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Rosales-Hoz, L., A. Carranza-Edwards, C. Mendez-Jaime, and M. A. Monreal-Gómez. "Metals in shelf sediments and their association with continental discharges in a tropical zone." Marine and Freshwater Research 50, no. 3 (1999): 189. http://dx.doi.org/10.1071/mf98107.
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Geochemical studies of shelf sediments of the south-eastern Gulf of Mexico were carried out to understand the influence of fluvial and fluvio–lagoonal discharges on sediment geochemistry and to study elemental distribution patterns that could be used together with hydrographic and sedimentological data to assess depth circulation. On the basis of sediment chemical composition, three provinces were identified: fluvial, fluvio–lagoonal and calcareous; their distribution is a function of circulation patterns and fluvio and fluvio–lagoonal discharges. Factor analysis separated the sediments into three groups: fluvial influence, anthropic activities and fluvio–lagoonal origin.
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Woronko, Barbara, Paweł Zieliński, and Robert Jan Sokołowski. "Climate evolution during the Pleniglacial and Late Glacial as recorded in quartz grain morphoscopy of fluvial to aeolian successions of the European Sand Belt." Geologos 21, no. 2 (2015): 89–103. http://dx.doi.org/10.1515/logos-2015-0005.
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Abstract We present results of research into fluvial to aeolian successions at four sites in the foreland of the Last Glacial Maximum, i.e., the central part of the “European Sand Belt”. These sites include dune fields on higher-lying river terraces and alluvial fans. Sediments were subjected to detailed lithofacies analyses and sampling for morphoscopic assessment of quartz grains. Based on these results, three units were identified in the sedimentary succession: fluvial, fluvio-aeolian and aeolian. Material with traces of aeolian origin predominate in these sediments and this enabled conclusions on the activity of aeolian processes during the Pleniglacial and Late Glacial, and the source of sediment supply to be drawn. Aeolian processes played a major role in the deposition of the lower portions of the fluvial and fluvio-aeolian units. Aeolian material in the fluvial unit stems from aeolian accumulation of fluvial sediments within the valley as well as particles transported by wind from beyond the valley. The fluvio-aeolian unit is composed mainly of fluvial sediments that were subject to multiple redeposition, and long-term, intensive processing in an aeolian environment. In spite of the asynchronous onset of deposition of the fluvio-aeolian unit, it is characterised by the greatest homogeneity of structural and textural characteristics. Although the aeolian unit was laid down simultaneously, it is typified by the widest range of variation in quartz morphoscopic traits. It reflects local factors, mainly the origin of the source material, rather than climate. The duration of dune-formation processes was too short to be reflected in the morphoscopy of quartz grains.
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Marinho, Rogério Ribeiro, Antonio Fábio Sabbá Guimarães Vieira, and Feliciano De Souza Maciel. "Análise Montante-Jusante da Granulometria dos Sedimentos de Fundo e Suspenso do Rio Negro e Tributários (Bacia Amazônica, Brasil)." Revista Brasileira de Geografia Física 14, no. 2 (2021): 997. http://dx.doi.org/10.26848/rbgf.v14.2.p997-1008.
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O conhecimento das características físicas de sedimentos transportados por grandes sistemas fluviais possui significativa importância para o entendimento de processos geomorfológicos e hidrológicos. O nível de conhecimento dos grandes sistemas fluviais da Amazônia e sua relação com o transporte de sedimentos ainda é limitado, resultando em lacunas de conhecimento sobre a dinâmica da paisagem nesta complexa região. Este trabalho teve como objetivo avaliar a distribuição espacial da granulometria de sedimentos de fundo e suspenso do Rio Negro e tributários. Realizou-se análise da distribuição do tamanho dos sedimentos em seções amostrais localizadas no alto, médio e baixo curso do Rio Negro. Os resultados da análise granulométrica da carga de fundo indicam a predominância de sedimentos com tamanho variando de 0,25 a 1,0 mm (principalmente areia fina, areia média e areia grossa) enquanto no baixo curso as amostram oscilaram de areia fina a partículas lamosas (< 0,50 mm). No Rio Negro os sedimentos suspensos são compostos principalmente de partículas finas de silte (90% menor que 80 µm) com diâmetro mediano (D50) de 25 µm. As características granulométricas apresentadas neste trabalho fornecem subsídios para o entendimento de processos hidrodinâmicos de transporte e deposição dos sedimentos de fundo e suspenso neste gigante sistema fluvial. Upstream-downstream Granulometry Analysis of bed and suspended sediments in the Negro River Basin (Amazon Basin, Brazil)A B S T R A C TThe knowledge of the physical characteristics of sediments transported by large river systems has significant importance for the understanding of geomorphological and hydrological processes. The level of knowledge of the large rivers of the Amazon basin and their relationship with sediment transport is limited, resulting in gaps about the dynamics of the landscape in this complex region. This article analyzes the spatial distribution of granulometry of bed and suspended sediments in the Negro River and tributaries. An analysis of the sediment size distribution was carried out in sample sections located in the upper, middle and lower reaches of the Negro River. The results of the granulometric analysis of the bed load indicate the predominance of sediments with sizes ranging from 0.25 to 1.0 mm (mainly fine sand, medium sand and coarse sand) while in the low course they showed oscillated from fine sand to muddy particles (<0.50 mm). In the Negro River basin the suspended sediments are composed mainly of fine silt particles (90% less than 80 µm) with a median diameter (D50) of 25 µm. The granulometric characteristics presented in this work provide subsidies for the understanding of hydrodynamic processes of transport and deposition of bed and suspended sediments in this huge fluvial system.Keywords: sediment transport, Amazon floodplain, multichannel river, anabranching
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Sawakuchi, André Oliveira, Vinicius Ribau Mendes, Fabiano do Nascimento Pupim, et al. "Optically stimulated luminescence and isothermal thermoluminescence dating of high sensitivity and well bleached quartz from Brazilian sediments: from Late Holocene to beyond the Quaternary?" Brazilian Journal of Geology 46, suppl 1 (2016): 209–26. http://dx.doi.org/10.1590/2317-488920160030295.
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ABSTRACT: The development of optically stimulated luminescence (OSL) dating of sediments has led to considerable advance in the geochronology of the Quaternary. OSL dating is a well established technique to determine sediment burial ages from tens of years to few hundred thousand years. Recent studies have shown that Quaternary sediments of Brazil are dominated by quartz grains with high luminescence sensitivity, allowing the determination of precise and reliable OSL burial ages. In this paper, we show examples of OSL dating of quartz aliquots and single grains from different regions in Brazil, including young coastal-eolian Late Holocene (< 100 years) to Late Pleistocene (~ 150 ka) fluvial sediments. We discuss the OSL data and ages of sediments from carbonate and terrigenous (distributary and tributary systems) fluvial depositional contexts in Brazil. Most of the studied fluvial sediments show equivalent dose distributions with low to moderate dispersion, suggesting well bleached sediments. The comparison between aliquot and single grain data suggests that high overdispersion in equivalent dose distributions of some samples is more related with sediment mixture due to bioturbation than with incomplete bleaching during transport. Well bleached fluvial sediments contrast with the poor bleached pattern usually described for fluvial sediments in the literature. A large part of the fluvial sedimentary record in Brazil is older than the age limit for quartz OSL dating using blue light stimulation. Thus, isothermal thermoluminescence (ITL) dating protocols were tested for dating of fluvial sands from the Xingu River (eastern Amazonia). The studied sample can recover reliable equivalent doses up to 1600 Gy using the ITL 310oC signal. Therefore, this signal would be suitable to extend the age limit of quartz luminescence to the whole Quaternary or beyond (> 2 Ma) in the low dose rate (0.5 - 1.0 Gy/ka) environments typical for Brazilian sediments.
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Wang, H., and X. Jia. "Selective deposition response to aeolian-fluvial sediment supply in the desert braided channel of the Upper Yellow River, China." Natural Hazards and Earth System Sciences Discussions 3, no. 2 (2015): 1269–90. http://dx.doi.org/10.5194/nhessd-3-1269-2015.
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Abstract. Rivers flow across aeolian dunes and develop braided stream channels. Both aeolian and fluvial sediment supplies regulate sediment transport and deposition in such a cross-dune braided river. Here we show a significant selective deposition in response to both aeolian and fluvial sediment supplies in the Ulan Buh desert braided channel. This selective deposition developed by the interaction between the flows and the Aeolian-fluvial sediment supplies, making the coarser sediments (> 0.08 mm) from aeolian sand supply and bank erosion to accumulate in the channel center and the finer fluvial sediments (< 0.08 mm) to be deposited on the bar and floodplain surfaces and forming a coarser-grained thalweg bed bounded by finer-grained floodplain surfaces. This lateral selective deposition reduces the downstream sediment transport and is a primary reason for the formation of "above-ground river" in the braided reach of the Upper Yellow River in response to aeolian and fluvial sediment supplies.
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Wang, H., X. Jia, Y. Li, and W. Peng. "Selective deposition response to aeolian–fluvial sediment supply in the desert braided channel of the upper Yellow River, China." Natural Hazards and Earth System Sciences 15, no. 9 (2015): 1955–62. http://dx.doi.org/10.5194/nhess-15-1955-2015.
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Abstract. Rivers flow across aeolian dunes and develop braided stream channels. Both aeolian and fluvial sediment supplies regulate sediment transport and deposition in such cross-dune braided rivers. Here we show a significant selective deposition in response to both aeolian and fluvial sediment supplies in the Ulan Buh desert braided channel. The Ulan Buh desert is the main coarse sediment source for this desert braided channel, and the mean percentage of the coarser (> 0.08 mm) grains on the aeolian dunes surface is 95.34 %. The lateral selective deposition process is developed by the interaction between the flows and the aeolian–fluvial sediment supplies, causing the coarser sediments (> 0.08 mm) from aeolian sand supply and bank erosion to accumulate in the channel centre and the finer fluvial sediments (< 0.08 mm) to be deposited on the bar and floodplain surfaces, forming a coarser-grained thalweg bed bounded by finer-grained floodplain surfaces. This lateral selective deposition reduces the downstream sediment transport and is a primary reason for the formation of an "above-ground" river in the braided reach of the upper Yellow River in response to aeolian and fluvial sediment supplies.
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Słowik-Opoka, Ewa, and Anna Michno. "Factors Diversifying the Characteristics of Fluvial Sediments Accumulated in Mountain Stream Channels—A Case Study from the Polish Carpathians." Water 16, no. 23 (2024): 3476. https://doi.org/10.3390/w16233476.
