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Thoroughly investigating the evolution of groundwater circulation and its controlling mechanism in the Aksu River Basin, where human activities are intensifying and the groundwater environment is increasingly deteriorating, is highly urgent and important for promoting the theory, development and implementation of groundwater flow systems (GFSs) and protecting groundwater resources. Based on a detailed analysis of the sediment grain size distribution, chronology, electrofacies, glacial sedimentary sequence, palaeoclimate indicators and existing groundwater age, this paper systematically reconstructs the palaeosedimentary environment of the basin-scale aquifer system in the study area and scientifically reveals the evolutionary pattern and formation mechanism of the GFS. The results showed that the later period of the late Pleistocene experienced a rapid downcutting erosional event caused by tectonic uplift, and the sedimentary environment transitioned from a dry–cold deep downcutting environment in the Last Glacial Maximum (LGM) to a coarse-grained fast-filling fluvial facies sedimentary environment in the Last Glacial Deglaciation (LDP) as the temperature rose; then, it shifted to an environment of fine-grained stable alternating accumulation of fluvial facies and lacustrine facies that was dominated by the warm and arid conditions of the Holocene megathermal period (HMP); this process changed the previous river base level via erosion, glacier elongation or shortening and river level, thus resulting in a complex coupling relationship between the palaeosedimentary environment, palaeoclimate and basin GFS. Furthermore, the existing GFS pattern in the basin exhibits a vertically unconformable groundwater age distribution, which indicates that it is the outcome of the complex superposition of groundwater flow controlled by the palaeosedimentary environment in different periods. Therefore, neotectonic movement and climate fluctuation have jointly acted on the variation in the river level, resulting in the "seesaw" effect, thereby fundamentally controlling the strength of the driving force of groundwater and resulting in the gradual evolution of the GFS from the fully developed regional GFS pattern during the LGM to the current multihierarchy nested GFS pattern. [ABSTRACT FROM AUTHOR]

Despite extensive research on alluvial architecture, there is still a pressing need for data from modern fluvio-deltaic environments. Previous research in the fluvial-dominated proximal and central Rhine–Meuse delta (the Netherlands) has yielded clear spatial trends in alluvial architecture. In this paper, we include the backwater length to establish architectural trends from apex to shoreline. Channel-belt sand body width / thickness ratios and interconnectedness were determined, and the proportions of fluvial channel-belt deposits, fluvial overbank deposits, organics and intertidal deposits were calculated for the complete fluvio-deltaic wedge based on high-resolution geological cross sections. It was found that the average width / thickness ratio of channel-belt sand bodies in the proximal delta is 5 times higher than in the distal delta. Other down-valley trends include an 80 % decrease in the channel deposit proportion (CDP) and a near-constant proportion of overbank deposits. Additionally, interconnectedness in the proximal delta is 3 times higher than in the distal delta. Based on the Rhine–Meuse dataset, we propose a linear empirical function to model the spatial variability of CDP. It is argued that this relationship is driven by four key factors: channel lateral-migration rate, channel-belt longevity, creation of accommodation space and inherited floodplain width. Additionally, it is established that the sensitivity of CDP to changes in the ratio between channel-belt sand body width and floodplain width (normalized channel-belt sand body width) varies spatially and is greatest in the central and distal delta. Furthermore, the proportion of fluvial channel-belt sands is generally an appropriate proxy for the total sand content of fluvio-deltaic successions, although its suitability as a total sand indicator rapidly fades in the distal delta. Characteristics of the backwater zone of the Rhine–Meuse delta are (1) sand body width / thickness ratios that are lower as a consequence of channel narrowing (not deepening), (2) a rapid increase and then a drop in the organic proportion, (3) an increase in the total sand proportion towards the shoreline, and (4) a drop in the connectedness ratio. For this paper, unique high-resolution quantitative data and spatial trends of the alluvial architecture are presented for an entire delta, providing data that can be used to further improve existing fluvial stratigraphy models. [ABSTRACT FROM AUTHOR]

The Jizera River in Czechia is a typical mid‐sized Central European watercourse. Its floodplain shows a morphological contrast between the laterally stable low‐sinuous current channel and preserved palaeomeanders. The aim of this paper was to date and explain the obvious metamorphosis of the channel pattern from meandering to low‐sinuous. We analysed the morphology of the lower river reach using a digital terrain model (DTM) and historical maps from the 1840s. Furthermore, the floodplain architecture was described based on the DTM, geophysical imaging (ground penetrating radar, GPR), sediment lithology and anthropogenic contamination using geochemical proxies, and optically stimulated luminescence (OSL) dating. The geochemical proxies were processed using log‐ratio methods from the compositional data analysis toolbox. According to our results the Jizera River showed signs of systematic lateral floodplain reworking during the Late Holocene with only minor aggradation, although parts of the catchment are covered by easily erodible loess. Interestingly, vertical aggradation did not show a significant increase during the last millennium. In the main study area, this limited vertical aggradation resulted in the preservation of palaeomeander fragments and palaeochannel belts with 100–200 m mean width in the 300–600 m wide floodplain, which are recognisable in the topography and in subsurface GPR imaging. This channel meandering took place between around 4 and 1.2 ka, and the transition towards the laterally stable modern channel with low sinuosity occurred around 1.2 ka. This timing indicates a climatic rather than anthropogenic impact, which was rather weak around that time. One likely cause for this transition was the influx of material from ravines incised into the sandstone valley edges during past climatic extremes. Subsequently, the re‐establishment of a meandering pattern was possibly prevented by a combination of low fluvial activity and the construction of weirs that reduced stream power. [ABSTRACT FROM AUTHOR]

Dryland fluvial systems respond to hydroclimate changes on Quaternary timescales, yet deciphering the palaeoenvironmental histories they preserve is often complex. Whilst hydrological signals are preserved in sediment stores as variations in sediment amount, character, and composition, studies in dryland settings such as Namibia that link sedimentological and compositional changes to palaeoflow are limited. Focusing on the Huab River, Skeleton Coast, this paper presents the first integrated study of textural, compositional, and stratigraphic features from a Namibian fluvial archive. Petrographic and heavy mineral assemblages from Raman laser spectroscopy are combined with lithostratigraphic and particle size analysis. Together with a chronology established through 42 optically stimulated luminescence ages, we reconstruct provenance, changes in river style, and fluvial response to climate. The Huab lithostratigraphic record details periods of flashy ephemeral flow interbedded with flow within well‐defined channels. Compositional assemblages indicate that humid conditions during the early to mid‐Holocene resulted in activation of sediment stores across the catchment. Episodic discharge within an ephemeral river from 12 to 9 ka was followed by a more sustained river flow in a channelized system from 7 to 5 ka. During the late Holocene, better hydraulic sorting, increased mechanical breakdown of polycrystalline grains, and flash flood lithofacies suggest that flow occurred within a more arid climate. This fine‐scaled analysis of an ephemeral fluvial system indicates the utility of assessing compositional changes to distinguish between depositional regimes. This is an important approach for reconstructing fluvial response to climate and for obtaining palaeoenvironmental records from complex sedimentary archives in dryland river settings. [ABSTRACT FROM AUTHOR]

