presence of kaolinite. This alteration is attributed to the distinctively humid microclimates characteristic of Maritime Antarctica. Furthermore, elemental signatures (Co/Th, Eu/Eu*, La/YbN, Hf, Nd and Y) suggest derivation from a composite mixture of the island's bedrock. Major and trace element geochemistry, coupled with multidimensional discriminant function analyses, demonstrates that the contemporary sediment budget is governed principally by the physical disintegration of Mesozoic–Cenozoic South Shetland magmatic arc rocks—most notably the Miers Bluff Formation and associated intrusive suites. However, the system's polygenetic framework is highlighted by a subtle geochemical shift towards rift-related domains, capturing a subordinate physical influx of Quaternary tephra superimposed onto the foundational arc-crust signature. Ultimately, these integrated geochemical and micromorphological insights provide a critical baseline for decoding source-to-sink sedimentary dynamics in maritime Antarctica, offering a broader window into how high-latitude depositional systems respond to modern polar climate shifts.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Flexural bulges and foredeep basins: Dynamic tectonic control on shifting depocentres and condensed facies, Upper Cretaceous (Santonian), Western Canada Foreland Basin","authors":"Omar N. Al-Mufti,&nbsp;A. Guy Plint,&nbsp;El-Mahadia I. Mohammed,&nbsp;Ireneusz Walaszczyk,&nbsp;Y. Greg Hu","doi":"10.1002/dep2.70087","DOIUrl":"https://doi.org/10.1002/dep2.70087","url":null,"abstract":"<p>Upper Cretaceous (Santonian) shallow-marine mudstone of the Puskwaskau Formation fills the foredeep of the Western Canada Foreland Basin and was deposited on a near-planar, wave-graded ramp. These strata span ~2.3 myr and form an 800-km-long prismatic wedge that, perpendicular to the Rocky Mountain Cordillera, thins from &gt;360 to &lt;40 m over 400 km. The Santonian succession was divided into 12 allomembers, A–L, bounded by marine flooding surfaces. Allomembers A–D, E–H and I–L group into three genetic ‘units’, bounded by subtle disconformities. Isopach maps of the three units, each inferred to span ~760 kyr, show pronounced along-strike variation in thickness. The depocentre of Unit 1 lies between 49 and 53° N, suggesting that a region of active thrust loading lay immediately to the SW. The depocentre of unit 2 is offset 300 km to the NW yet traced 500 km along-strike to the SE, 90 m of mudstone thins to 1 m of bioclast-rich sandstone, which lies atop the forebulge, relatively close to the orogen. Unit 2 also thins 250 km NE (offshore) where the unit comprises 5 m of coccolith- and organic-rich mudstone. Relative to unit 2, the depocentre of unit 3 is offset 300–400 km along-strike to the SE. Isopach maps of individual allomembers, inferred to span ~190 kyr, show that depocentres can migrate laterally up to 300 km between individual allomembers. Mudstone depocentres are interpreted as regions of active flexural subsidence rather than point-sourced accumulations, such as deltas or mud banks. Individual thrust sheets in the Rocky Mountain fold-and-thrust belt may have experienced spatially and temporally discrete episodes of internal thickening and advance; the resulting load produced a corresponding arcuate depocentre in the adjacent foredeep.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70087","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Diagenetic evolution and geochemical controls on carbonate platform development in the Middle Eocene Jahrum Formation, Zagros Basin","authors":"Mehdi Baniasadi,&nbsp;Vahid Ahmadi,&nbsp;Mohammad Reza Esmaeilbeig,&nbsp;Pooria Kianoush","doi":"10.1002/dep2.70089","DOIUrl":"https://doi.org/10.1002/dep2.70089","url":null,"abstract":"<p>The Jahrum Formation constitutes one of the most extensive middle Eocene shallow-marine carbonate successions of the Zagros Basin and preserves an exceptional record of carbonate diagenesis associated with the evolution of the eastern Neo-Tethyan platform. Although previous investigations have documented its lithostratigraphy and larger benthic foraminiferal assemblages, the diagenetic pathways responsible for modifying its primary mineralogical, petrographic and geochemical characteristics remain insufficiently constrained. This study integrates petrographic observations, X-ray diffraction (XRD), cathodoluminescence (CL), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM–EDS), stable carbon and oxygen isotope analyses and pyrite