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This paper presents the diversification of fluvial sediments caused by the occurrence of coarse woody debris (CWD), boulder steps (BSs), and mixed structures (MSs), understood as a combination of CWD and BSs in a stream channel in a small forested catchment in the Polish Carpathians. This research is crucial for understanding the role of this kind of threshold present in a stream channel in shaping fluvial sediment characteristics in small forested mountain catchments. Our hypothesis is that the threshold type in a stream channel determines fluvial sediment diversification. This was verified in field research, including identification of the channel’s morphodynamic structure and the morphometric characteristics of CWD, BSs, and MSs as well as the collection of fluvial sediments upstream and downstream of them. In order to preserve research objectivity, tests were performed during comparable flow conditions in the summer (EX1) and autumn (EX2) periods. The statistical analysis showed that the type of threshold significantly affects the processing, size, and shape diversification of mineral material. This diversity is particularly noticeable in fluvial sediments within CWD and MSs, which retain material of more diverse sizes and shapes.
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Halifa-Marín, A., P. Pérez-Cutillas, M. Almagro, and C. Boix-Fayos. "Presión antrópica sobre cuencas de drenaje en ecosistemas frágiles: variaciones en las existencias (stock) de carbono orgánico asociadas a cambios morfológicos fluviales." Cuadernos de Investigación Geográfica 45, no. 1 (2019): 245. http://dx.doi.org/10.18172/cig.3690.
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Anthropic changes in the drainage area of catchments can influence dominant erosion processes and sediment sources and mobilize specific carbon pools. It also causes changes in the sedimentary dynamics and thus in the fluvial morphology. At the same time fluvial morphologies can create the conditions for stabilizing organic carbon (OC) in sediments by burial, carbon preservation, slowing down mineralization processes, and terrestrial or aquatic plant colonization. All this might have a significant impact on the fluvial carbon sink or sources. This work explores the impact of changes in the drainage area (reforestation, check-dam building, agricultural abandonment) on fluvial morphology and on the sedimentary carbon sink of an arid and erodible catchment. The methodological approach combines cartographic analysis of land use, geomorphological photointerpretation of the channel and slope-channel connections in 1956 and 2016. Furthermore, soil and sediment sampling across the catchment for organic carbon stock determination was carried out. The watershed underwent a drastic transformation of land use from 1956, changing from an agrarian scenario to a forest pattern in 2016. This evolution altered sedimentological dynamics and fluvial morphologies. The active channel was narrowed (52%) whereas bank erosion (77%) and the adjacent gullies (11%) increased. The inner alluvial plain increased up to 31% and alluvial fans up to 37%. In addition, vegetation in the channel increased up to 16%. All this led to an increase of the total OC pool of fluvial sediments (12%), slightly above than the increase of OC total pool in the soils of the catchment (10%). The ratio of the OC stock sediments/soils was > 0.8, which indicates the large capacity of carbon sequestration of fluvial sediments, with OC stocks larger than those of agricultural soils. It was found that the geomorphological dynamics plays an important role in the OC fluvial flows. In scenarios of channel narrowing and vegetation encroachment of fluvial morphologies, the sediments can stabilize and generate OC sinks. These processes of OC sequestration in dry and ephemeral channels can have a large relevance for various ecosystem services and should be considered in the management of fluvial sedimentary areas.
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Galia, Tomáš, and Václav Škarpich. "Coarse Bed Sediments in a Headwater Channel as Indicators of Fluvial Processes and Slope-Channel Coupling: A Case Study from the Carpathian Mountains (Czech Republic)." Moravian Geographical Reports 21, no. 3 (2013): 2–11. http://dx.doi.org/10.2478/mgr-2013-0012.
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Abstract The character of riverbed sediments usually reflects fluvial processes and the dynamics of sediment transport in fluvial systems. The approach in this study was based on the measurement of the largest boulders located within a bankfull channel, and on the observation of changes in their size in the longitudinal profile of a headwater stream in the Moravian-Silesian Beskids Mountains. The resulting trends in a particle-size index reflect the character of sediment delivery into channel segments and the recent channel-forming processes. The largest boulders were observed in channel sections with a strong interaction of slope and fluvial processes, and a slight coarsening of sediments was recorded in the incised downstream sections of the longitudinal stream profile. In contrast, the refining of bed sediments was typical of the transitional zone between slope-channel coupled reaches and an alluvial cone characterised by a tendency to material aggradation.
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Aleixo, Yan De Mello, Márcio Henrique De Campos Zancopé, and Luis Felipe Soares Cherem. "O Papel do Perfil Longitudinal na atenuação do Potencial de Transporte de Sedimentos em Bacias Hidrográficas: o caso do Parque Estadual de Terra Ronca (GO), Brasil." Revista Brasileira de Geografia Física 12, no. 5 (2019): 1730. http://dx.doi.org/10.26848/rbgf.v12.5.p1730-1745.
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A forma dos perfis longitudinais dos cursos d’água associada à distribuição das planícies aluviais adjacentes permitem identificar trechos com predomínio de processos agradacionais e denudacionais nos sistemas fluviais. Este trabalho identifica trechos dos perfis longitudinais dos rios a montante do Parque Estadual de Terra Ronca, no nordeste do estado de Goiás, que possuem tendências diferentes para transferência de sedimentos para jusante. Os rios cujos perfis longitudinais mais atenuam o potencial de transferência de sedimentos são: o São Vicente, da Lapa e Angélica. A forma dos perfis e a distribuição das planícies aluviais estão intrinsecamente ligados aos compartimentos geomorfológicos da área do Parque Estadual de Terra Ronca e à evolução do relevo regional, influenciando o transporte de sedimentos da rede de drenagem.The Role of the Longitudinal Profile in the attenuation of the Potential of Transport of Sediments in Watersheds: the case of the Terra Ronca State Park (GO), Brazil A B S T R A C TThe shape of the longitudinal profiles of rivers associated with the distribution of the adjacent floodplains allows identifying sections with predominance of aggradational and denudational processes in the fluvial systems. This paper identifies stretches of the longitudinal profiles of the rivers upstream of the Terra Ronca State Park, in the northeast of the state of Goiás, which have different trends to transfer of sediments to downstream. The rivers whose longitudinal profiles more attenuate the sediment transfer potential are: São Vicente, Lapa and Angélica. The shape of the profiles and the distribution of alluvial plains are intrinsically linked to the geomorphological compartments of the Terra Ronca State Park’s area and the evolution of the regional relief, influencing the sediment transportation of the fluvial drainage network.Keywords: sediment transportation, alluvial plains, geomorphological compartmentation.
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ŠORŠA, Ajka, Teja ČERU, Zsófia KOVÁCS, Gyozo JORDAN, Katalin Mária DUDÁS, and Peter SZABÓ. "ASSESSMENT OF RIVER SEDIMENT QUALITY ACCORDING TO THE EU WATER FRAMEWORK DIRECTIVE IN LOWLAND FLUVIAL CONDITIONS. A CASE STUDY IN THE DRAVA RIVER AREA, DANUBE RIVER BASIN." Carpathian Journal of Earth and Environmental Sciences 17, no. 2 (2022): 459–68. http://dx.doi.org/10.26471/cjees/2022/017/235.
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The EU Water Framework Directive requires the monitoring and evaluation of surface water sediment quality based on the assessment of risk posed by contamination on the biotic receptors. Fluvial sediments are important receptors of hazardous substances (HSs) pollution from the upstream catchment areas in the Danube River Basin (DRB). For the development of systematic sediment quality monitoring and evaluation, the Drava River region on the border of Hungary and Croatia was selected as a test area representative of lowland hydromorphological conditions. Overbank (floodplain) sediments and river bottom sediments (stream sediments) were sampled at two depths at 9 locations in the test area. Eight heavy metal(oid)s were analyzed As, Cd, Cr, Cu, Hg, Ni, and Zn as hazardous substances. The sediment quality assessment was carried out according to the 2013/39/EU Directive and EU Water Framework Directive standards. Most of the analysed HS concentrations in river bottom sediment and overbank (floodplain) sediments fall within the limits of environmental quality standards (EQS). Results show that there is no significant differences in metal(oid) HS concentrations among the various sediment types and between shallow (0-5cm) and deeper (stream sediment: 5-10cm; floodplain sediment: 40-50cm) sediment which suggests that the large lowland Drava River fluvial system is an extensive single fluvial system with homogeneous distribution of sediments and the associated contaminants. Specifically, the studied sediments in the tributaries of the Drava River do not seem to be contaminated with metal(oid) hazardous substances but at certain sites concentrations are elevated above the environmental limit values, especially for As and Zn, and to lesser extent for Cr. The data analysis techniques used enabled the identification of sites with anthropogenic pollution and the recognition of regional pattern in HSs distribution.
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Chang, Chang Shen, A. H. Yusoff, C. A. R. Mohamed, et al. "Geochemistry of Rare Earth Elements in Pahang River Sediment, Malaysia." Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 331, no. 4 (2024): 42–50. http://dx.doi.org/10.31643/2024/6445.37.
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Rare earth elements (REE) are a set of 17 chemically similar metallic elements including 15 lanthanides, scandium and yttrium. The current status of REE as a global strategic commodity has encouraged the identification of REE ore deposits. This research is carried out to identify the mining feasibility of fluvial sediment REE and to understand the sediment's physical and chemical characteristics and effects on the geochemical behaviour of REE in the longest river of Peninsular Malaysia namely Pahang River. Surface sediment samples were collected along Pahang River (n=44) in approximately 10 km distance intervals. The sediment samples were analyzed using XRF to determine the major oxide content. Meanwhile, REE content in the sediment samples was extracted using the Total Digestion method and analysed using ICP-MS. The results show the average value of ΣREE at surface sediments of the Pahang River is 42.58 ppm and can be considered too low to be economically mined. Each area shows higher fractionation of light REE than heavy REE with negative europium anomalies, suggesting sediments in this area were derived from felsic rocks. The concentration of REE in Pahang River surface sediments was controlled by the porosity and organic matter as showed by the correlation of ΣREE with porosity (R2=0.65) and organic matter content (R2=0.71). In conclusion, this research's findings are generally useful for further REE mineral exploration and fluvial sediment environmental monitoring.
