Depositional Record最新文献

{"title":"Tidal versus fluvial point bars: Key features from the integration of outcrop, core and wireline log information of Triassic examples","authors":"Luis Miguel Yeste,&nbsp;Marc Gil-Ortiz,&nbsp;Fernando García-García,&nbsp;César Viseras,&nbsp;Neil David Mcdougall,&nbsp;Patricia Cabello,&nbsp;Luca Caracciolo","doi":"10.1002/dep2.282","DOIUrl":"10.1002/dep2.282","url":null,"abstract":"<p>The Triassic red beds of the Tabular Cover of the Iberian Meseta are an excellent reservoir outcrop analogue, a direct consequence of high-quality exposures, which offer exceptional three-dimensional outcrops, as well as a wide variability of depositional environments. Fluvial and transitional with tide-influenced and wave-influenced settings are recognised. Three point bar geobodies of similar scale, but influenced by different processes, were selected from this succession. Point bar geobody 1 was influenced by purely fluvial processes while geobodies 2 and 3 were tide-influenced. Both types of geobody were developed as point bar deposits in sinuous channels. A fully integrated study was carried out on these geobodies, utilising both outcrop and subsurface-based approaches, to characterise the key differences between fluvial and tidal point bars in the sedimentary record. The outcrop-based component involved traditional field data collection methods alongside digital techniques and data capture, including the use of digital outcrop models. Additionally, subsurface-based methods were employed, utilising core and wireline logs obtained from wells drilled in close proximity to the outcrop. The integration of these approaches aims to accurately differentiate the depositional settings of the three different geobodies, which while apparently very similar in many key respects also exhibit considerable differences when considered from the perspective of subsurface management of potentially similar geobodies. This study also emphasises the need to clearly distinguish high-sinuosity deposits based on their depositional sub-environment in order to properly evaluate their potential for subsurface management. Additionally, it highlights the presence and importance of internal baffles that may well influence fluid migration and indeed even compartmentalise geobodies. Three point bar geobodies of similar scale, but influenced by different processes, have been selected in this succession. A fully integrated study was carried out on these geobodies, utilising both outcrop-based and subsurface-based approaches, to characterise the key differences between fluvial and tidal point bars in the sedimentary record.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"793-820"},"PeriodicalIF":1.9,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.282","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140981331","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":"Advances in Limnogeology: The lake-basin-type model revisited 25 years after…anomalies, conundrums and upgrades","authors":"Cecilia A. Benavente,&nbsp;Kevin M. Bohacs","doi":"10.1002/dep2.280","DOIUrl":"https://doi.org/10.1002/dep2.280","url":null,"abstract":"<p>The lake-basin-type model classified the stratigraphic record of ancient lake systems according to rates of potential accommodation relative to sediment + water supply. The model convolved all modes and paths of water supply (direct fall, surficial, subsurface) with amounts and types of sediment supply (clastic, biogenic, chemical) into a single basin-filling volume term (sediment + water); its major strength was its widespread applicability. This was supported by subsequent investigations confirming the utility of this approach, but it also revealed some important limitations due to simplifications in the original model. The model has been expanded here to address all inland waters (lakes, ponds, wetlands, playas) as well as adding two major subdivisions of the sediment + water term: (1) water supply paths and (2) the volume of water supply relative to sediment supply. Water supply flow paths in the subsurface are subdivided into ‘throughflow’, ‘recharge’ and ‘discharge’. Each of these groundwater hydrology states can be defined quite precisely by the ratio of net outflow to inflow, from persistently open to consistently closed. These paths can be deciphered using stable carbonate and oxygen isotope composition of primary lacustrine limestones, detailed sedimentology, stratigraphy, palaeontology and mineralogy. Distinguishing water supply paths provides additional insights into playa systems and the occurrence and character of evaporites and carbonates. The volume ratio of water to sediment supply most directly influences the water depths of lakes, ponds and wetlands, which affect water body hydrodynamics and ecosystem behaviour as well as the details of stratal stacking and depositional sequences. It helps fine-tune estimates of the distribution of sediment texture, bedding, composition and organic matter content. The aim of this contribution is to address questions about the fundamental types of inland water bodies and to explain the new lake-basin subtypes and provide examples that illustrate their potential to enable higher-resolution, robust analysis of inland water systems and their stratigraphic records.