Lakes act as important sinks for inorganic and organic sediment components. However, investigations of sedimentary carbon budgets within glacial lakes are currently absent from Arctic Siberia. The aim of this paper is to provide the first reconstruction of accumulation rates, sediment and carbon budgets from a lacustrine sediment core from Lake Rauchuagytgyn, Chukotka (Arctic Siberia). We combined multiple sediment biogeochemical and sedimentological parameters from a radiocarbon-dated 6.5 m sediment core with lake basin hydroacoustic data to derive sediment stratigraphy, sediment volumes and infill budgets. Our results distinguished three principal sediment and carbon accumulation regimes that could be identified across all measured environmental proxies including early Marine Isotope Stage 2 (MIS2) (ca. 29–23.4 ka cal BP), mid-MIS2–early MIS1 (ca. 23.4–11.69 ka cal BP) and the Holocene (ca. 11.69–present). Estimated organic carbon accumulation rates (OCARs) were higher within Holocene sediments (average 3.53 g OC m -2 a -1) than Pleistocene sediments (average 1.08 g OC m -2 a -1) and are similar to those calculated for boreal lakes from Quebec and Finland and Lake Baikal but significantly lower than Siberian thermokarst lakes and Alberta glacial lakes. Using a bootstrapping approach, we estimated the total organic carbon pool to be 0.26 ± 0.02 Mt and a total sediment pool of 25.7 ± 1.71 Mt within a hydroacoustically derived sediment volume of ca. 32 990 557 m 3. The total organic carbon pool is substantially smaller than Alaskan yedoma, thermokarst lake sediments and Alberta glacial lakes but shares similarities with Finnish boreal lakes. Temporal variability in sediment and carbon accumulation dynamics at Lake Rauchuagytgyn is controlled predominantly by palaeoclimate variation that regulates lake ice-cover dynamics and catchment glacial, fluvial and permafrost processes through time. These processes, in turn, affect catchment and within-lake primary productivity as well as catchment soil development. Spatial differences compared to other lake systems at a trans-regional scale likely relate to the high-latitude, mountainous location of Lake Rauchuagytgyn. [ABSTRACT FROM AUTHOR]

For decades, it has been unclear as to how the world's first cities, in southern Mesopotamia, not only arose in a fluvial environment but also how this environment changed. This paper seeks to understand the long-term fluvial history of the region around Uruk, a major early city, in relation to water-human interactions. This paper applies geomorphological, historical and archaeological approaches and reveals that the Uruk region in southern Mesopotamia had been under the influence of freshwater fluvial environment since the early Holocene. It further demonstrates how canals and long-term human activities since the mid Holocene have been superimposed on the natural river channel patterns. Fieldwork has been conducted to ground-truth features identified applying remote sensing techniques. Five sediment cores were analysed to elucidate palaeoenvironmental changes. Radiocarbon ages for organic samples suggest that the oldest sediment layers, at a depth of 12.5 m, are from the Early Holocene, while results from diatom analyses imply that the whole sediment column was deposited in a freshwater environment. Intensive networks of palaeochannels and archaeological sites within the study area have been reconstructed and these networks have been divided into four different time intervals based on changes in channel courses. The first is from the early 4th to the late 1st millennium BCE; the second is from the late 1st millennium BCE to the middle 2nd millennium CE; the third lasted from after the Islamic period until the 1980s; the fourth is from the 1980s until the present. Key results include evidence for freshwater environments and favourable settlement conditions had already formed by the 8th millennium BCE. The favourable settlement environment resulted in stable (long-lived) canals between the 4th millennium BCE and 1st millennium CE. A significant settlement and irrigation expansion occurred in the early 1st millennium CE. Major abandonment ensued in the late 1st millennium CE and lasted until the mid 2nd millennium CE. [ABSTRACT FROM AUTHOR]

This paper presents new sedimentological, geomorphological, and optically stimulated luminescence (OSL) geochronological evidence for fluvial evolution of the mid- to lower River Tyne through the Lateglacial to late Holocene. These data reveal a series of fluvial terraces produced by cycles of aggradation and incision, conditioned by glacial inheritance and driven by changing sediment availability and hydrological regime. The distribution and stratigraphy (where available) of nine river terrace and their associated sediments have been recorded. At two key sites the sediments have been dated using OSL measurements to constrain the fluvial geomorphology. Significant entrenchment of the fluvial system, followed by aggradation formed the earliest fluvial terrace (T1), which encompasses environments spanning the transition from deglaciation into Greenland Interstadial 1 (GI-1). Incision below T1 began towards the end of GI-1, with three terraces (T2 – T4) between the abandonment of T1 and the early Holocene (15.0–9.2 ka). Climatic shifts, limited vegetation cover/soil development, and peri −/paraglacial landscape instability conditioned the development of the early postglacial fluvial landsystem. Three further terraces (T5 – T7) developed during the mid- to Late Holocene (6.6–3.1 ka), and comprise most of the valley floor. Climatic instability, glacial inheritance, and widespread anthropogenic disturbances are reflected in greater hillslope-channel coupling during this period. The extent of later Holocene terraces (T8 – T9) is limited as the river became isolated from flanking hillslopes entrenched between existing river terraces. Fluvial landscape evolution in formerly glaciated catchments is strongly conditioned by the cold stage legacy that introduced excess sediment and landscape instability into the catchment. Subsequent catchment-wide responses are variable and non-linear, with valley floors operating in a series of reach-wide responses. There is a need for greater chronological control to constrain the Lateglacial and Holocene evolution in the Tyne catchment, but also to further our understanding of region-wide responses to external drivers and local dynamics. • Lateglacial to late Holocene fluvial response recorded from river terrace sequence. • Fluvial landscape strongly conditioned by glacial legacy. • Catchment-wide responses are non-linear and valley floors operated as reach-wide responses. • River responded to climate and/or landscape perturbations at ∼16, 11.9, 8.7, 4 ka. [ABSTRACT FROM AUTHOR]

The Texas Creek rock avalanche is a prehistoric deposit in the Fraser River Canyon, 17 km south of Lillooet, southwestern British Columbia, Canada. Original mapping suggested that the debris consisted of two landslides: a 45 Mm3 event deposited after the Mazama tephra but before about 2 ka ago, and a 7.2 Mm3 event about 1.1 ka ago. The proposed timing of the younger landslide was correlated with a decline in the First Nations population and was proposed as an agent of cultural collapse driven by its impact on salmon returns vital to the population's sustenance. We provide six surface exposure ages using 10Be from boulder tops, with three samples from each surface that were originally posited to be older and younger debris. The six samples yielded similar ages suggesting the landslide deposit represents a single event with an average age of 2.28 ± 0.19 (2σ external error) ka before 1950 AD. Evidently, the landslide played no role in the cultural collapse. Fraser River Holocene incision rates, estimated pre- and post-landslide are between 13 and 24 mm/yr, consistent with previous estimates for the mid-Fraser River region. Landslide timing is coincident with the explosive eruption of Mount Meager, 120 km to the northwest, and with a possible landslide at Mystery Creek 85 km to the west and 65 km south of Mount Meager. The landslide may have been seismically triggered, but attribution is speculative. [ABSTRACT FROM AUTHOR]