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Omoboh, Jonathan Obukowho, Minapuyi I. Odigi, and Kingsley O. Okengwu. "Depositional Processes, Facies and Environment of Deposition of the Upper Miocene (Seravillian/Tortonian) Sediments in the Jokg Field – Eastern Niger Delta." Journal of Scientific and Engineering Research 9, no. 2 (2022): 28–33. https://doi.org/10.5281/zenodo.10510505.
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<strong>Abstract </strong>This work aim to identify the depositional environments of the Seravillian/Tortonian sediments of the coastal swamp depobelt in the Niger Delta basin through the features preserved in the facies by depositional processes. The vertical change in grain size - a product of change in energy of the depositional processes preserved in the identified facies was employed to identify the depositional process (s) that generate the facies. The change in grain size was identified from the gamma ray log trend which have been known to correlate and calibrated with grain size changes. The interval studied within the upper Miocene in the “JOKG” Field, reveals that the sediments were deposited by fluvial processes (erosion, transport, sediment supply and deposition) and shoreline processes (sediment supply, transport, deposition, wave and tidal current redistribution of deposited sediments). The upper section of the interval is dominated by fluvial processes as it contains predominately of sediments which fines upward and sometimes blocky in log trend. The lower part is characterized by sediments which fine downward and coarse upwards with occasional occurrence of sediments that fine upwards. These represents shoreline processes which were occasionally interrupted with fluvial processes. The dominant of the fluvial processes in the upper section show that continental environment occur in the upper section while transitional to shallow marine environment occur in the lower part, since these processes are predominant in these environments respectively. This work thus helps to identify a depositional environment from the predominant of identified processes producing its facies.
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Retelle, Michael J. "Stratigraphy and Sedimentology of Coastal Lacustrine Basins, Northeastern Ellesmere Island, N. W. T." Géographie physique et Quaternaire 40, no. 2 (2007): 117–28. http://dx.doi.org/10.7202/032632ar.
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ABSTRACT Sediment cores recovered from three high arctic coastal lake basins contain a sequence of glaciomarine sediments overlain by laminated to massive-bedded lacustrine sediments. Glaciomarine sediments were deposited while the basins were isostatically depressed below sea level. Subsequent to emergence of the basin from the sea, lacustrine sediments accumulated in each basin. A transitional fades between the marine and lacustrine units represents an isolation interval during which trapped sea water lay beneath a freshwater lens. Sedimentological and faunal evidence from sediment cores demonstrates that embayments were closed and fluvial sedimentation was minimal during the glacial maximum (ca. 8000-8200 BP) Subsequent increases in sand content and macrofaunal abundance reflects increases in mobility of sea ice and fluvial input during the middle Holocene. Late HoIocene cooling trends are demonstrated by decreases in ice rafted material and an increase in diffuse bedding in lake surface sediments.
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de Jalón, Diego García, Martina Bussettini, Massimo Rinaldi, et al. "Linking environmental flows to sediment dynamics." Water Policy 19, no. 2 (2016): 358–75. http://dx.doi.org/10.2166/wp.2016.106.
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This is a policy discussion paper aimed at addressing possible alternative approaches for environmental flows (e-Flows) assessment and identification within the context of best strategies for fluvial restoration. We focus on dammed rivers in Mediterranean regions. Fluvial species and their ecological integrity are the result of their evolutionary adaptation to river habitats. Flowing water is the main driver for development and maintenance of these habitats, which is why e-Flows are needed where societal demands are depleting water resources. Fluvial habitats are also shaped by the combined interaction of water, sediments, woody/organic material, and riparian vegetation. Water abstraction, flow regulation by dams, gravel pits or siltation by fine sediments eroded from hillslopes are pressures that can disturb interactions among water, sediments, and other constituents that create the habitats needed by fluvial communities. Present e-Flow design criteria are based only on water flow requirements. Here we argue that sediment dynamics need to be considered when specifying instream flows, thereby expanding the environmental objectives and definition of e-Flows to include sediments (extended e-Flows). To this aim, a hydromorphological framework for e-Flows assessment and identification of best strategies for fluvial restoration, including the context of rivers regulated by large dams, is presented.
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Marren, Philip M. "Sedimentology of proglacial rivers in eastern Scotland during the Late Devensian." Transactions of the Royal Society of Edinburgh: Earth Sciences 92, no. 2 (2001): 149–71. http://dx.doi.org/10.1017/s0263593300000110.
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ABSTRACTThis paper reconstructs the characteristics of rivers which deposited proglacial fluvial sediments in east-central Scotland during the Late Devensian. Sediment depositional architecture and geometry, together with the relationship between high-stage and falling and low-stage depositional elements, were used to relate the proglacial sediments to the glacial meltwater discharge regime. The proglacial river systems studied were dominated by ‘normal’ ablation controlled discharge, rather than by high magnitude flood events. Consequently there is a great deal of spatial and vertical variability. Deposition occurred during short intervals of rapid aggradation, so that relatively fine-grained falling-stage sediments, as well as coarser, bar-core sediments are well preserved. Models relating the characteristics of the final deposit to the nature of the river are presented. These emphasise the role of stage changes and aggradation rates in controlling sediment architecture in braided fluvial deposits.
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Hori, Kazuaki, Susumu Tanabe, and Atsushi Urabe. "Accumulation of thick fluvial sediments in the Shinano River incised-valley fills: implications for sequence stratigraphy and alluvial architecture." Journal of Sedimentary Research 93, no. 7 (2023): 453–62. http://dx.doi.org/10.2110/jsr.2022.049.
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ABSTRACT The relationship between fluvial systems and base-level changes, controlled mainly by sea-level fluctuations and tectonic activity, on time scales of 103–104 years, is important for evaluating and improving nonmarine sequence stratigraphy and numerical and physical alluvial architecture models. However, there are not enough quantitative data available from field studies, especially for periods of rapid base-level rise. The Echigo Plain, Japan, is a fluvial–coastal lowland where the tidal range is very small and where a very deep valley was incised by the Shinano River during the latest Pleistocene. The depth of the incised valley near the shoreline, 160 m below mean sea level, is greater than the amount of sea-level fall during the Last Glacial Maximum (LGM) because of tectonic subsidence. We studied an approximately 100-m-long borehole sediment core obtained from the landward part of the plain, where thick fluvial deposits have accumulated since the LGM. Sediment facies, diatom assemblages, sulfur content, carbon to sulfur ratios, and radiocarbon age dates indicate that most of the core sediments were deposited in a fluvial environment during the past 12 kyr. Sediment accumulation rates were 10–15 m/kyr between 12 and 8 cal kyr BP, and relatively low (less than 5 m/kyr) subsequently, mainly because of glacio-eustatic sea-level rise. The timing of the reduction in the accumulation rate is one possible indicator of the position of the maximum-flooding surface in a sequence composed only of fluvial sediments. The presence of many thin layers of very fine to fine-grained sand (20–80 cm thick), interpreted as crevasse-splay deposits, that formed between 11 and 8 cal kyr BP, when the base level was rising rapidly, implies that crevasse-splay deposits are characteristic of aggrading fluvial sediments and the transgressive systems tract in nonmarine sequence stratigraphy. Tectonic subsidence at approximately 2 m/kyr has contributed markedly to the larger accumulation rate of fluvial sediments of the highstand systems tract on the Echigo Plain, compared with rates in other fluvial–coastal lowlands, since 5–6 cal kyr BP, when the eustatic sea-level rise had mostly ceased.
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Li, Fuqiang, Baotian Pan, Zhongping Lai, Hongshan Gao, and Xianjiao Ou. "Identifying the degree of luminescence signal bleaching in fluvial sediments from the Inner Mongolian reaches of the Yellow River." Geochronometria 45, no. 1 (2018): 82–96. http://dx.doi.org/10.1515/geochr-2015-0087.
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Abstract The partial bleaching of the luminescence signal prior to deposition results in age overestimation, and can be a problem in delineating fluvial evolution within an OSL chronological framework. The Inner Mongolian reaches of the Yellow River are characterised by a high sediment load and complex sources of sediments. To test the incomplete bleaching occurring in this type of environment, the residual doses and the luminescence signal characteristics of different particle size fractions from 14 modern fluvial sediment samples were investigated. Furthermore, 26 OSL ages derived from drilling cores were compared with 11 radiocarbon ages. Our results show that the residual equivalent doses principally range between 0.16 and 0.49 Gy for silt grains, and between 0.35 and 3.72 Gy for sand grains of modern samples. This suggests that medium-grained quartz has been well bleached prior to deposition, and is preferable to coarse-grained quartz when dating fluvial sediments in this region. The results also show that the De values of coarse-grained fractions display a stronger correlation with distance downstream. In addition, a comparison of OSL and radiocarbon ages from drilling cores establishes further confidence that any initial bleaching of these sediments was sufficient. As a result, we believe that the studied fluvial samples were well bleached prior to deposition.
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Bomer, Edwin J., Carol A. Wilson, and Dilip K. Datta. "An Integrated Approach for Constraining Depositional Zones in a Tide-Influenced River: Insights from the Gorai River, Southwest Bangladesh." Water 11, no. 10 (2019): 2047. http://dx.doi.org/10.3390/w11102047.
Full textAbstract:
The tidal to fluvial transition (TFT) of estuaries and coastal rivers is one of the most complex environments on Earth with respect to the transportation and deposition of sediment, owing in large part to competing fluvial and marine processes. While there have been recent advances in the stratigraphic understanding of the TFT, it is still unclear whether these findings are site-specific or representative of mixed tidal-fluvial systems worldwide. Yet, research from this depositional domain holds profound societal and economic importance. For instance, understanding the underlying stratigraphic architecture of channel margins is critical for assessing geomorphic change for fluvio-deltaic settings, which are generally vulnerable to lateral channel migration and resultant erosion. Findings would also benefit paleo-geographic reconstructions of ancient tide-influenced successions and provide an analog for hydrocarbon reservoir models. In the Ganges-Brahmaputra Delta of Bangladesh, the Gorai River is one of two Ganges distributaries actively connected to the Bay of Bengal. With fluvial input from the Ganges and meso-scale (2–4 m range) tides at the coast, the Gorai exhibits a variety of hydrodynamic regimes across its 350-km reach, providing a unique opportunity to investigate along-channel depositional patterns across the TFT. This study integrates multiple datasets—core sedimentology, river channel bathymetry, and remote sensing—to provide a process-based framework for determining the relative position of sedimentary deposits within the tidal-fluvial continuum of the Gorai River. The results of this investigation reveal coincident, abrupt shifts in river channel morphology and sediment character, suggesting the occurrence of backwater-induced mass extraction of relatively coarse sediments (i.e., fine sand). Despite being situated in an energetic tidal environment, evidence of tidal cyclicity in cored sediments is relatively rare, and the bulk stratigraphy appears strongly overprinted by irregularly spaced cm- to dm-scale sediment packages, likely derived from monsoonal flood pulses. Such findings differ from previously-studied mixed tidal-fluvial systems and underscore the site-specific complexities associated with this depositional domain.