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"748-792"},"PeriodicalIF":1.9,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.280","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142692036","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":"A tale of two end members: Tidal deposits in a semi-arid, low subsidence, open coastal setting versus a high runoff, high subsidence, restricted environment","authors":"Anton F.-J. Wroblewski,&nbsp;Ronald J. Steel,&nbsp;Emma A. Morris,&nbsp;Jon Schueth","doi":"10.1002/dep2.284","DOIUrl":"10.1002/dep2.284","url":null,"abstract":"<p>Jurassic and Palaeocene tidal deposits of the epeiric Western Interior Sea in Wyoming, USA, differ significantly due to their contrasting climates and tectonic, geographic and depositional settings. Tidally generated, cross-bedded sandstone bodies contained by incisions are common to both settings and can potentially be uncritically attributed to marine flooding of fluvial systems. Key differences in lithology, ichnology and relationships with surrounding sediment reveal fundamentally different depositional settings, however. The Jurassic system occupied a low accommodation, semi-arid environment, with geographically open shorelines as relative sea-level fell, creating an unconformable contact with the underlying, storm wave-dominated shelf and shoreface deposits. Siliciclastic, intertidal flats formed adjacent to coastal aeolian and fluvial environments during brief turnarounds from the degradational (forced regressive) to aggradational and retrogradational (transgressive) system tract. Basinward of these environments, metre to decimetre-scale cross-bedded, bioclastic, subtidal compound dunes and tidal inlet complexes accumulated in areas of minimal clastic flux and within incisions created by submarine tidal currents. By contrast, the Palaeocene tidal systems formed in a high accommodation, subtropical setting, as rising sea levels forced the fluvial to marine transition zone landward and flooded coastal swamps, forming geographically irregular, back-barrier complexes and tidally influenced fluvial systems. High volumes of siliciclastics, terrigenous organic material and freshwater were delivered by the rivers and created physicochemical stress on the marine embayments. Sandy tidal flat deposits accumulated in lagoons and interdistributary bays, but unlike the Jurassic examples, they do not mark a turnaround from the falling stage to the transgressive system tract. The potential preservation window for tidalites is significantly greater vertically in the aggradational to retrogradational setting than in the degradational system due to greater accommodation. The preservation window is vertically smaller, but areally greater in the Jurassic, forced regressive system because of basinward enhancement of tidal currents driven by complex palaeobathymetry caused by tectonic activity of local pre-Laramide uplifts.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"720-747"},"PeriodicalIF":1.9,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.284","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140674748","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":"Incorporation of substrate blocks into mass transport deposits: Insights from subsurface and outcrop studies","authors":"Victoria Valdez Buso,&nbsp;Ben Kneller,&nbsp;Vanessa da Silva Reis Assis,&nbsp;Fernando Farias Vesely,&nbsp;Juan Pablo Milana","doi":"10.1002/dep2.283","DOIUrl":"10.1002/dep2.283","url":null,"abstract":"<p>Mass movements are common on the continental slope, affecting not only the subsequent sea floor morphology but often substantially modifying the underlying deposits. Various styles of substrate interaction have been recognised, representing the various degrees of involvement of the underlying material and its incorporation into the mass movement. This work presents a new style of basal interaction not previously described. Based on the morphology of the basal surface of a mass transport deposit, this can be recognised both in seismic data and in an outcrop analogue. A subsurface example, from an <i>ca</i> 100 m thick mass transport deposit located in Santos Basin, offshore Brazil, displays a basal surface with spoon-shaped scours or scoops. These scoops are of the order of tens up to 400 m in maximum dimension, where masses of underlying sediment have been removed and incorporated into the mass movement. Outcrops used for this work are located in La Rioja Province, Western Argentina, where the study involves a well-exposed <i>ca</i> 200 m thick mass transport deposit that crops out continuously over 7 km. Its basal surface is incised irregularly into the underlying sandstones, incorporating the blocks of sandstone into the mass movement. The striking similarities observed between outcrop examples and the northern Santos Basin suggest that they can be effective analogues, facilitating a comprehensive understanding of mass transport deposit dynamics across diverse basin environments.