Marine geological studies of Naples Bay are discussed and reviewed, focusing on the application of the seismo-stratigraphic concepts to a Late Quaternary volcanic area. The Naples Bay represents an active volcanic area in which the interactions between volcanic and sedimentary processes controlled a complex stratigraphic architecture during the Late Quaternary period. While the volcanic processes took place in correspondence with the activity of the Somma–Vesuvius, Campi Flegrei Ischia, and Procida volcanic complexes, the sedimentary processes were controlled by the fluvial processes in the Sarno-Sebeto coastal plain and by the tectonic uplift in correspondence with the Sorrento Peninsula's structural high Key geophysical and stratigraphic studies of the three active volcanic complexes are revised and discussed. The seismo-stratigraphic concepts applied in the geological interpretation of seismic profiles of Naples Bay are reviewed and discussed: here, the classical concepts of seismic and sequence stratigraphy have been successfully applied, but only partly, due to the occurrence of several buried volcanoes and volcanic seismic units and tephra layers, calibrated by gravity cores. [ABSTRACT FROM AUTHOR]

In the eastern United States, existing paleo-reconstructions in fluvial environments consist primarily of site-specific investigations of climate and human impacts on riverine processes. This paper presents the first meta-analysis of fluvial reconstructions focused on regional watersheds of the eastern United States, including the Lower Mississippi, Tennessee, South Atlantic–Gulf Coast, Ohio, Mid-Atlantic, and New England regional watersheds. Chronologies of fluvial activity (i.e. alluvial deposition) and stability (i.e. landscape stability) were developed by synthesizing data from existing, published, and site-specific fluvial reconstruction studies conducted across the eastern United States. Overall, regional watersheds show variable patterns of synchronicity across watersheds and did not demonstrate cyclic behavior through the Holocene. During the last millennium, only the Lower Mississippi and Ohio regional watersheds exhibit high rates of fluvial activity active during the 'Medieval Climate Anomaly' (650–1050 yr BP), while nearly all other regional watersheds in the eastern United States were active during the 'Little Ice Age' (100–500 yr BP). These findings imply that fluvial activity may be more spatially restricted during warmer/drier climatic conditions than during cooler/wetter periods. We find an increase in fluvial activity during the era of Euro-American colonization (400 yr BP to present) in the southeastern United States but not the northeastern United States, implying a heterogeneous response of fluvial systems to human activities in the eastern United States related to climatic, cultural, and/or physiographic variability. These new insights gained from fluvial chronologies in the eastern United States demonstrate the utility of regionally synthesized paleo-records to understand large-scale climate variation effect on rivers. [ABSTRACT FROM AUTHOR]

The Wei River catchment in the southern part of the Chinese Loess Plateau (CLP) is one of the centers of the agricultural revolution in China. The area has experienced intense land use changes since ∼6000 BCE, which makes it an ideal place to study the response of fluvial systems to past anthropogenic land cover change (ALCC). We apply a numerical landscape evolution model that combines the Landlab landscape evolution model with an evapotranspiration model to investigate the direct and indirect effects of ALCC on hydrological and morphological processes in the Wei River catchment since the mid-Holocene. The results show that ALCC has not only led to changes in discharge and sediment load in the catchment but also affected their sensitivity to climate change. When the proportion of agricultural land area exceeded 50 % (around 1000 BCE), the sensitivity of discharge and sediment yield to climate change increased abruptly indicating a regime change in the fluvial catchment. This was associated with a large sediment pulse in the lower reaches. The model simulation results also show a link between human settlement, ALCC and floodplain development: changes in agricultural land use led to downstream sediment accumulation and floodplain development, which in turn resulted in further spatial expansion of agriculture and human settlement. [ABSTRACT FROM AUTHOR]

To determine the post‐40 ka slip‐rate along the Mojave section of the San Andreas Fault (MSAF) we re‐analyze the sedimentary record preserved where Little Rock (LR) Creek flows across the fault. At this location, interaction between the northeast‐flowing stream and right‐lateral fault has resulted in the abandonment and preservation of 11 strath terraces and one paleo‐floodplain in the downstream trailing corner of the river, two of which are also preserved upstream to provide cross‐fault matches. A new model of fault‐induced river deflection, together with standard terrace riser restoration, yields strike‐slip displacements of 1,140 ± 160 m for the older terrace and 360 ± 70 m for the younger one. When combined with new 10Be dating and reinterpretation of prior measurements the displaced terraces yield right‐lateral slip‐rates of 27.7+6.9/−3.5 and 26.8+3.4/−3.0 mm/yr over the last 23 k.y. and last 40 k.y., where uncertainties are at 95% credible intervals. These new rate determinations are consistent with independent late Holocene estimates, indicating that the long‐term rate of strain accumulation along the MSAF is relatively fast and does not vary significantly when averaged over timescales of 15–20 k.y. Using our new model of stream deflection, we find that the fluvial sequence was emplaced in two distinct periods, each characterized by a temporally stable but markedly different deflected river geometry. Each period coincides with a distinct stage of erosive power along LR Creek determined from independent paleoclimate proxies. Importantly, application of the new river‐deflection model allows strike‐slip displacements to be determined in the absence of upstream piercing points. Key Points: Fluvial stratigraphy of Little Rock Creek is characterized from field mapping, lidar data analysis, and 10Be‐exposure datingA new model explains the formation of fluvial terraces within the downstream trailing corner along a strike‐slip deflected riverTwo new offset‐age pairs yield an average slip rate of ∼27 mm/yr over the last 23−40 k.y. for the Mojave section of the San Andreas Fault [ABSTRACT FROM AUTHOR]

Proglacial settings in the Alps are typically polygenetic, often characterized by a complex and discontinuous interplay between glacial, fluvial, and gravitational processes. These processes yield high volume of sediments, which usually exceeds the transportation capacity. The excessive proglacial sediment load leads to accumulation on slopes, and thus, to subsequent failures such as debris flows. Such failures can occur unexpectedly and harm the villages and infrastructure in the vicinity of proglacial environments. The northern slopes of the Ferret and Veny valleys in the Mont Blanc Massif are home to several polygenetic cones and are a stunning field laboratory for the exploration of the interplay between the glacial, fluvial, and gravitational processes. This study investigates one of the active and well-preserved polygenetic cones in these valleys, namely the Frébouge cone, to disentangle the geomorphic processes that contributed to its formation, and to reconstruct its evolution. To achieve these goals, detailed field, and remote mapping, 10Be surface exposure dating of different geomorphic features, and runout modelling with DAN3D® were applied. The geomorphological map revealed complex interactions of glacial, fluvial, debris flow, and rock and snow avalanche processes. The established chronology indicates two major fluxes of debris flows, the first one at ca. 2 ka, and the second at ca. 1 ka. In addition, a rock mass with a maximum volume of to 12 Mm3 collapsed in the upper reaches of the cone at 1.3 ± 0.1 ka and overran the cone, travelling more than 100 m up onto the opposite valley slope. Afterwards, the Frébouge Glacier overrode the cone several times leaving moraines and till, reaching its maximum extent ca. 300 years ago. This study underscores the untwisting of the complex interaction of surface processes in the Alpine valleys, which are prone to hit the urban areas and infrastructure. [ABSTRACT FROM AUTHOR]