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Pailles, C., and PW Moody. "Phosphorus sorption-desorption by some sediments of the Johnstone Rivers catchment, northern Queensland." Marine and Freshwater Research 43, no. 6 (1992): 1535. http://dx.doi.org/10.1071/mf9921535.
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Phosphorus (P) sorption-desorption characteristics were determined for 11 sediments from the Johnstone Rivers catchment, northern Queensland. Sediments were selected to cover a range in values of Bray extractable P from 0.1 to 10.4 mg P kg-1. P sorption curves were determined by using 0.01 M NaCl to simulate fluvial water conditions and, on a restricted number of sediments, 0.5 M NaCl to simulate sea water. The amounts of P released in 10 successive extractions for 30 min with 0.01 M CaCl2 were determined for each sediment. The amounts of P desorbed either declined to nondetectable levels or declined to a constant amount. These desorption curves were used to delineate 'rapidly desorbable' P from 'slowly desorbable' P. Bray extractable P and adsorption characteristics (equilibrium solution P concentration and P buffer capacity) were poorly correlated with 'rapidly desorbable' P. Most sediments in the suite would act as P sinks in both fluvial and marine environments because their equilibrium P concentrations are lower than the dissolved inorganic P concentrations of their respective water columns. For those sediments acting as potential sources (5 from 11 in 0.01 M NaC1, 2 from 6 in 0.5 M NaCl), amounts of P that could potentially be desorbed into the fluvial water column ranged from 0.1 to 3.9 mg P kg-1 sediment.
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Sidorchuk, A. Yu. "THE FLUVIAL SYSTEM ON THE EAST EUROPEAN PLAIN: SEDIMENT SOURCE AND SINk." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 11, no. 3 (2018): 5–20. http://dx.doi.org/10.24057/2071-9388-2018-11-3-05-20.
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The modern fluvial system on the lowland East European Plain is of depositional type. Sediment transport to the seas is only a few percent of the total erosion, and the main part of eroded material is accumulated in the channels. The recent deposition of suspended sediments is caused by accelerated soil erosion on the arable slopes, which led to a high rate of lateral sediment input and deposition at the river headwaters and on the floodplains. The process of accumulation is facilitated by the unfilled “negative” volume of the net of dry valleys formed during the Late Glacial catastrophic erosion event. Such events of catastrophic erosion of the sediments deposited in the lowland fluvial systems occur with a frequency of 100-120 thousand years. In the conditions of both scarce vegetation and extremal surface runoff, the entire fluvial systems become the area of intensive erosion, with the deep incision of gullies and of the river channels. Therefore, despite the modern intensive deposition, delivery ratio for the fluvial systems on this lowland territory is close to one in the long-term perspective.
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Liu, Fenliang, Hongshan Gao, Zongmeng Li, Changjun Huang, Zhen Xi, and Yun Xue. "Geochronological and Sedimentological Study of the Fluvio-Lacustrine Deposits from Shigu to Longjie: Implications for the Evolution of the Lower Jinsha River since the Early Pleistocene." Water 15, no. 20 (2023): 3613. http://dx.doi.org/10.3390/w15203613.
Full textAbstract:
The formation of the Jinsha River drainage is a significant subject of concern in the geological and geomorphological fields. Among them, one key question is whether there was a regional paleo lake into which Lower Jinsha River drainage drained during the late Pliocene to early Pleistocene, due to massive fluvio-lacustrine sediments widely distributed in the Lower Jinsha River. Nevertheless, there has yet to be a consensus on the genesis of those fluvio-lacustrine sediments due to poor sedimentological and chronological data. In this study, to unravel the origin of those fluvio-lacustrine sediments and the formation model of the Lower Jinsha River, sedimentary characteristics, including spatial distribution, lithological composition, and stratigraphic contact relationship of those fluvio-lacustrine sediments were analyzed, and chronological determination of the fluvio-lacustrine sediments using Electron Spin Resonance and Optically stimulated luminescence method was conducted. The results show that in the Lower Jinsha River, the lacustrine sediments are mainly composed of silt and clay, with apparent horizontal bedding, stacked with fluvial cobble-gravel and sand, and are in unconformable contact with the underlying bedrock strata or paleo soil. The lacustrine sediments are spatially discontinuous and mainly distributed in the Shigu, Taoyuan, Panzhihua, and Longjie reaches. Downstream of these reaches are deeply incised gorges with an average slope >30°, and many landslide landforms and deposits can be identified here. In each reach, the lacustrine sediments were closely distributed along the trunk and tributary channels in the plane and were distributed at different altitudes, forming a sequence of lacustrine terraces. Chronological analysis shows that in different reaches, the deposition ages of lacustrine sediments are significantly different. In each reach, the deposition age of the lacustrine terraces of high altitude is older than that of low altitude. The above characteristics collectively indicate that the lacustrine sediments in the Lower Jinsha River were locally deposited by individual dammed lakes, probably induced by landslide rather than a regional paleo lake by tectonic activities. During the incision process of the river valley, landslides continuously block the river channel, forming dammed lakes, and then deposited lacustrine sediments at different elevations, forming lacustrine terraces. The lacustrine sediment of the topmost lacustrine terrace in Panzhihua reach was dated to be 1.78 Ma, combined with previous studies on the fluvial terraces, indicating the Lower Jinsha River existed and started to incise its valley before the early Pleistocene. The widespread dammed lake sediment indicates that the formation of the Jinsha River valley follows the pattern of “incision-landslide-damming-aggradation-incision”.
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ETOBRO, Israel Aruoriwo Abiodun, Omabehere Innocent Ejeh, and Glory Oghenevwede Ovwamuedo. "FLUVIAL SEDIMENTOLOGY OF THE RIVER ETHIOPE SEDIMENTS, NIGER DELTA, SOUTHERN NIGERIA." Rudarsko-geološko-naftni zbornik 39, no. 2 (2024): 45–61. http://dx.doi.org/10.17794/rgn.2024.2.4.
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Despite modern advances in the study of rivers globally, there remains a plethora of work to be done especially in the area of fluvial sedimentology of some present-day river systems. Previous studies on fluvial sedimentology of the sediments of the river Ethiope (in southern Nigeria) are meagre. Grain size analytical methods are indispensable to infer siliciclastic sediments' hydrodynamic conditions, transportation mode(s), and sedimentary environments. Twenty-eight samples (n=28) of the river Ethiope sediments were selected and studied using granulometric analyses (mechanical sieving and pebble morphometric methods). The granulometric analyses results revealed that the obtained sediments were comprised of 82.75% sand, 9.33% gravel, and 7.92% mud. A ternary diagram of sand-gravel-mud shows the sediments are mainly gravelly sand, with few indicating slightly gravelly sand, gravelly muddy sand, muddy sand, and sandy gravel. The grain size statistical analysis shows that the river Ethiope sediments consist of medium to coarse, poorly-sorted to moderately well-sorted, strongly coarse skewed to strongly fine skewed, and very platykurtic to extremely leptokurtic sands. The pebble morphometric analysis revealed that the pebbles range in shape from bladed (B) 22%, compact-bladed (CB) 17%, compact (C) 16%, compact-platy (CP) 16%, compact-elongated (CE) 12%, platy (P) 5%, to elongated (E) 5%. The integration of bivariate plots, ternary diagrams, and C-M patterns plotted for the sediments of the river Ethiope indicated a fluvial environment with sediments characterised by low to moderately high energy that transport sediments of different sizes and grades through saltation, traction, and suspension modes. This study also confirms that sediment transport modes such as saltation, traction, and suspension typify river environments. In general, the existing sedimentologic models derived from grain size analysis of sediments and pebble morphometric methods obtained from modern-day rivers can be applied to better understand transport modes, sedimentary processes, and palaeoenvironments of their ancient counterparts.
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Adiotomre, Emmanuel E., Innocent O. Ejeh, and Edwin O. Adaikpoh. "Geochemistry of Fluvial Sediments from Geregu, Southwest Nigeria." Materials and Geoenvironment 64, no. 1 (2017): 35–52. http://dx.doi.org/10.1515/rmzmag-2017-0004.
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Abstract Geochemical analysis of fluvial sediments on the banks of River Ero using inductively coupled plasma mass spectrometry illustrates their maturity, provenance and tectonic setting. The analysed sediment samples show low SiO2/Al2O3 ratios of 2.92-2.99 (units FL_A, FL_B and FL_E) and high SiO2/Al2O3 ratios of 4.064-4.852 (units FL_C, FL_D, FL_F and FL_G). Sediments were geochemically classified as shales (units FL_A, FL_B and FL_E) and greywackes (units FL_C, FL_D, FL_F and FL_G). Variability in sediment maturity (FL_F > FL_G >FL_C >FL_D >FL_A > FL_B > FL_E) parallels a decreasing order in the ratios of SiO2/Al2O3 and K2O/Al2O3, as well as the proportion of quartz grains and matrix components. Evidence from Al2O3/TiO2, K2O, Rb, La/Co, Th/Co, Cr/ Th, Th/Cr, La/Th-Hf, Th-Hf-Co and rare earth element contents of sediment samples suggest felsic protoliths of upper continental crust in a passive margin tectonic setting. An insignificant contribution of mafic components from the source is, however, inferred based on the Ni and Cr contents of the sediment samples. Combined Eu anomalies <0.85 and (Gd/Yb)n ratios <2.0 (1.53- 1.82, average 1.65) suggest post-Archean protoliths.
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Personius, Stephen F., Harvey M. Kelsey, and Paul C. Grabau. "Evidence for Regional Stream Aggradation in the Central Oregon Coast Range during the Pleistocene-Holocene Transition." Quaternary Research 40, no. 3 (1993): 297–308. http://dx.doi.org/10.1006/qres.1993.1083.