framboid characterisation to reconstruct the diagenetic evolution of the Jahrum Formation in the Lapoie and Kelestan sections of the Zagros Basin. Petrographic observations reveal multiple generations of carbonate cementation, pervasive dolomitisation, recrystallisation of skeletal grains, dissolution and late-stage meteoric alteration. Mineralogical and geochemical analyses demonstrate systematic variations in carbonate mineralogy and isotopic composition associated with successive diagenetic environments. SEM–EDS analyses confirm the occurrence of framboidal pyrite within micritic matrices, whereas pyrite morphology and elemental composition indicate formation under dysoxic to locally anoxic early diagenetic conditions. Stable isotope compositions further suggest progressive modification of primary marine signatures during burial diagenesis and subsequent meteoric fluid interaction. Integration of petrographic, mineralogical and geochemical evidence enables reconstruction of a comprehensive paragenetic sequence linking depositional environments with post-depositional alteration of the carbonate platform. The resulting diagenetic model provides new insights into the evolution of Eocene carbonate systems within the eastern Neo-Tethys and establishes a robust framework for interpreting diagenetic processes affecting shallow-marine carbonate successions throughout the Zagros Basin.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70089","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Microfabric controls on the preservation and erosion of Late Pleistocene freshwater microbialites in northwestern Patagonia, Argentina","authors":"Inès Eymard,&nbsp;María del Pilar Alvarez,&nbsp;Andrés Bilmes,&nbsp;Gabriela Cusminsky,&nbsp;Negar Haghipour,&nbsp;Timothy Eglinton,&nbsp;Crisogono Vasconcelos,&nbsp;Daniel Ariztegui","doi":"10.1002/dep2.70090","DOIUrl":"https://doi.org/10.1002/dep2.70090","url":null,"abstract":"<p>Microbialites are valuable archives of environmental change, but their interpretation is often complicated by differential preservation and post-depositional modification. Fossil Late Pleistocene microbialites preserved along former shorelines of palaeo-Lake Maquinchao (northwestern Patagonia, Argentina) provide an opportunity to investigate the relationships between microbialite fabrics, preservation and erosion in a lacustrine setting. Petrographic observations were combined with cathodoluminescence, μ-XRF mapping, scanning electron microscopy, stable isotope analyses, X-ray diffraction and radiocarbon dating to characterise the internal structure and composition of these fossil microbialites. Two dominant microfabrics were identified: (i) porous micritic shrub fabrics containing filament moulds and microbial-like structures, and (ii) denser laminated spar–micrite fabrics. These fabrics show a systematic spatial distribution within the build-ups, with shrub fabrics occurring preferentially in interior portions and laminated fabrics concentrated along outer and upper surfaces. Mineralogical analyses indicate that both fabrics are composed predominantly of low-Mg calcite, whereas radiocarbon ages constrain carbonate formation between approximately 21 and 14 ka BP. Field observations and microfabric analyses indicate that preservation is strongly influenced by porosity distribution. Dense laminated fabrics form resistant outer layers that enhance preservation, whereas porous shrub fabrics are more susceptible to weathering and erosion. The present morphology of the carbonate build-ups therefore reflects both primary accretionary processes and subsequent differential preservation. These results demonstrate that differential preservation exerts a major control on the morphology and internal architecture of fossil microbialites and highlight the importance of preservation biases when interpreting lacustrine microbial carbonate records.