The fluvial geomorphology and stratigraphy on the middle Snake River at Bancroft Springs, Idaho, provide evidence for numerous episodes of Snake River aggradation and incision since the Bonneville Flood at ca. 18 ka. A suite of seven terraces ranging from 20–1 m above modern bankfull elevation records multiple cut-and-fill cycles during the latest Pleistocene and Holocene in response to local base-level controls, variations in sediment supply, and hydroclimate change. Radiocarbon and luminescence dating show that the ages of fluvial aggradation generally coincide with increased sediment supply and likely wetter hydroclimate during onset of the Younger Dryas stadial (ca. 13.2 ka), deglaciation and termination of the Younger Dryas stadial (ca. 11.3 ka), Early Holocene cooling (ca. 8.8 ka), and Neoglacial (ca. 4.5, 2.9, 1.1 ka). Six intervening periods of incision and channel stability may also reflect either reduced sediment supply, drier hydroclimate, or both. The terrace chronology can be correlated to a variety of local and regional paleoclimate proxy records and corresponds well with periods of continental- and global-scale rapid climate change during the Holocene. The fluvial record demonstrates the geomorphic response and sensitivity of large river systems to changes in hydroclimate variability, which has important implications for inferring paleoenvironmental conditions in the region. [ABSTRACT FROM AUTHOR]

Chains of ponds are a discontinuous river type found in Australia. Their unusual morphology, important ecological functions and increasing rarity make them a priority for conservation, and yet very little research has investigated their physical structure, behaviour and evolution. This paper reconstructs the Holocene evolution and environmental history of Crisp's Creek, a headwater chain of ponds in the Southern Tablelands of NSW Australia. This history establishes baseline information on the physical template that can be used to assess a range of other biophysical processes and design appropriate river rehabilitation and management strategies for these rivers. Sedimentary aggradation began in the Late Holocene, at least 3.7–1.3 ka, broadly synchronous with aggradation phases at other sites in southeast Australia. Since European arrival in the Nineteenth Century, parts of the river incised, destroying intact ponds and smothering formerly swampy floodplains with post-incision alluvium. However, sections unaffected by incision provide a rare opportunity to examine the evolutionary trajectory of an intact variant of these rivers. This research deepens our understanding of the evolutionary context for contemporary river behaviour as relevant for designing appropriate and effective conservation and rehabilitation strategies for chains of ponds. [ABSTRACT FROM AUTHOR]

Packages of fluvial systems in the Lower Ganga plains (LGP) archive the changes in stratigraphic architecture induced by perturbations in the climatic system. In some parts of this landscape, where the fluvial sequences predominate, the role of climate in landsculpting is strongly indicated by the presence of sediment architecture. The present study is focused on the formation of alluvial plains of the Ajay River in the Rarh region that represent a region's environmental templates for understanding the landscape of LGP. The sedimentological, geomorphological, and optically stimulated luminescence (OSL) chronological investigations were attempted to document sedimentation patterns and the timing of deposition. The stratigraphic data from two exposed cliff sections and three boreholes are compared with proxy records to understand the Indian Summer Monsoon (ISM) controls on alluvial sedimentation for the last ~2.4 ka. The fluvial packages in the study area correspond to two significant channel phases: Period‐I (2.4–1.3 ka) and Period‐II (800–200 years ago). Period‐I is characterized by the episodes of floodplain development and lateral migration of the trunk river during Marine Isotope Stage (MIS) I, especially around 2 ka corresponding to the Roman Warm (RW) period in the Indian subcontinent. The sediment filling was high during ~2.4 ka due to ISM intensification, but in the later stage, the sedimentation was at a fairly steady rate. Conversely, Period‐II is characterized by flooding phenomena and aggradation of channel bodies across much of the present valley area during the last 800 years. The distinct flood events occurred during the times of significant shifts in ISM, from fluvial dormancy to sudden outbursts of monsoons (end of Little Ice Age [LIA] ~ 19th century), indicating that climatic patterns can be associated with the occurrences of abrupt flood events. The alluvial records fit well with the historical, instrumental, and published proxy data on the ISM validating the chronology and the potential of sedimentary archives for further studies related to the palaeoenvironment and palaeogeography. [ABSTRACT FROM AUTHOR]

This work presents the chronology of the Holocene filling of the Guadalentín Tectonic Depression (Murcia, SE Spain) combining 14C and OSL age data. This work studies the sediments and paleosols interbedded in the sedimentary sequence between Totana and Librilla, using as reference the Espuña Karting section (Alhama de Murcia), which has been fully sampled for its geochronological analysis. The entire dated sequences record the last c. 20–19 ka BP, although local basal travertine beds extend back to the Late Pleistocene (30–33 ka). Soil morphology and properties from dated paleosols record different environmental crises in SE Spain, but also a progressive aridification throughout the Holocene. The Chalcolithic Paleosol develops soon after c. 4.6–4.0 BP, nearly coinciding with the start of the Meghalayan stage, evidencing a drastic change from relatively humid to arid conditions, coincident with the crisis of the Copper Age civilizations in Spain. The Bronze Age paleosol also developed under arid but relatively more humid conditions, indicating a more important and longer gap in the sedimentary sequence soon after c. 2.5–2.7 ka BP. This stop in the sedimentation are correlative to the first stages of fluvial incision at basin center locations and the desiccation and fragmentation of the ancient wetlands coinciding with the collapse of the Bronze Age civilizations in SE Spain (Argaric Culture). During the Ibero-Roman Humid Period (IRHP), c. 2.6–1.6 ka BP, the last pedogenic cycle occurred under relatively humid conditions. This preluded the progressive establishment of exorheic fluvial environments as well as a period of paleoseismic activity in the area around 2.0–1.8 ka BP. [ABSTRACT FROM AUTHOR]

In this paper we will use an illustrative example to show the significance of rapid vertical movements inside floodplains as well as varying discharge values for the alteration of channel and sedimentation patterns during the Holocene. Concerning such relationships, well documented and well dated references from sedimentary records are rather rare. The developments within the lower Jarama Valley have been significantly supported by an interaction of tectonic activity, evaporite dissolution, and halokinetics that initiated rapid vertical movements over short distances and caused the formation of knick-points and gradient changes along the longitudinal floodplain profile. Furthermore, the specific Mediterranean climate caused highly variable discharges including extreme runoff peaks. The juxtaposition of different floodplain gradients gave rise to spatial and temporal changes of discharge patterns and channel geometry, which is reflected by varying sedimentation as well as erosion patterns. We have been able to confirm that alluvial thickening due to intense dissolution and subsidence has been a characteristic and frequently recurring feature during the Pleistocene. Moreover, we want to emphasize that also during the Holocene gradient adjustments exercised controlling influence on fluvial dynamics, in particular with regard to channel response. In fact, we found consistency between low and moderate gradients and meandering single channel patterns associated with overbank deposition in distal floodplain positions. Only a section with stronger inclination revealed evidences for multiple channel discharge patterns in form of gravelly braided river deposits. In comparison with recent discharge patterns and information from historical sources it appears that braided river deposition took place just within a short time frame between 5 and 3 ka cal. BP. This matches exactly a period of strong climatic aridity including highly variable precipitation and discharge patterns. From that we conclude, that in the first instance, gradient changes promoted the change of channel and discharge patterns, but however, specific overlap of the parameters gradient and runoff is considered to have been necessary to generate braided discharge pattern. A subsequent formation of braided patterns during the Late Holocene was presumably prevented by river entrenchment as well as a strong increase of sediment availability during the time of Roman colonization. On the basis of this study, we can establish a number of general relationships between floodplain gradient, runoff pattern, and channel response during the Holocene period that may help us to better understand fluvial behavior in various different areas. [ABSTRACT FROM AUTHOR]