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"708-719"},"PeriodicalIF":1.9,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.283","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140691540","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":"Provenance and the U–Pb age constraints on the tuff beds of the Late Jurassic–Early Cretaceous Bazhenovo Formation, West Siberian Basin","authors":"Timur Bulatov,&nbsp;Yakov Yermakov,&nbsp;Anna Kulikova,&nbsp;Bulat Gareev,&nbsp;Mikhail Spasennykh","doi":"10.1002/dep2.281","DOIUrl":"10.1002/dep2.281","url":null,"abstract":"<p>Thin tuff beds of the Late Jurassic–Early Cretaceous Bazhenovo Formation are laterally widespread in the central part of the West Siberian Basin (<i>ca</i> 0.5 million km²). However, the source of the tuff beds remains unclear. The stratigraphy, geochemistry and geochronology of the tuff beds were investigated to reveal their magmatic origin and potential source region. Most of the tuff beds are recorded in member 4 and can be correlated through the Bazhenovo sequence. Thin-section petrography and X-ray diffraction indicate that the tuffs mostly comprise clay minerals and K-feldspars. Less common minerals are plagioclase, quartz and pyrite. The geochemical composition of the Bazhenovo tuff beds suggests a parental magma origin of andesite/basalt, which came from volcanic arc-related settings. Considering the results of geochemical studies along with LA-ICP-MS zircon U–Pb dating (141.3 ± 0.3/2.8 Ma), the palaeovolcanoes of the Caucasus region or south-east Mongolia–North-East China are one of the potential source regions of the tuffs. The record of these tuffs indicates the intensive volcanic eruption during the Volgian–Ryazanian, accompanied by a very low-sedimentation rate and preservation in a reducing environment. The tuff beds have broad implications as an isochronous marker horizon and constraints for the numerical age of the Jurassic–Cretaceous boundary in the Boreal Realm.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 2","pages":"312-334"},"PeriodicalIF":2.4,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.281","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140723109","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":"The depositional record of the French Flemish Coastal plain since antiquity: Impacts of land reclamation in a tide-dominated estuary","authors":"Rachid Ouchaou,&nbsp;Jean-Yves Reynaud,&nbsp;Youn Besse,&nbsp;Anissa Tilehghouatine,&nbsp;Eric Armynot du Châtelet,&nbsp;Alain Trentesaux,&nbsp;Romain Abraham,&nbsp;Laurent Deschodt,&nbsp;Guillaume Hulin,&nbsp;Samuel Desoutter,&nbsp;Benjamin Fores,&nbsp;François-Xavier Simon,&nbsp;Mathieu Lançon","doi":"10.1002/dep2.279","DOIUrl":"10.1002/dep2.279","url":null,"abstract":"<p>The French Flemish Coastal Plain, which extends from Denmark to France, is characterised by a topography close to sea level and protected by a system of coastal dunes. Quaternary sediments, comprised of marine, estuarine and continental deposits, accumulated by infilling and then prograding above a network of incised valleys. This study focusses on the Holocene infill of the Denna palaeoestuary, south-west to Dunkerque. Surface geophysics (electrical conductivity and ground-penetrating radar) and vibrocore data are used to reconstruct the landscape evolution during the last stages of sedimentation. The conductivity map highlights the last network of tidal channels, ditches and dikes of the eastern side of the palaeoestuary. Over the upper 4 m of the infill, the ground-penetrating radar profiles show two superimposed units. The bottom unit is composed of meandering channel bars and the top unit of flat strata intersected by sparse channels, mostly infilled in place. The sediment analysis of the vibrocores shows a predominantly sandy filling of marine to estuarine origin, evidenced by sponge spicules and a fauna of bivalves and foraminifera adapted to brackish settings. The uppermost deposit exhibits an oxidation profile which marks the groundwater zone transition. Clayey sediments are also present, infilling the uppermost channels and ditches dug during reclamation, in increasing proportions towards the axis of the estuarine palaeovalley. The tidal signature of sedimentary dynamics is evidenced by heterolithic facies in some channel fills and tidal rhythmites infilling scour depressions linked to dike breaching. The abrupt decrease in channel dynamics across the unit boundary, although sedimentation remained sandy in the upper unit, coincides with the development of embankment of the estuarine border and is tentatively interpreted as a result of reclamation.