Full textAbstract:
AbstractLow, nearly continuous terraces of similar age are present along streams in drainage basins that range in size from Drift Creek (190 km2) to the Umpqua River (11,800 km2) in the Oregon Coast Range. Radiocarbon ages from near the bose of fluvial sediments underlying these terraces are clustered at about 9000-11,000 14C yr B.P. Beveled bedrock surfaces (straths) that underlie the fluvial sediments are 1-8 m above summer stream levels and are present along most of the nontidal reaches of the rivers that we studied. Where exposed, the bedrock straths are overlain by 2-11 m of fluvial sediment that consists of a bottom-stratum (channel) facies of sandy pebble-cobble gravel and a top-stratum (overbank) facies of sandy silt or silt. Eight radiocarbon ages from the fluvial sediments allow correlation of the lowest continuous terrace over a wide area and thus indicate that a regional aggradation episode occurred in Coast Range drainage basins during the Pleistocene-Holocene transition. The cause of such widespread aggradation is unknown but may be related to climate-induced changes in the frequency of evacuation of colluvium from hollows, which are common in all drainage basins in the region.
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Hein, Frances J., James P. M. Syvitski, Lynda A. Dredge, and Bernard F. Long. "Quaternary sedimentation and marine placers along the North Shore, Gulf of St. Lawrence." Canadian Journal of Earth Sciences 30, no. 3 (1993): 553–74. http://dx.doi.org/10.1139/e93-043.
Full textAbstract:
Offshore areas, along the North Shore of the St. Lawrence Estuary, have major lithostratigraphic and seismostratigraphic units that relate to the advance or retreat of the Late Wisconsinan Ice Sheet, subsequent marine transgression or regression, and reworking of postglacial deposits. Glacial diamicton and glaciomarine units (acoustic units 1 and 2) were emplaced between >18 and 14.5 ka, by basal meltout or ice-marginal sedimentation; they reflect ice-proximal sedimentation associated with ice-terminal stillstands. Deep-water muds (acoustic unit 3) represent ice-distal accumulation of glaciomarine sediment from glaciofluvial plumes between 13.5 and 11 ka. After this time exceptionally thick nearshore coarse-grained deltaic and estuarine successions (acoustic unit 4) were deposited. The uppermost postglacial sediment (acoustic unit 5) forms the seabed and reflects a reworking phase concomitant with a lowering sea level and ablating Late Wisconsinan ice sheets.Glacioisostatic rebound, which occurred about 23 ka to the present, uplifted glacial and marine deposits and resulted in extensive reworking and production of modern placers. Heavy-mineral concentrations vary as follows: terrestrial tills, 9–20%; modem storm-berm and delta top deposits, 43–60%; delta slope deposits, 25–55%; and deep (170+ m) offshore sediments, 0–2%. Three stages occurred in marine placer formation: (1) 6700 BP, fluvial discharge was high, and fluvial-dominated deltas were built; marine limit was 30 m asl, with progradation of deltas and delivery of sediments with at most 2% heavy minerals; (2) 5200 BP, fluvial discharge was reduced; marine limit was 15 m asl, deltaic sediments were reworked, increasing heavy mineral concentration to 2–8%; (3) 2800 BP, fluvial input was greatly reduced, waves and tides were more influential, a strong littoral current system developed, causing significant reworking of nearshore sediments, heavy mineral concentrations increased, with values exceeding 20% locally. Mass budget calculations show that the second-cycle reworked sediment (acoustic unit 5) is a potential economic target (1 km3, or 1700 Mt). If 7% (using atomic weights) of this target sediment is ilmenite (FeTiO3). then 27 Mt of titanium may be available.
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Suandhi, P. A., M. Rozalli, W. Utomo, A. Budiman, and A. Bachtiar. "Paleogene Sediment Character of Mountain Front Central Sumatra Basin." Indonesian Journal on Geoscience 8, no. 3 (2013): 143–49. http://dx.doi.org/10.17014/ijog.8.3.143-149.
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DOI: 10.17014/ijog.v8i3.164The SE-NW trending Mountain Front of Central Sumatra Basin is located in the southern part of the basin. The Mountain Front is elongated parallel to the Bukit Barisan Mountain, extending from the Regencies of North Padang Lawas (Gunung Tua in the northwest), Rokan Hulu, Kampar, Kuantan Singingi, and Inderagiri Hulu Regency in the southeast. The Palaeogene sediments also represent potential exploration objectives in Central Sumatra Basin, especially in the mountain front area. Limited detailed Palaeogene sedimentology information cause difficulties in hydrocarbon exploration in this area. Latest age information and attractive sediment characters based on recent geological fieldwork (by chaining method) infer Palaeogene sediment potential of the area. The Palaeogene sedimentary rock of the mountain front is elongated from northwest to southeast. Thickness of the sedimentary unit varies between 240 - 900 m. Palynology samples collected recently indicate that the oldest sedimentary unit is Middle Eocene and the youngest one is Late Oligocene. This latest age information will certainly cause significant changes to the existing surface geological map of the mountain front area. Generally, the Palaeogene sediments of the mountain front area are syn-rift sediments. The lower part of the Palaeogene deposit consists of fluvial facies of alluvial fan and braided river facies sediments. The middle part consists of fluvial meandering facies, lacustrine delta facies, and turbidity lacustrine facies sediments. The upper part consists of fluvial braided facies and transitional marine facies sediments. Volcanism in the area is detected from the occurrence of volcanic material as lithic material and spotted bentonite layers in the middle part of the mountain front area. Late rifting phase is indicated by the presence of transitional marine facies in the upper part of the Palaeogene sediments.
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Demurtas, Luca, Luigi Bruno, Stefano Lugli, and Daniela Fontana. "Evolution of the Po–Alpine River System during the Last 45 Ky Inferred from Stratigraphic and Compositional Evidence (Ostiglia, Northern Italy)." Geosciences 12, no. 9 (2022): 342. http://dx.doi.org/10.3390/geosciences12090342.
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The stratigraphic and compositional study of three sediment cores recovered close to the Po River near Ostiglia provides clues on changes in fluvial dynamics at the transition from the last glacial to the present interglacial. Upper Pleistocene units are dominated by sands with high content in volcanic lithics, denoting high sediment supply from the south-Alpine fluvio-glacial tributary system. The Early–Mid Holocene unit, peat-rich and barren in fluvial sands, results from low sediment supply and waterlogging, encompassing the maximum marine ingression. The Late Holocene unit, characterized by fluvial-channel sands with lower content in volcanics and relatively abundant metamorphic lithics, records the Po River sedimentation since the Late Bronze Age. Late Holocene sands show a lower content in siliciclastic lithic fragments (supplied mainly by Apennine tributaries) compared to modern Po River sands. This distinctive composition could reflect the diversion of Apennine sediments into a southern Po River branch during the Late Bronze Age and into an Apennine collector flowing south of Ostiglia during Roman times and the Middle Ages. The integrated stratigraphic-compositional methods used in this study permitted to reconstruct the major climate-related changes in sediment dispersal and may be potentially applied to other alluvial and coastal settings.
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Shi, Wei, Hanchao Jiang, Hongyan Xu, et al. "Response of modern fluvial sediments to regional tectonic activity along the upper Min River, eastern Tibet." Earth Surface Dynamics 10, no. 6 (2022): 1195–209. http://dx.doi.org/10.5194/esurf-10-1195-2022.
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Abstract. The deposition of fluvial sediments in tectonically active areas is mainly controlled by tectonics, climate, and associated Earth surface processes; consequently, fluvial sediments can provide a valuable record of changes in regional climate and tectonic activity. In this study, we conducted a detailed analysis of the grain-size distribution in modern fluvial sediments from the upper Min River, eastern Tibet. These data, combined with information on regional climate, vegetation, hydrology, geomorphology, lithology, and fault slip rate, indicate that modern regional tectonic activity along upper Min River can be divided into three segments. Specifically, fluvial sediments in the Minjiangyuan–Diexi segment are dominated by silts (< 63 µm, 70.2 %), agreeing with low runoff, low rainfall, and high vegetation cover and revealing a windblown origin influenced by the arid and windy climate. These observations are consistent with the low hillslope angle and low relief, all indicating weak activity along the Minjiang Fault. The coarse-grained fraction (> 250 µm) of fluvial sediments in the Diexi–Wenchuan and Wenchuan–Dujiangyan segments increases stepwise downstream, although runoff and rainfall do not change significantly. These patterns correlate well with increases in both regional relief and hillslope angles. Together, these observations imply that regional tectonic activity along the Maoxian–Wenchuan Fault becomes more pervasive downstream along the Min River. The occurrence of well-sorted and well-rounded pebbles of fluvial sediments downstream of Dujiangyan must be related to the long-time scouring and sorting by rivers. This study marks the first development of a new research approach that can characterize regional tectonic activity by analysis of grain-size distribution of fluvial sediments collected from tectonically active regions.
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Nicholson, Uisdean, Andrew Carter, Paula Robinson, and David I. M. Macdonald. "Eocene–Recent drainage evolution of the Colorado River and its precursor: an integrated provenance perspective from SW California." Geological Society, London, Special Publications 488, no. 1 (2018): 47–72. http://dx.doi.org/10.1144/sp488-2019-272.
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AbstractThe Colorado River in the SW of the USA is one of Earth's few continental-scale rivers with an active margin delta. Deformation along this transform margin, as well as associated intra-plate strain, has resulted in significant changes in sediment routing from the continental interior and post-depositional translation of older deltaic units. The oldest candidate deposits, fluvial sandstones of the Eocene Sespe Group, are now exposed in the Santa Monica Mountains, 300 km to the north of the Colorado River. Heavy mineral data from this basin indicate that sediment was sourced by a large river system, with some affinity to the early Pliocene Colorado River, but was unlikely to have been integrated across the Colorado Plateau. Sedimentological and mineralogical evidence from the earliest (c. 5.3 Ma) unequivocal Colorado River-derived sediments in the Salton Trough provide evidence for a rapid transition from locally derived sedimentation. Lack of evidence for a precursor phase of suspended-load sediment suggests that drainage capture took place in a proximal position, favouring a ‘top-down’ process of lake spillover. Following drainage integration, significant changes in heavy mineral assemblages of fluvio-deltaic sediments, particularly evident from apatite–tourmaline and garnet–zircon indices, as well as U–Pb ages of detrital zircons, document the integration of the fluvial system to its present form and progressive incision of the Colorado Plateau from the Miocene to the present.