James C. Knox was best-known for his work on Holocene and historical changes in fluvial systems, but he also had a long-standing interest in the effects of late Pleistocene periglacial environments on landscape evolution in parts of the Upper Mississippi River basin that were just outside the Laurentide Ice Sheet margin, or as Knox put it, ‘up in the refrigerator.’ Knox and others in the Quaternary community of the Midwestern U.S. often suggested that hillslope erosion was accelerated under periglacial conditions, so that glacial periods have had a dominant effect on the landscape we see today. This paper reviews the evidence and reasoning supporting that view in a study area of the Upper Mississippi basin bordered on three sides by ice margins of the last glaciation, including the Wisconsin Driftless Area and adjacent landscapes. Sparse but compelling paleoecological data and relict ice- or sand-wedge polygons provide clear evidence for a cold climate and widespread permafrost around the peak of the last glaciation. In highly dissected, relatively high-relief parts of the study area, the loess and soil stratigraphy on ridgetops and the colluvial mantles on steeper slopes are best explained by highly effective hillslope erosion, including solifluction, during and just after the Last Glacial Maximum. Knox used the post-depositional truncation of a loess unit to quantify contrasting late Pleistocene and Holocene sediment yields from a small Driftless Area watershed. While the late Pleistocene yield indicates accelerated erosion, it is still lower than modern sediment yields in many tectonically active or semiarid landscapes, and it may reflect deposition of highly erodible loess as well as effects of periglacial conditions. The views of Knox and other Midwestern geomorphologists on landscape evolution through glacial–interglacial cycles were highly influenced by the work of Robert V. Ruhe. Ruhe proposed that an episode of widespread erosion during and just after the Last Glacial Maximum can explain enigmatic aspects of Quaternary stratigraphy and the soil landscape on the Iowan Erosion Surface, a very low relief landscape of the study area. Ruhe's key evidence is still valid, though it needs to be separated from an implausible model of landscape evolution. Interpretation of the Iowan Erosion Surface and other low-relief landscapes just outside the ice margin also requires recognition of the profound effect of eolian processes on those landscapes under periglacial conditions. Many new insights on landscape evolution in the study area could result from wider application of cosmogenic nuclide-based methods to assess glacial–interglacial changes in basinwide rates of erosion and residence time of soils. Just as important, a need exists for much more field-based characterization of hillslope, fluvial, and eolian sediments for comparison with those of modern permafrost regions and past periglacial environments in Europe. [ABSTRACT FROM AUTHOR]

When dealing with current and past landscape evolution, a key issue addresses responses of geomorphic systems to the large number of influencing variables. Identifying morphodynamic phases and revealing interrelations with specific driving forces are demanding tasks for Quaternary research. In this paper, we present late Pleistocene and Holocene fluvial sedimentation patterns of three Western Mediterranean river catchments, namely Jarama River, Guadalete River and Guadalquivir River that extent along a climatic transect from semi-humid SW-Spain to semi-arid central Spain. These studies are based on extensive fieldwork conducted on 36 exposures and 13 drillings in floodplain positions. Field data is supported by geochemical analyses, while the chronological framework was obtained from the analyses of 70 radiocarbon samples. Results show distinct patterns of fluvial sedimentation as well as soil formation linked to floodplain stability for each river catchment. On regional or catchment scale, pollen stratigraphical correlation and comparison with lacustrine records show that fluvial dynamics have a strong reaction to climatic shifts, with phases of high fragility characterized by catchment erosion and floodplain sedimentation in response to climatic aridification events and phases of climate change in general. The comparison of the examined river systems reveals that periods of supra-regional floodplain sedimentation in several catchments occurred from 8.0 to 7.0, 5.0 to 3.8, 2.2 to 1.5, and around 1.0 as well as 0.4 ka cal. BP, while we found periods of supra-regional soil formation from 13.3 to 12.7, 7.0 to 5.1 (with a short interruption around 6.0 to 5.5 ka), 2.8 to 2.3 ka, 1.4 to 1.2 ka, and 0.8 to 0.5 ka cal. BP. Beside these consistencies we found deviating dynamic patterns that are apparently expressed in terms of differing onset and offset, differing durations, or even the lack of fluvial system response. The main reasons for this can be seen in different regional climate condition and impacts of further influencing factors, or in different levels of sensitivity of the river catchments that may be controlled by initial hydrological conditions, catchment size, or the degree of anthropogenic influence. A larger scale assessment shows that fluvial dynamic patterns are hardly comparable across entire Spain due to strong spatial heterogeneity of physiographic and climatic conditions on the Iberian Peninsula, in particular when areas are influenced by different circulation systems (e.g. regions influenced by the Atlantic Ocean vs. regions influenced by the Mediterranean Sea). However, the consideration of North Atlantic marine records reveals a certain coupling between North Atlantic coolings, atmospheric processes leading to arid climate over large parts of Spain, as well as increased landscape instability including strong fluvial sedimentation activity. Attendant atmospheric conditions are discussed. [ABSTRACT FROM AUTHOR]

This paper describes developments in the analysis and interpretation of Holocene fluvial chronologies over the past 25 years. Particular consideration is given to meta-analysis approaches pioneered by Macklin and Lewin (2003), using radiocarbon-dated fluvial deposits in Britain, which have transformed fluvial geochronologies and correlations with climate and land-use records worldwide. During the last decade methodological developments have addressed issues such as correction for the shape of the radiocarbon calibration curve in the probability analysis of dated fluvial units and for variable alluvial unit preservation. The number of regional database analyses of fluvial sedimentary archives has also expanded significantly during the past decade, with studies now available for Africa, the Mediterranean region, India, Ireland, New Zealand, Poland, the Rhine catchment and the UK. Methods for incorporating optically stimulated luminescence ages in the probability analysis have also been developed and are illustrated using the database of Eastern Mediterranean dated fluvial deposits. There is considerable potential for meta-analysis research to inform long-term flood risk assessment, to evaluate short-term climate and land-use change impacts on flooding and river behaviour, and to test landscape evolution models. [ABSTRACT FROM AUTHOR]