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"685-707"},"PeriodicalIF":1.9,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.279","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140384651","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":"New palaeocurrent analysis approach from two-dimensional trough cross-strata using photographs and anisotropy of magnetic susceptibility","authors":"Jasper Maars,&nbsp;Gijs van Dijk,&nbsp;Mark J. Dekkers,&nbsp;F. Javier Hernández-Molina,&nbsp;Federico Andreetto,&nbsp;Francisco J. Rodríguez-Tovar,&nbsp;Wout Krijgsman","doi":"10.1002/dep2.277","DOIUrl":"10.1002/dep2.277","url":null,"abstract":"<p>Palaeocurrent analysis is vital for basin analysis and helps in the interpretation of depositional environments (along-slope or downslope). For that, it is crucial to have multiple measuring methods at hand to apply palaeocurrent analysis with a wide range of different datasets (outcrops, cores and photographs). Here, two relatively underexploited palaeocurrent measurement techniques are assessed when applied to trough cross-stratification observed in the Arenazzolo Formation at Eraclea Minoa (Sicily). The first technique is a novel design of a qualitative approach to infer palaeocurrent directions from photographs of two-dimensional sedimentary structures. The second technique involves measurements of the anisotropy of magnetic susceptibility from drilled samples. A broad agreement, with overlapping uncertainty boundaries, is observed between results from both techniques. This agreement validates the use of trough cross-strata to infer palaeocurrent directions. Moreover, the addition of photographs improves reproducibility and prevents a bias towards the best-exposed troughs. The application of both techniques to outcrops and sedimentary cores provides new opportunities for palaeocurrent analysis in any type of sedimentary environment.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 2","pages":"298-311"},"PeriodicalIF":2.4,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.277","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140214292","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":"Hydrologic remobilisation of tephra-fall deposits: A sedimentological analysis throughout fluvio-lacustrine systems of North-West Patagonia","authors":"Nahuel Losano,&nbsp;Gustavo Villarosa,&nbsp;Débora Beigt,&nbsp;Pablo Amat,&nbsp;Julieta Cottet,&nbsp;Valeria Outes","doi":"10.1002/dep2.274","DOIUrl":"10.1002/dep2.274","url":null,"abstract":"<p>This paper explores the response to Holocene ash inundation in different sub-environments of two fluvio-lacustrine systems, Las Piedritas and Totoral, focussing on the processes of volcaniclastic remobilisation. Sediment cores and outcrops were used to recognise three deposit types, noting how some differ from lahars, through sedimentological and stratigraphic analysis: (1) thick, laterally discontinuous, pumice-dominated deposits occur overlying alluvial plain and lower terrace surfaces across both watersheds; (2) chaotic, extremely poorly sorted and matrix-supported beds composed of both epiclastic and pyroclastic material occur as two conspicuous deposits at Las Piedritas outcrops, in a low-gradient confined channel setting; and (3) layers with an exclusively pyroclastic composition and no flow sedimentary structures or fragment roundness were found draping each of the two chaotic intervals and intercalating with the background sediment in Las Piedritas prodelta. Thick pumice packages capping the floodplains resulted from the overflow of streams carrying a floating pumice load. Due to its positive buoyancy, the pumice is transported as a slowly moving overlying mantle without mixing with the streamflow. The disorganised pattern and poor sorting of the matrix-rich polymictic beds are consistent with laminar, gravity-driven, high-concentration flows. They constitute secondary lahars, originating upstream from large run-off processes that reworked a pyroclastic substrate. The lack of reworking features in the vitric-rich units identified in the lake core retrieved from Las Piedritas prodelta, as well as the continuous and widespread occurrences of those interbedded in upstream outcrops, indicate an airfall origin. No reworked tephra unit is recognised in the prodelta sediment record, although various deposits from the hydrologic remobilisation of airfall tephra are found along the subaerial portion of both watersheds. Apparently, large amounts of flotation-remobilised tephra were retained on the delta plain, while another considerable fraction would have been carried away from the creek mouth under the influence of dominant regional winds.