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Désy, JC, J. F. Archambault, B. Pinel-Alloul, J. Hubert, and P. GC Campbell. "Relationships between total mercury in sediments and methyl mercury in the freshwater gastropod prosobranch Bithynia tentaculata in the St. Lawrence River, Quebec." Canadian Journal of Fisheries and Aquatic Sciences 57, S1 (2000): 164–73. http://dx.doi.org/10.1139/f99-231.
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Total Hg concentrations in sediment and methyl mercury (MeHg) levels in the gastropod species Bithynia tentaculata were evaluated at 21 stations in the fluvial corridor of the St. Lawrence River (Quebec, Canada). In the sediments (n = 21), total Hg concentrations ranged from 34 to 2790 ng·g dry weight-1. In the gastropods, MeHg concentrations varied from 15 to 290 ng·g dry weight-1 in undepurated gastropods (n = 20) and from 41 to 420 ng·g dry weight-1 in depurated gastropods (n = 13; without gut contents). The southern sector of Lake St. Louis, located near the Îles-de-la-Paix, had significantly higher Hg concentrations than any other sectors under study, both for total Hg in the sediments and MeHg in the gastropods. We established linear models to describe the relationships between Hg contamination in sediments and molluscs for the fluvial corridor of the St. Lawrence River and for the Lake St. Louis sector. Total Hg in sediments and MeHg in gastropods were highly correlated for all pooled stations (r = 0.83), and the relationship was even stronger for the Lake St. Louis stations (r = 0.92). Our study suggests that the gastropod B. tentaculata is a promising biomonitor species for assessing Hg contamination in the fluvial corridor and lakes of the St. Lawrence River.
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Jones, MR. "Surficial sediments of the western Gulf of Carpentaria, Australia." Marine and Freshwater Research 38, no. 1 (1987): 151. http://dx.doi.org/10.1071/mf9870151.
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Modern sedimentation in the Gulf of Carpentaria is confined principally to marginal areas in water depths of less than 50 m. Within this zone, the distribution of sediments is irregular, being controlled by proximity to sediment sources and degree of exposure to waves and tidal activity. This is particularly so in the western gulf, where fluvial sediments supplied to Limmen Bight have been transported by waves and tides northwards beyond that embayment to accumulate in the sheltered environment of Blue Mud Bay. Limmen Bight is exposed to the south-easterlies, which produce sufficient wave action in the nearshore zone to prevent the widespread deposition of fine-grained terrigenous sediments. As a result, relict sand deposits occupy much of the floor of Limmen Bight in areas shallower than about 25 m. In deeper areas, terrigenous muds are deposited at a low rate over relict fluvial and marine sediments. The relict deposits accumulated in continental and nearshore marine environments during low-sea-level periods of the late Pleistocene.
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Álvarez-Vázquez, Miguel Ángel, and Elena De Uña-Álvarez. "An exploratory study to test sediments trapped by potholes in Bedrock Rivers as environmental indicators (NW Iberian Massif)." Cuaternario y Geomorfología 35, no. 1-2 (2021): 59–77. http://dx.doi.org/10.17735/cyg.v35i1-2.89054.
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The capacity of fluvial potholes to trap sediments, together with the geochemical analysis of their stored sediments for environmental assessment, is an overlooked research topic in small bedrock rivers. The present exploratory study is focused on this issue. It was developed in a small river over rock, in the inland territory of Galicia (NW Iberian Peninsula). The study started from an analysis of the inventoried fluvial potholes to identify suitable forms for sampling, and the collection of sediment samples within them. After this, the determination of the grain texture, mineralogy and content of major and trace elements in sediments were carried out. Potholes with maximum vertical depth from 25 cm to 1 m, located in central and sidewall sectors of the bedrock channel, provided the best conditions for sediment sampling. The sediments collected from six potholes showed predominance of coarse-medium grain size and sand fraction. The rough contents of the major and even trace elements are related with the nature of the more refractory minerals of the bedrock. An adequate sampling strategy, considering grain-size fractions, show potential to use trace elements as environmental indicators.
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QUINTERO, Daniela I., de AZAREVICH Vanina LÓPEZ, Silvia E. FERREIRA, Adriana E. ROVERE, Patricia C. ESPINOZA, and Carolina R. SULBELZA. "Análisis granulométrico de sedimentos y dinámica fluvial en la cuenca del río Lorohuasi (Cafayate, Salta) / Granulometric analysis of sediments and fluvial dynamics in the Lorohuasi river basin (Cafayate, Salta)." Serie Correlación Geológica 37, no. 1 (2021): 19–48. https://doi.org/10.5281/zenodo.5512197.
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<strong>Resumen: </strong>Los procesos fluviales tienen la capacidad de modificar todos los sistemas terrestres. La liberación de componentes, su transporte y depositación como sedimentos por el agua, tienen consecuencias ambientales importantes, muchas de las cuales pueden ser deteriorantes o irreversibles. Las regiones áridas son susceptibles a la erosión hídrica, ya que la sola existencia de flujo ácueo es excepcional y la situación común es su extrema velocidad, que se conjuga con la variabilidad espacio-temporal del transporte de sedimentos. En este contexto, el objetivo fue analizar la dinámica en el transporte de sedimentos en la cuenca del río Lorohuasi, Cafayate, Salta, en los tramos medio de los tributarios Alisal y Colorado, en todo el río Lorohuasi y el sector de desembocadura con el río Santa María, entre los años 2016 y 2020. En 30 parcelas de 1 m<sup>2</sup> ubicadas en 14 sitios de estudios, se recolectaron 30 muestras de sedimentos medianos y finos en el cauce activo de los ríos. En cada sitio se midió el ancho y pendiente del cauce, como así también el caudal; con los datos granulométricos de los sedimentos medianos se construyeron gráficos de frecuencia acumulada y tablas de parámetros estadísticos (media, mediana, moda, desviación estándar, asimetría y curtosis), a fin de caracterizar y analizar la distribución de las fracciones granulométricas a lo largo de los cursos fluviales, evaluar la dinámica de sedimentación y caracterizar el agente de transporte. Los resultados exponen que en general, la granulometría media de todo el material analizado transportado en la cuenca del río Lorohuasi es arena media (phi 1,15), con media-mediana-moda en la misma fracción, la distribución es mesocúrtica, simétrica y el material es pobremente seleccionado. El sedimento se transporta mayormente por saltación en los ríos Colorado y Alisal, y por saltación y/o suspensión en el río Lorohuasi. Se concluye que las características físicas de la cuenca y las actividades antrópicas influyen en la granulometría de los sedimentos analizados, especialmente en la cuenca baja, y que técnicas de rehabilitación en las riberas afectadas podrían devolver la funcionalidad de las mismas y proteger el sistema fluvial. <strong>Abstract: </strong>River processes have the ability to modify all terrestrial systems. The release of components, their transport and deposition as sediments, by water have important environmental consequences, many of which can be deteriorating or irreversible. Arid regions are susceptible to water erosion, since the mere existence of water flow is exceptional and the common situation is its extreme speed, which is combined with the spatio-temporal variability of sediment transport. In this context, the objective was to analyze the dynamics of sediment transport in the Lorohuasi river basin, Cafayate, Salta, in the middle sections of the Alisal and Colorado tributaries, throughout the Lorohuasi river and the river mouth in the Santa María river, between the years 2016 and 2020. In 30 plots of 1 m<sup>2</sup> located in 14 study sites, 30 samples of medium and fine sediments were collected in the active channel of the rivers. At each site, the width and slope of the channel was measured, as well as the flow, with the granulometric data of the medium sediments, were constructed accumulated frequency graphs and tables of statistical parameters (mean, median, mode, standard deviation, asymmetry and kurtosis), in order to characterize and analyze the distribution of the granulometric fractions along the river courses, evaluate the sedimentation dynamics and characterize the transport agent. The results show that in general lines, the mean granulometry of all the analyzed material transported in the Lorohuasi river basin is mean sand (phi 1.15), with mean-median-mode in the same fraction, the distribution is mesokurtic, symmetric and the material is poorly selected. The sediment is transported majorly by saltation in the Colorado and Alisal rivers, and by saltation and/or suspension in the Lorohuasi river. It is concluded that the physical characteristics of the basin and anthropic activities influence the granulometry of the analyzed sediments, especially in the lower basin, and that rehabilitation techniques in affected riverbank areas could restore their functionality and protect the river system.
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Meyer, Patricia A., and Carolyn H. Eyles. "Nature and origin of sediments infilling poorly defined buried bedrock valleys adjacent to the Niagara Escarpment, southern Ontario, Canada." Canadian Journal of Earth Sciences 44, no. 1 (2007): 89–105. http://dx.doi.org/10.1139/e06-085.
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The buried Paleozoic bedrock surface of southern Ontario is dissected by an interconnected system of valleys. These buried valleys are infilled with thick successions of glacial, interglacial, and fluvial sediments that contain a lengthy record of changing environmental conditions during the late Quaternary. Detailed logging of over 500 m of sediment recovered from 11 continuously cored boreholes provides the basis for this study. The boreholes were drilled within two poorly defined bedrock valleys located east of the Niagara Escarpment in southern Ontario as part of a groundwater exploration program. Six distinct facies types were identified within the cores: sand, gravel, fine-grained sediment, and sand-rich, mud-rich, and clast-rich diamict. Textural characteristics of the cored sediments and vertical changes in facies types were used to identify six stratigraphic units (SU I through SU VI) within the valley-infill deposits. These units are interpreted to record fluvial or colluvial (SU I), lacustrine (SU II), fluvial, glaciofluvial or deltaic (SU III), subglacial (SU IV), glaciofluvial (SU V) and subglacial or ice marginal (SU VI) conditions. Sediment characteristics and stratigraphic relationships allow tentative correlation with known surficial deposits. Analysis of the subsurface characteristics and geometries of this stacked succession of coarse- and fine-grained stratigraphic units also allows identification of the geometry of potential aquifers.
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Miura, Hideki, Kiichi Moriwaki, Hideaki Maemoku, and Kazuomi Hirakawa. "Fluctuations of the East Antarctic ice-sheet margin since the last glaciation from the stratigraphy of raised beach deposits along the Sôya Coast." Annals of Glaciology 27 (1998): 297–301. http://dx.doi.org/10.3189/1998aog27-1-297-301.