Mediterranean fluvial hydrology is characterised by decadal-to-multi-centennial length wet and dry episodes with abrupt transitions related to changes in atmospheric circulation. Since the mid-1990s site-based flood chronologies from slackwater deposits in bedrock rivers and regionally aggregated flood histories from alluvial deposits have developed increasingly higher resolution chronological frameworks, although regional coverage is still uneven. This paper analyses the spatial and temporal distribution of extreme Holocene hydrological events recorded in fluvial stratigraphy in the Iberian Peninsula (Spain and Portugal), southern France, southern Italy, Northern Africa (Morocco and Tunisia) and eastern Mediterranean (Greece, Crete, Turkey, Cyprus and Israel). This study constitutes the most comprehensive investigation of Holocene river flooding ever undertaken in the Mediterranean and is based on the analysis of 515 14 C and 53 OSL dates. It reveals that flood periods in different regions cluster into distinct time intervals, although region-wide flooding episodes can be identified at 7400–7150, 4800–4600, 4100–3700, 3300–3200, 2850–2750, 2300–2100, 1700–1600, 1500–1400, 950–800, ca. 300, 200–100 cal. BP. Periods with more frequent floods in the western Iberian region coincide with transitions to cool and wetter conditions and persistent negative NAO mode. In Northern Africa increased flood frequency coincides with periods of generally drier climate, while in the eastern Mediterranean there is a higher incidence of extreme flood events under wetter conditions. Our meta-data analysis identifies an out-of-phase pattern of extreme events across the Mediterranean over multi-centennial timescales, which is particularly evident between the western Iberian and eastern Mediterranean regions. This centennial-to-multi-centennial see-saw pattern in flooding indicates that bipolar hydroclimatic conditions existed in the Mediterranean during the Holocene. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to describe the late Holocene behaviour of rivers using an interdisciplinary approach combining fluvial geomorphology and subfossil trunk dendrochronology. The subfossil wood material collected along the rivers was investigated for dendrometric and dendrochronologic parameters. The research methods in these fields helped us to understand the effect of the fluvial environment on riparian trees and their records and helped in reconstructing the riparian palaeoenvironment. The study area consists of two rivers with different typologies but comparable sizes: the Moldova River, which features a braided to wandering channel in its lower reach, and the Siret River, which features a sinuous-meandering channel. Along the 100-km-long floodplain of the former and the 144-km-long floodplain of the latter, we found and sampled 77 subfossil trunks, of which 26 were subjected to 14 C dating. The resulting data consist of floodplain facies mapping data, electric resistivity measurements, absolute dates, and dendrometric and dendrochronologic data. The results indicate that during a 100-year period, the two rivers were sensitive to climate change and anthropogenic effects, particularly a narrowing of the active channel by 76% in the braided channel and 38% in the sinuous-meandering channel. During the past 3300–3000 YBP, the Moldova River maintained its braided style, whereas the sinuous-meandering style has been characteristic of the Siret River for the previous 6800–4600 YBP. The two distinct fluvial environments are recorded in the dendrometric structure of the trunks buried in the channel-fill sediments. The braided fluvial environment was more effective in uprooting riparian trees and incorporating them in the floodplain deposits, whereas the sinuous-meandering style of stream effectively buried tree trunks in lateral accretion lobes. Absolute and dendrochronologic dating allowed for the reconstruction of timelines of the felling of the trees and estimates of the magnitude of the responsible hydrological event. The flood events on the Siret River with a recurrence interval of 200 years ( Q max ~ 2500–2800 m 3 /s) were those most effective in destroying riparian forests, and the events on the Moldova floods with a 100-year recurrence interval ( Q max ~ 1200–1400 m 3 /s) were the most effective. Dendrochronology allowed for identification of wet phases (i.e., 3500–2900 YBP, 2200–2075 YBP, and 1000–800 YBP) and dry phases (e.g., 3200–3150 or 2775–2700 YBP, 1400 YBP). Finally, we draw attention to the potential for creating a highly replicable dendrochronological series spanning at least 7000 YBP. [ABSTRACT FROM AUTHOR]

The current model of mid-latitude late Quaternary terrace sequences, is that they are uplift-driven but climatically controlled terrace staircases, relating to both regional-scale crustal and tectonic factors, and palaeohydrological variations forced by quasi-cyclic climatic conditions in the 100 K world (post Mid Pleistocene Transition). This model appears to hold for the majority of the river valleys draining into the English Channel which exhibit 8–15 terrace levels over approximately 60–100 m of altitudinal elevation. However, one valley, the Axe, has only one major morphological terrace and has long-been regarded as anomalous. This paper uses both conventional and novel stratigraphical methods (digital granulometry and terrestrial laser scanning) to show that this terrace is a stacked sedimentary sequence of 20–30 m thickness with a quasi-continuous (i.e. with hiatuses) pulsed, record of fluvial and periglacial sedimentation over at least the last 300–400 K yrs as determined principally by OSL dating of the upper two thirds of the sequence. Since uplift has been regional, there is no evidence of anomalous neotectonics, and climatic history must be comparable to the adjacent catchments (both of which have staircase sequences) a catchment-specific mechanism is required. The Axe is the only valley in North West Europe incised entirely into the near-horizontally bedded chert (crypto-crystalline quartz) and sand-rich Lower Cretaceous rocks creating a buried valley. Mapping of the valley slopes has identified many large landslide scars associated with past and present springs. It is proposed that these are thaw-slump scars and represent large hill-slope failures caused by Vauclausian water pressures and hydraulic fracturing of the chert during rapid permafrost melting. A simple 1D model of this thermokarstic process is used to explore this mechanism, and it is proposed that the resultant anomalously high input of chert and sand into the valley during terminations caused pulsed aggradation until the last termination. It is also proposed that interglacial and interstadial incision may have been prevented by the over-sized and interlocking nature of the sub-angular chert clasts until the Lateglacial when confinement of the river overcame this immobility threshold. One result of this hydrogeologically mediated valley evolution was to provide a sequence of proximal Palaeolithic archaeology over two MIS cycles. This study demonstrates that uplift tectonics and climate alone do not fully determine Quaternary valley evolution and that lithological and hydrogeological conditions are a fundamental cause of variation in terrestrial Quaternary records and landform evolution. [ABSTRACT FROM AUTHOR]