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"670-684"},"PeriodicalIF":1.9,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.274","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140237576","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":"Geochemical and microbiological variability of aerobic and anaerobic sediments along a bifurcated sulphate-saturated brine spring in western Canada","authors":"Paul L. Broughton","doi":"10.1002/dep2.276","DOIUrl":"10.1002/dep2.276","url":null,"abstract":"<p>A tufa mound developed at La Saline Lake, an oxbow of the Athabasca River in the Athabasca Oil Sands deposit of north-east Alberta, is characterised by an unusual emplacement of a gypsum caprock. This two-tiered architecture resulted from the bicarbonate-saturated groundwater flow along Upper Devonian limestone being redirected deeper and encountering the halite–anhydrite dissolution trend within the underlying Middle Devonian Prairie Evaporite Formation, 175 to 200 m below. Migrations up-section of sulphate-saturated brine resulted in the gypsum caprock on the tufa mound and discharge of a sulphate-saturated brine spring with total dissolved solids of <i>ca</i> 80,000 mg/L. The brine spring is bifurcated with flows to the south-west and north-west. Calcite–gypsum thrombolytic bottom sediments along the south-western branch were covered by a halite deposit and subsequently a gypsum crust with a microbial community dominated by the cyanobacteria <i>Coleofasciculus chthonoplastes</i>. The thrombolite contact zone with the halite–gypsum encrustation has a more diversified community with the cyanobacteria <i>Dactylococcopsis</i>. Cyanobacterial mats that wrap around the bulbous gypsum crust protuberances distributed along the brine pool bottom surfaces have significant eukaryotic diversity, represented by the heterotrophic Ochrophyte <i>Paraphysomonas</i>. In contrast, sediments accumulated along the adjacent spring branch flow to the north-west were thicker and clogged by abundant decomposed and fermented floral debris, unlike the deposit accumulated along the south-western branch. This resulted in an oxygen-depleted anaerobic environment dominated by sulphate-reducing bacteria resulting in a calcite-rich and sulphate-starved anaerobic sediment with <i>ca</i> 20% elemental sulphur and emanation of H₂S gas.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"637-669"},"PeriodicalIF":1.9,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.276","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140265323","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":"Water discharge and sediment flux intermittency in the fluvial Escanilla Formation, Spain: Implications for changes in stratigraphic architecture","authors":"Nikhil Sharma,&nbsp;Alexander C. Whittaker,&nbsp;Thierry Adatte,&nbsp;Sébastien Castelltort","doi":"10.1002/dep2.272","DOIUrl":"https://doi.org/10.1002/dep2.272","url":null,"abstract":"<p>Water discharge and sediment flux variations are important parameters controlling the morphodynamic behaviour of rivers. Although quantitative estimates for water discharge and sediment flux variability are well-constrained for modern rivers, far fewer assessments of flow and sediment flux intermittency in ancient fluvial systems from the rock record are available. In this study, a relationship between water discharge, sediment flux variability and patterns of changing fluvial stratigraphic architecture in the Middle Eocene Escanilla Formation, Spain, is explored. Water discharge intermittency factor (I_WF), calculated as a ratio of the total water discharge (over the averaging time period) to the instantaneous channel-forming water discharge if sustained for the same period, ranges from 0.03 to 0.11 in the high amalgamation intervals and from 0.10 to 0.32 in the low amalgamation intervals. Similarly, the sediment flux intermittency factor (I_SF) is estimated to be in the range of 0.008 to 0.01 in the high amalgamation intervals and of 0.01 to 0.03 in the low amalgamation intervals. Consequently, high amalgamation intervals were most probably deposited under more intermittent and short-lived intense precipitation events while low amalgamation intervals were the result of less intermittent flows spread throughout the year. Overall, these estimates are consistent with values from modern ephemeral rivers typically found in arid to semi-arid climate and is in agreement with available proxy data for the Middle Eocene climatic context of the studied alluvial system. This highlights an important connection between hydroclimate, river morphodynamics and landscape evolution, and has implications to predict river flow and sediment transport across the Earth's surface in the geological past.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 1","pages":"245-259"},"PeriodicalIF":2.4,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.272","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139976552","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}