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The fluctuation of the East Antarctic ice-shect (EAIS) margin and relative sea-level change since the last glaciation are discussed from the stratigraphy and TAMS 14C ages of raised beach deposits in the northern part of the Soya Coast.The beach deposits reveal two marine sediment layers with in situ fossil shells of Laternula elliptica, and an interbedded fluvial sediment layer. The l4C ages of fossils in the lower, older marine beds ranged from 36 to 43 ka, and in the upper, younger beds from 4.9 to 5.2 ka without reservoir correction. Neither marine layers nor in situ fossil shells were disturbed by ice-sheet loading or scouring. The interbedded fluvial sediments appear to have been deposited by a stronger fluvial process than present meltwater activity in the area. These facts lead us to the following conclusions: (1) marine transgression occurred during the last interstadial around 40 ka or the Last Intcrglacial, and in the Holocene around 5 ka: (2) the EATS possibly retreated from the northern Sôya Coast prior to the Last Glaciol Maximum (LGM); (3) the fluvial process may have occurred during a period of low sea level which may have been a warmer period than the present, probably during the late-Glaciol to postglaciol age; and (4) the EAIS did not rcadvance over these sediments during or since the LGM.
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Kirk, M. "Westphalian alluvial plain sedimentation, Isle of Arran, Scotland." Geological Magazine 126, no. 4 (1989): 407–21. http://dx.doi.org/10.1017/s0016756800006592.
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AbstractFacies analysis suggests that Westphalian (Upper Carboniferous) Coal Measure sequences on the Isle of Arran, Scotland, were deposited in a proximal alluvial plain environment close to the basin margin. Detailed examination of well exposed coastal sections has revealed the existence of six laterally and vertically interrelated sedimentary facies. Facies 1 to 3 are interpreted as fluvial channel deposits. Low sinuosity multistorey (facies 1), low sinuosity vertically accreted (facies 2), and rare high sinuosity laterally accreted channel deposits (facies 3) are developed. Associated overbank sediments comprise the deposits of crevasse splays (facies 4), flood plains (facies 5) and shallow lakes (facies 6). In terms of the spatial distribution of facies, a relatively high proportion of fluvial channel and floodplain deposits (facies 2 and 5) occur in the more proximal sequence at Laggan compared with the more distally located sequence occurring at Corrie. Palaeocurrent measurements from fluvial channel sandstones indicate that sediment source areas and the Westphalian basin margin lay to the north and northwest. Down palaeoslope towards the southeast, normal coal-bearing Westphalian sediments formed penecontemporaneously on the Scottish mainland in Ayrshire.A sedimentological model is presented for the proximal non-coal-bearing Westphalian sequences of Arran. This model can explain the differences observed between the Arran sediments, and contemporaneous normal coal-bearing Westphalian sediments of the Scottish mainland.
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Carranza-Edwards, Arturo, Leticia Rosales-Hoz, and Susana Santiago-Pérez. "Provenance memories and maturity of holocene sands in northwest Mexico." Canadian Journal of Earth Sciences 31, no. 10 (1994): 1550–56. http://dx.doi.org/10.1139/e94-137.
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Beach and fluvial sediments from the region around Todos Santos Bay, Baja California, have been studied to determine their maturity, provenance, chemical alteration, and tectonic relationships. Analysis of the CaO–Na2O–K2O content of several samples demonstrated a difference between those from a beach environment and those from a fluvial environment. Transport affects the characteristics of the sediment, producing an enrichment of material resistant to chemical and physical attack on the beach area. The beach sand samples are mineralogically and chemically more mature than those from the fluvial sands. The provenance index (feldspar/rock fragments) gives relatively low average values for fluvial sands, provided that they are richer in rock fragments. The chemical index of alteration has low average values for beach sands because the minerals are more resistant to energy from waves and currents. Tectonic settings, defined through the binary diagram from Roser and Korsch, suggest that the samples belong to active continental margin and arc domains. When tectonic fields are assigned, based on a Q–F–L triangular diagram analysis, the sediments from the study area fall in an active magmatic arc field, even though this region is not presently subject to subduction.
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Martínez-Mena, María, María Almagro, Noelia García-Franco, Joris de Vente, Eloisa García, and Carolina Boix-Fayos. "Fluvial sedimentary deposits as carbon sinks: organic carbon pools and stabilization mechanisms across a Mediterranean catchment." Biogeosciences 16, no. 5 (2019): 1035–51. http://dx.doi.org/10.5194/bg-16-1035-2019.
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Abstract. The role of fluvial sedimentary areas as organic carbon sinks remains largely unquantified. Little is known about mechanisms of organic carbon (OC) stabilization in alluvial sediments in semiarid and subhumid catchments where those mechanisms are quite complex because sediments are often redistributed and exposed to a range of environmental conditions in intermittent and perennial fluvial courses within the same catchment. The main goal of this study was to evaluate the contribution of transport and depositional areas as sources or sinks of CO2 at the catchment scale. We used physical and chemical organic matter fractionation techniques and basal respiration rates in samples representative of the three phases of the erosion process within the catchment: (i) detachment, representing the main sediment sources from forests and agricultural upland soils, as well as fluvial lateral banks; (ii) transport, representing suspended load and bedload in the main channel; and (iii) depositional areas along the channel, downstream in alluvial wedges, and in the reservoir at the outlet of the catchment, representative of medium- and long-term residence deposits, respectively. Our results show that most of the sediments transported and deposited downstream come from agricultural upland soils and fluvial lateral bank sources, where the physicochemical protection of OC is much lower than that of the forest soils, which are less sensitive to erosion. The protection of OC in forest soils and alluvial wedges (medium-term depositional areas) was mainly driven by physical protection (OC within aggregates), while chemical protection of OC (OC adhesion to soil mineral particles) was observed in the fluvial lateral banks. However, in the remaining sediment sources, in sediments during transport, and after deposition in the reservoir (long-term deposit), both mechanisms are equally relevant. Mineralization of the most labile OC (the intra-aggregate particulate organic matter (Mpom) was predominant during transport. Aggregate formation and OC accumulation, mainly associated with macroaggregates and occluded microaggregates within macroaggregates, were predominant in the upper layer of depositional areas. However, OC was highly protected and stabilized at the deeper layers, mainly in the long-term deposits (reservoir), being even more protected than the OC from the most eroding sources (agricultural soils and fluvial lateral banks). Altogether our results show that both medium- and long-term depositional areas can play an important role in erosive areas within catchments, compensating for OC losses from the eroded sources and functioning as C sinks.
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Khan, A. A., and A. Sonakia. "Quaternary Deposits of Narmada with Special Reference to the Hominid Fossils." Journal Geological Society of India 39, no. 2 (1992): 147–54. http://dx.doi.org/10.17491/jgsi/1992/390206.
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Abstract The upper 70 m to 90 m of the Narmada alluvium was deposited in a single aggradational episode with minor pauses when dissection of the alluvium produced two terraces (NT3-NT2). The sediments of this aggradation episode constitute three lithostratigraphic units viz., Boulder conglomerate, Sohagpur and Shahganj Fomations. The sediments of the alluvial phase are underlain by a boulder bed of glacio-fluvial origin. Thus, the fossiliferous boulder conglomerate, the basal unit of the alluvium marks a disconformity between the lower glacio-fluvial boulder layer and the upper fluvial sediments. The fossiliferous basal boulder conglomerate is considered to be of middle Pleistocene age.
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Porzionato, Natalia, Mariangeles Mellota, Roberto Candal, and Gustavo Curutchet. "Acid Drainage and Metal Bioleaching by Redox Potencial Changes in Heavy Polluted Fluvial Sediments." Advanced Materials Research 825 (October 2013): 496–99. http://dx.doi.org/10.4028/www.scientific.net/amr.825.496.
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Sediments from polluted urban streams act as a sink of contaminants. The high content of organic matter and sulphides makes the system appropriate for binding heavy metals. However, changes in the redox potential leads to processes in which sediments acts like a low sulphidic ore in an oxidizing environment, and could generate acid drainages. Human and not human disturbances of the sediments could derive in its oxidation catalyzed by sulphur oxidizing bacteria (SOB). This process leads to acidification and metal release. In this study we analyze the acidification potential of anaerobic sediments of polluted streams near Buenos Aires with static and kinetic methods. The results remark the necessity to consider this process before any sediment management action.
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Bartyik, Tamás, Cristian Floca, Elemér Pál-Molnár, Petru Urdea, Diaa Elsayed Hamed, and György Sipos. "The Potential Use of Osl Properties of Quartz in Investigating Fluvial Processes on the Catchment of River Mureş, Romania." Journal of Environmental Geography 14, no. 1-2 (2021): 58–67. http://dx.doi.org/10.2478/jengeo-2021-0006.
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Abstract To understand the functioning of fluvial systems it is important to investigate dynamics of sediment transport and the source of sediments. In case of reconstructing past processes these studies must be accompanied by the numerical dating of sediment samples. In this respect optically stimulated luminescence is a widely used technique, by which the time of sediment deposition can be directly dated. Recently, in various fluvial environments it has been shown that certain luminescence properties of minerals, and especially that of quartz, can be applied as indicators of fluvial erosion and/or sediment provenance. These properties are residual luminescence (or residual dose) and luminescence sensitivity of quartz grains. However, the values of the parameters above are affected by various factors, the importance of which is under debate. The present study therefore aims to assess these factors along a ~560 km long reach of River Mureş (Maros) a relatively large river with a compound surface lithology on its catchment. The research focused on the sandy fraction of modern sediments, collected from the main river and from three tributaries alike. This way not only longitudinal downstream changes, but the influence of tributaries could also be studied. Based on the data, both investigated parameters show a great variation, which can be attributed to the lithological differences of subcatchments and geomorphological drivers, such as erosional activity and potential number of sedimentary cycles, and human activity. However, relationships are not entirely clear and are influenced by the maximum grain size of the samples investigated, and the recycling of previously laid deposits with different properties. Still, when performing detailed dating studies, and tracing sediments from certain parts of the catchment luminescence properties can be a useful tool in the future.
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Gailleton, Boris, Luca C. Malatesta, Guillaume Cordonnier, and Jean Braun. "CHONK 1.0: landscape evolution framework: cellular automata meets graph theory." Geoscientific Model Development 17, no. 1 (2024): 71–90. http://dx.doi.org/10.5194/gmd-17-71-2024.