Tropical peatlands are an important carbon reservoir; however, they are vulnerable to climate change, fire events, and human disturbances, and may become a significant carbon source if degraded. In this paper, we investigated the late Holocene record of vegetation change, peatland evolution, and C accumulation based on analysis of a sediment core through a Mauritia-flexuosa palm dominated swamp (locally called " aguajal ") in the Madre de Dios region in southern Peru to better understand tropical peatland dynamics. Sedimentation commenced within shallow water, ponded on an impervious substrate, perhaps within an abandoned river channel or oxbow lake (1380–820 cal yr BP) located adjacent to a steep escarpment with terra firme (upland) rainforest above and lateral to floodplain forests. This was followed by the development of marsh (820–640 cal yr BP). A closed-canopy Mauritia flexuosa -dominated palm swamp was subsequently established (640300calyr BP) which later changed into an open canopy and mixed Mauritia - Hedyosmum palm swamp (300 cal yr BP to present). Two major changes in peat and C accumulation rates were observed: (1) onset of peat and C accumulation at 820 cal yr BP and (2) decrease of peat and C accumulation after 520 cal yr BP. Comparisons of our results with palaeoecological records from aguajales in northern Peru suggest that the dynamics were different in this region. The peat and C accumulation rates in our study core in southern Peru were ca. 4 mm yr−1 and ca. 200 g m−2 yr−1 faster, similar to a few sites in northern Peru. Aguajales in Madre de Dios region in southern Peru are an important carbon sink. Analyzing the dynamics of aguajales which are a kind of typical peatlands in Amazonia and comparing among different sites allows exploration and prediction of regional peatlands' development under the potential future impact of natural changes. • First study of a palm peatland (aguajal) development in Madre de Dios region, southern Peru • This study includes late Holocene vegetation dynamics, peat and C accumulation of the aguajal • Controlling factors in the dynamics are fluvial changes and climate • Comparisons with northern Peru suggest different vegetation succession • Peat and C accumulation rates in Madre de Dios were faster, similar to a few sites in northern Peru [ABSTRACT FROM AUTHOR]

The term "Bergstraßenneckar" (BSN) refers to an abandoned course of the river Neckar. It flowed in a northern direction east of the river Rhine in the eastern part of the northern Upper Rhine Graben in southwestern Germany. The former meandering course merged with the Rhine ca. 50 km further north of the site of the present-day confluence near Mannheim. The palaeo-channels are still traceable by their depressional topography, in satellite images and by the curved boundaries of adjacent settlements and land parcels. In the plan view, satellite and aerial images reveal a succession of meander bends, with older bends being cut off from younger channels. Based on stratigraphic investigations of the channel infill in the northern part of the BSN, fluvial activity is assumed from ca. 14 500 years ago until the onset of the Holocene. We present results of the first stratigraphic investigations at two sites in the southern part of the BSN near Heidelberg (Rindlache, Schäffertwiesen), together with results from granulometric, carbonate and organic content analyses, as well as electrical resistivity tomography (ERT) measurements. The data clearly show a change from high-energy fluvial bedload (sand, gravel) to low-energy fluvio-limnic suspended load (organoclastic and calcareous mud) and to peat formation. Radiocarbon dating indicates a time lag of ca. 1500 years between the cut-off meander site (Schäffertwiesen) and the younger site (Rindlache) that was possibly still active until the present-day confluence near Mannheim was established and the BSN eventually became abandoned. Our preliminary data conform with the pedo-sedimentary evidence from the northern BSN, but slight differences in the stratigraphic pattern of the youngest channels are identified: whilst for the younger channel sections of the northern BSN the channel-bottom facies (sand, gravel) is directly overlain by peat, the channel at Rindlache shows substantial intervening mud deposition, which is interpreted as suspension load from flooding by the new Neckar channel nearby. The study shows that more chronostratigraphic data from channel sections of the southern BSN are needed to better constrain the timing of the fluvial activity and to decipher the reasons for the abandonment of the BSN. These data are also necessary to better understand the pattern of temporary reactivation of the BSN channels across the Holocene and their usage by humans, which can be deduced from historical sources and archaeological data. Kurzfassung: Mit dem Begriff Bergstraßenneckar (BSN) wird der heute inaktive mäandrierende Lauf des Neckars bezeichnet, der im Spätglazial dem östlichen Rand des nördlichen Oberrheingrabens folgte. Von dort floss der BSN dem Rhein bei Trebur zu, bevor er sein Mündungsgebiet um ca. 50 km nach Süden in den Raum Mannheim verlegte. Die morphologischen Strukturen der verlandeten Neckarbetten sind in Satellitenbildern, im Mikrorelief und am Verlauf von Flurgrenzen erkennbar. Auf Basis von stratigraphischen Untersuchungen an Rinnenfüllungen des nördlichen BSN wird die Aktivität dieses Flusslaufs von ca. 14 500 Jahren vor heute bis zum Beginn des Holozäns angenommen. Hier präsentieren wir die ersten stratigraphischen Untersuchungen zweier Lokalitäten im südlichen Bereich des BSN (Rindlache, Schäffertwiesen) gemeinsam mit granulometrischen, Organik-, Karbonat- und widerstandsgeoelektrischen Daten. Die Ergebnisse reflektieren deutlich den Übergang von einer aktiv durchflossenen Rinne (Sand- und Kiesfazies) hin zu Verlandung unter fluvio-limnischen Bedingungen (organoklastische und kalkreiche Feinkornablagerungen) mit abschließendem Torfwachstum. Die bislang verfügbaren 14 C-Daten deuten auf einen zeitlichen Versatz der Aktivität von ca. 1500 Jahren zwischen der morphologisch älteren Mäanderschlinge (Schäffertwiesen) und der jüngeren Lokalität (Rindlache) hin, die möglicherweise noch zu der Zeit die Hauptrinne bildete, als die Mündung nach Süden in den Raum Mannheim verlagert wurde. Die hier präsentierten vorläufigen Daten sind mit der bestehenden Chronologie am nördlichen BSN vereinbar, wenngleich auch Unterschiede in der stratigraphischen Abfolge der Verlandungssedimente in den zuletzt aktiven Rinnen identifiziert werden: Während im Norden die fluviale Sand- und Kiesfazies unmittelbar von Niedermoortorf überlagert wird, sind in den jüngeren Rinnen im Süden Feinkornablagerungen zwischengeschaltet, die als Suspensionsfracht periodischer Überflutungen möglicherweise ausgehend vom nur wenige Kilometer entfernten neuen Neckarlauf interpretiert werden. Die Ergebnisse verdeutlichen, dass weitere chrono-stratigraphische Untersuchungen an Rinnenstandorten des südlichen BSN erforderlich sind, um den Zeitrahmen und die Abfolge der fluvialen Aktivität besser eingrenzen und die Ursachen für die Laufverlagerung besser definieren zu können. Zudem ergäben sich so detailliertere Hinweise auf die temporäre Reaktivierung bestimmter Abschnitte des BSN über das gesamte Holozän hinweg sowie auf deren Nutzung durch den Menschen, die in historischen Quellen und durch archäologische Daten belegt ist. [ABSTRACT FROM AUTHOR]