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70090","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Sedimentary facies and stacking patterns of fluvio-deltaic and -estuarine deposits from the Palaeoarchean Moodies Group in the Stolzburg Syncline (Barberton Greenstone Belt, South Africa)","authors":"Sanway Mukhopadhyay,&nbsp;Dennis Schreiber,&nbsp;Nina Wichern,&nbsp;David De Vleeschouwer,&nbsp;Christoph Heubeck,&nbsp;Marcello Gugliotta","doi":"10.1002/dep2.70085","DOIUrl":"https://doi.org/10.1002/dep2.70085","url":null,"abstract":"<p>Investigating fluvio-marine depositional environments from early geological times is of great importance, as they provide key insights into the palaeoenvironmental conditions of the early Earth. The present study aims to reconstruct the deposition and evolution of these systems from the Palaeoarchean Moodies Group in the Stolzburg Syncline of the Barberton Greenstone Belt, South Africa. It is based on a detailed investigation of the new, ~490 m-long research drillcore BASE-5B, using sedimentological logging, facies analysis and palaeocurrent measurements. Thirteen sedimentary facies were recognised and grouped into five facies associations. The stratigraphically lower section of the core, from ~490to ~294 m drilled depth, with an overall coarsening-upward trend, is mainly characterised by unidirectionally cross-stratified sandstones with occasional conglomerates and silicified sulphate concretions; this section was interpreted as a regressive, river-dominated fluvio-deltaic environment. The stratigraphically upper section, from ~294 to ~17 m, with an overall fining-upward trend, is characterised by cross-stratified sandstones with mudstone drapes and bidirectional palaeocurrents; this section was interpreted as a transgressive, fluvio-estuarine environment dominated by combined tidal and riverine processes and with a well-defined turbidity maximum. The vertical stacking pattern implies an evolution from a fluvio-deltaic to a fluvio-estuarine system with an overall regressive to transgressive trend due to an increase in basin subsidence and/or decrease in sediment supply. Two orders of transgressive–regressive cycles are superimposed on this general trend, reflecting relative sea-level fluctuations, most probably driven by changes in sediment supply. These results help in understanding the sedimentary dynamics of Archean fluvial-marine systems and their response to external forcings.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70085","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Confinement-controlled architecture of stacked resedimented volcaniclastic beds in the Miocene Eoil Basin, SE Korea","authors":"Chang Woo Kwon","doi":"10.1002/dep2.70083","DOIUrl":"https://doi.org/10.1002/dep2.70083","url":null,"abstract":"<p>Volcano-sedimentary basins record complex interactions among volcaniclastic sediment input, accommodation creation and pre-depositional relief, yet outcrop-scale constraints on how topographic confinement controls resedimented volcaniclastic architecture remain limited. In the Miocene syn-rift Eoil Basin, SE Korea, metre-thick volcaniclastic beds interbedded with lacustrine-to-swamp deposits are exposed along a <i>ca</i> 100 m roadcut. Seven measured Sections were correlated to document lithofacies architecture and its relationship to evolving syndepositional topography. Units II–VI comprise stacked subunits produced by successive debris flow pulses and related flow transformations, expressed by recurrent transitions from massive, poorly sorted conglomerate (GSm) to normally graded conglomerate to sandstone (GSn) and/or crudely stratified gravelly sandstone to sandstone (Ss). These successions record composite sediment gravity flows in which concentrated debris flow divisions passed into more dilute hyperconcentrated-flow and tractionally modified trailing divisions during runout. Unit III provides the strongest evidence for a probable multi-surge event, based on lateral splitting and amalgamation of compositionally similar subunits within common boundaries and the absence of persistent repose deposits. In Units II and IV–VI, the available evidence does not uniquely distinguish intra-event surges from separate events occurring in close succession; these units are therefore described as deposits of successive flow pulses. Unit II records deposition within a localised topographic low, Unit III shows pronounced cross-channel facies partitioning and Units IV–VI record compensational stacking across progressively lower-relief surfaces. Pumice-rich Units II, IV and V reflect selective remobilisation with limited incorporation of intrabasinal material, whereas mixed pumice–scoria–lithic Units III and VI record either local channelised entrainment or upstream integration of multiple sediment stores. These results demonstrate that topographic confinement and sediment-routing pathways jointly control facies architecture and compositional variability in volcano-sedimentary basin fills.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70083","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}