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Abstract. Landscape evolution models (LEMs) are prime tools for simulating the evolution of source-to-sink systems through ranges of spatial and temporal scales. A plethora of various empirical laws have been successfully applied to describe the different parts of these systems: fluvial erosion, sediment transport and deposition, hillslope diffusion, or hydrology. Numerical frameworks exist to facilitate the combination of different subsets of laws, mostly by superposing grids of fluxes calculated independently. However, the exercise becomes increasingly challenging when the different laws are inter-connected: for example when a lake breaks the upstream–downstream continuum in the amount of sediment and water it receives and transmits; or when erosional efficiency depends on the lithological composition of the sediment flux. In this contribution, we present a method mixing the advantages of cellular automata and graph theory to address such cases. We demonstrate how the former ensure interoperability of the different fluxes (e.g. water, fluvial sediments, hillslope sediments) independently of the process law implemented in the model, while the latter offers a wide range of tools to process numerical landscapes, including landscapes with closed basins. We provide three scenarios largely benefiting from our method: (i) one where lake systems are primary controls on landscape evolution, (ii) one where sediment provenance is closely monitored through the stratigraphy and (iii) one where heterogeneous provenance influences fluvial incision dynamically. We finally outline the way forward to make this method more generic and flexible.
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Liu, Shih-Hung, Robert Hebenstreit, and Margot Böse. "Late Quaternary landform evolution and sedimentary successions in the Miaoli Tableland, northwestern Taiwan." E&G Quaternary Science Journal 71, no. 1 (2022): 1–22. http://dx.doi.org/10.5194/egqsj-71-1-2022.
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Abstract. Elevated Quaternary sedimentary complexes in the western foreland of the central mountain ranges of Taiwan are called tablelands. Their mostly flat surfaces are deeply incised by fluvial processes. The landforms and the fluvial systems in the Miaoli Tableland are investigated by high-resolution terrain analyses based on different datasets. Sediments are described in 51 outcrops and characterized by grain size composition. The outcrops revealed complete or incomplete sequences of the general scheme from bottom to top: sandy tidal–coastal units overlain by gravel- and cobble-rich fluvial deposits always with a fine-grained silt-rich top cover layer influenced by aeolian deposits. All layers are unconsolidated sediments. Three subtypes of this sequence were identified, with respect to the occurrence of the fluvial deposits. The relation of tectonic and erosional processes including the rework of gravels is discussed. The results reveal a tableland surface much more disaggregated than previously mapped, suggesting that individual tableland segments represent remnants of an inferred palaeotopography. The tableland surfaces have been separated into Sedimentary Highlands (SH-I and SH-II) and Sedimentary Terraces (ST) by geometrical properties. The Alluvial and Coastal Plains (AL) represent broad valley bottoms (“box-shaped valleys”) in the dendritic drainage systems below 150 m and the coastal plains. The landforms and predominantly the sediment sequences are discussed in the context of the existing stratigraphical schemes of the Toukoshan Formation and the so far rarely used Lungkang Formation. The latter is recommended as the stratigraphical term for the refined subdivision of the uppermost part of late Quaternary sediments in the Miaoli Tableland.
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Balatka, Břetislav, and Jaroslava Loučková. "Quaternary Terraces of the Berounka River." Geografie 96, no. 3 (1991): 145–62. http://dx.doi.org/10.37040/geografie1991096030145.
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The paper brings geomorphological characteristic of Neogene sediments and Pleistocene terraces of the Berounka (the left tributary to the Vltava). The localities of Neogene fluvial and fluvial-lacustrine sediments of Lower Miocene Age are clean-cut and neotectonically dislocated. The Pleistocene terraces (13 levels in 7 groups), diverging downstream, have been incorporated into the stratigraphical Pleistocene system.
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A, Rabiu, and Maigari A S. "Flow velocity and implication on particle size of bottom sediment in the commodore channel lagos, southwestern nigeria." Global Journal of Pure and Applied Sciences 29, no. 1 (2023): 19–27. http://dx.doi.org/10.4314/gjpas.v29i1.3.
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Flow velocity generally influences the erosion, transport and deposition of sediments. Flow velocity and in relation to particle size distribution in the Commodore channel was investigated with the Acoustic doppler current profiler (ADCP), echosounder and veen van grab. Those equipment were deployed through a low draft survey boat to acquire acoustic and sediment data covering the study area. The ADCP measured the current velocity along fourteen established transect lines while twenty surface sediments samples were collected along the banks and center of the channel respectively. Sediment samples were analyzed for grain size distributions and mineralogicaly composition while the acoustics data were analyzed with Matlab software to produce velocity profiles for the channel area. The study aimed to determine the magnitude and direction of flow of water along the channel with a view to ascertain the sediment transport process. Results indicated no significant difference in flow velocities along the different channel points. The flow velocity was however slightly higher around the channel mouth than in mid and upper reaches of the channel. The flow velocities showed negative correlation of (– 0.54 and – 0.28) with the sediment characteristics indicating that the sediment particle size distributions is unrelated to the flow velocity. This anomaly in the equilibrium flow velocity suggest the impact of dredging and the continuous ebbing and flooding of tidal water which resulted to reworking of the sediment particle sizes prior to deposition. The sediment distributions were fine sand, moderately sorted, fine skewed with leptokurtic peaked. Significant fractions of the sediments were deposited in fluvial and shallow marine environments while a few were deposited in the beach and turbidity environment. Sediments and acoustic data interpreted from the study suggest that sediment supply to the area was by fluvial processes through the barrier lagoon drainage basin.
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Droppo, Ian G. "Biofilm structure and bed stability of five contrasting freshwater sediments." Marine and Freshwater Research 60, no. 7 (2009): 690. http://dx.doi.org/10.1071/mf08019.
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Using an annular flume, erosion characteristics of five diverse sediment types (stormwater pond, contaminated lacustrine, fluvial, aquaculture waste and industrial grade kaolin sediment), each with different physical and biological characteristics, were examined for relative erosion resistance and factors contributing to bed sediment stability. Suspended flocs represent primary building blocks of bed sediment with mass settling being independent of suspended solid concentration. Biofilm growth period, depositing floc structure and composition, nutrient supply and sediment properties all played a complex role in dictating the stability of the sediments. The river, lake and stormwater pond sediments were the most resistant to erosion relative to the high nutrient and organic content aquaculture sediment and kaolin. Biofilms developed to varying degrees on all sediments with the greatest growth occurring with the aquaculture sediment and the least with kaolin. While electrochemical properties will provide some attraction and stabilising forces, with no measurable consolidation evident for the examined sediments, it is suggested that active biofilm development was the dominant factor controlling bed stability and erosion potential. Differences in biological mediation of strength between sediments were partially attributed to the structural differences within the biofilms and integration of the extracellular polymeric fibril matrix within the sediment pores.
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Lake, Randal G., and Scott G. Hinch. "Acute effects of suspended sediment angularity on juvenile coho salmon (Oncorhynchus kisutch)." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 5 (1999): 862–67. http://dx.doi.org/10.1139/f99-024.
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To determine the roles of suspended sediment angularity and concentration as contributors to stress and mortality in salmonids, we exposed juvenile coho salmon (Oncorhynchus kisutch) to anthropogenically derived "extremely angular" and "round" silicate sediments over a range of concentrations in 96-h experiments. Stress responses (e.g., decreased leukocrit) were elicited by exposure to both sediment shapes when concentrations were >40 g·L-1, corresponding to the minimum concentration at which physical gill damage was observed. Extremely angular sediments also caused stress responses (e.g., elevated hematocrit, decreased leukocrit) at concentrations <41 g·L-1. However, we found no difference between sediment shapes in causing mortality at any sediment concentration. Further, mortalities were not observed until concentrations were about 100 g·L-1, a value that is about an order of magnitude greater than high natural concentrations in salmonid rivers. Natural fluvial suspended sediments cause fish stress and mortality at much lower concentrations than we found with our anthropogenically derived suspended sediments.
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Ryder, June M., and Michael Church. "The Lillooet terraces of Fraser River: a palaeoenvironmental enquiry." Canadian Journal of Earth Sciences 23, no. 6 (1986): 869–84. http://dx.doi.org/10.1139/e86-089.
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The history of Holocene fluvial terraces was investigated by stratigraphic, morphological, and palaeohydrologic methods. The terraces were formed in glaciofluvial and glaciolacustrine sediments by the Fraser River: degradation alternated with episodes of stability and aggradation. The uppermost terraces, four nonpaired surfaces, were occupied by a braided river. Vertical stability was controlled either by the water and sediment discharge of the river or by backwater effects from downstream landslides. The lower terraces, two paired surfaces, and associated fluvial sediments provide evidence for at least two cycles of aggradation and downcutting. These can be attributed to the effects of landslides that occurred a short distance downstream. Climatic variations may also have influenced terrace formation, but direct evidence is lacking. Palaeohydraulic investigations based on gravel texture, terrace gradients, and geometry of palaeochannels provide results that although approximate, conform with conclusions based upon terrace morphology and stratigraphy.
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Armstrong, Shalamar, Douglas Smith, Phillip Owens, et al. "Phosphorus and nitrogen loading depths in fluvial sediments following manure spill simulations." Canadian Journal of Soil Science 91, no. 3 (2011): 427–36. http://dx.doi.org/10.4141/cjss10003.
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Armstrong, S. D., Smith, D. R., Owens, P. R., Joern, B. C., Leytem, A. B., Huang, C.H. and Adeola, L. 2011. Phosphorus and nitrogen loading depth in fluvial sediments following manure spill simulations. Can. J. Soil Sci. 91: 427–436. The depth of nitrogen (N) and phosphorus (P) loading in fluvial sediments following a manure spill has not been documented. Thus, the objectives of this study were: (i) to determine the depth of N and P enrichment as a result of a manure spill under base flow conditions using fluvarium techniques and (ii) to evaluate the impact of sediment particle size distribution on N and P enrichment depth. Manure spills were simulated using stream simulators and ditch sediments collected from agricultural drainage ditches. During the manure spill simulation, the P sorption capacity of all sediments exponentially decreased with time and the NH4-N sorption capacity remained constant with time. The P and NH4-N loading in all sediments were observed to the depth of 2 cm, but were most concentrated in the 0- to 1-cm depth ranging in concentrations from 3 to 12 mg P kg−1 and from 7.2 to 45 mg NH4-N kg−1. Data from this study give a basis for the advancement of manure spill remediation that will reduce the impairment of surface waters via the release of nutrients from enriched sediments following a manure spill.