The French Upper Rhine alluvial plain is characterized by a complex system of paleochannels inherited from Late Glacial to Holocene fluvial dynamics of the Rhine and Ill river systems, among other smaller rivers. These paleochannels represent valuable archives for understanding and reconstructing the fluvial and landscape evolution of the area. However, the Holocene temporal trajectories of the paleochannels, in response to a range of environmental changes, remain poorly understood. This study presents a detailed and systematic mapping and characterization of an extensive network of paleochannels spanning the entire width (19 km) of a reach of the central French Rhine plain. Based on qualitative and quantitative lidar analysis, field investigations, and provenance investigations of paleochannel infill sequences, five distinct paleochannel groups (PG 1 to PG 5) were identified in the study area. These paleochannel groups differ considerably regarding their channel patterns, morphological characteristics, and sedimentary sources of the infilling sediments. The interpretation of the different datasets indicates that the development of these different paleomorphologies is attributed to significant changes in hydro-geomorphodynamic processes in the area during the Holocene, especially lateral migrations of the Rhine and Ill rivers. The findings reported here are promising and will have significant implications for reconstructing the long-term (Late Glacial to Holocene) evolution of the Upper Rhine fluvial hydrosystem in response to various controlling factors. Kurzfassung: Die französische Oberrheinebene ist durch ein komplexes System von ehemaligen Fließrinnen gekennzeichnet, die aus der spätglazialen bis holozänen fluvialen Dynamik des Rhein- und Ill-Systems sowie einiger anderer kleinerer Flüsse stammen. Diese Fließrinnen stellen wertvolle Archive dar, die für das Verständnis und die Rekonstruktion der fluvialen und landschaftlichen Entwicklung des Gebietes von zentraler Bedeutung sind. Die zeitliche Entwicklung der Fließrinnen im Holozän, als Reaktion auf die Veränderung einer Reihe von Umweltbedingungen, ist jedoch nach wie vor nur unzureichend bekannt. Diese Studie präsentiert eine detaillierte und systematische Kartierung und Charakterisierung eines ausgedehnten Netzwerks von ehemaligen Fließrinnen, das sich über die gesamte Breite (19 km) eines Abschnitts der zentralen französischen Rheinebene erstreckt. Auf Grundlage von qualitativen und quantitativen lidar-Analysen, sowie durch Feld- und Provenienzuntersuchungen von Sedimentfüllungen wurden im Untersuchungsgebiet fünf verschiedene Rinnengruppen (PG 1 bis PG 5) identifiziert. Diese Gruppen unterscheiden sich erheblich in Bezug auf ihre Rinnenmuster, morphologischen Merkmale und Sedimentherkunft. Die Interpretation der verschiedenen Datensätze deutet darauf hin, dass die Entwicklung dieser unterschiedlichen Paläo-Morphologien auf signifikante Veränderungen der hydro-geomorphodynamischen Prozesse in diesem Gebiet während des Holozäns zurückzuführen ist, insbesondere auf die seitlichen Verlagerungen von Rhein und Ill. Die hier vorgestellten Ergebnisse sind vielversprechend und bilden die Basis für eine Rekonstruktion der langfristigen (spätglazialen bis holozänen) Entwicklung des fluvialen Oberrhein-Hydrosystems in Abhängigkeit von verschiedenen Einflussfaktoren. [ABSTRACT FROM AUTHOR]

'Complex response' (Schumm, 1973, Geomorphic thresholds and complex response of drainage systems. In Morisawa, M. (ed.), Fluvial Geomorphology. Binghamton: New York State University Publications: 299‐310) describes situations in which a single event triggers a series of progressively damped morphological and sedimentary adjustments within a catchment. Schumm and Parker's (1973, Implications of complex response of drainage systems for Quaternary alluvial stratigraphy. Nature 243: 99–100) classic stream table experiment of drainage system development showed that one baselevel fall event could result in formation of two sets of paired river terraces that need not be related to additional external (e.g., climate) influences. Despite its enduring popularity in fluvial geomorphology, large‐scale and long‐term field evaluations of Schumm and Parker's complex response model are very limited. Here, we report on a multi‐millennial, multi‐catchment field experiment in south‐western Crete where a high‐magnitude earthquake (estimated magnitude 8.3–8.5) on 21 July 365 ce resulted in up to 9 m of instantaneous uplift over a land area exceeding 6000 km2. Geomorphological, sedimentological, and chronological investigations were used to investigate the erosional and depositional histories in three catchments with outlets uplifted by the 365 ce event. These catchments were compared with the Anapodaris catchment in south central Crete where baselevel was not significantly affected by the earthquake. Although all uplifted catchments experienced valley floor incision, this occurred hundreds of years after 365 ce during a period of wetter climate. The number and age of trunk stream incision and aggradation phases are similar in both uplifted and non‐uplifted catchments, indicating that river responses following the 365 ce uplift event have not followed complex response trajectories in the form documented by Schumm and Parker (1973). This finding highlights the need for rigorous evaluation of other catchment or river response concepts, including through the combined use of laboratory experimental results, field data, and geochronology. In an era of rapid environmental change, characterizing and anticipating catchment and river system response increasingly will depend on a healthy interplay between different investigative approaches. [ABSTRACT FROM AUTHOR]

Problem definition: Geomorphic phenomena have a primary impact on the locations, dispersions, spheres of influence, physical developments, and morphologies of settlements. In other words, geomorphic units and topographic elements are very important in physical development of settlemenets and play a significant role in the spatial distribution patterns of cities, as well as influencing the morphologies, constructions, and textures of them. Accordingly, location, orientation of mountains, and the type of landform have an undeniable role in issues such as urban construction and urban population movement. Nowadays, the increase in human population has created an increasing need to land occupation around residential areas; this is closely related to the geomorphic indicators of each area. Then, if the process of creating new settlements is formed with no proportion to natural capacities and facilities, it will create adverse effects and results in the physical-biological problems of cities, such as natural hazards, which cause disturbing the balance of the environment and disrupting services. Evidence of hazards in recent years show that most developing countries, especially in their rural areas, have high-risk physical structures that are often vulnerable to hazards. Therefore, based on various studies, there is a close relationship between geomorphological components and human settlements. These components have sometimes caused the growths and developments or emergence and expansions of settlement centers, which have sometimes appeared to be dangerous and repulsive. Therefore, recognizing the natural environment characteristics and the features and capabilities of landforms is important and necessary for identifying suitable and sustainable points for the creation and development of human settlements. Purpose: The purpose of this study was to investigate and analyze the roles of geomorphic features and components in the formations, developments, evolution, and patterns of settlements around Shirkuh Mountain in the arid and warm region of Central Iran. Methodology: To do this research, topographic and geological maps, Google Earth images, and, most importantly, field studies and observations were used. This study was based on descriptive phenomenological method. Accordingly, geomorphological factors, including altitude, direction, and lithology, geomorphic features, including fluvial landforms, such as alluvial plains, alluvial fans, plains, lake and river terraces, and glacial landforms like cirques, valleys, and glacial terraces were surveyed and analyzed. Then the role of each factor in the creation, development, and transformation of the settlements was studied and evaluated. Results: The results showed a different settlement pattern on the northern and southern slopes, as well as the western and eastern slopes of Shirkouh. Most of the settlements of the southern slopes were located at high altitudes between 2450-2550 m along the ice-water equilibrium line. However, the settlement range elevation on the northern slopes varied between 1700 and 1650 m, while fluvial landforms, such as river terraces, alluvial fans, and pediments, had not played a role in the formations of these settlements even with relatively good water resources unlike most other parts of Iran and the world. The settlement on glacial landforms at altitudes above 2000 m probably dated back to very dry and hot periods and the settlement on the edge of the current playa depression referred to the Late Quaternary cold periods. The formations and developments of settlements in the two completely different environments and climatic conditions, namely the high altitudes and the margins of the downstream depressions, indicated a climate change and consequently vertical displacements of the settlements along the Holocene. The results also revealed that other factors, such as geographical direction, altitude, slope, and lithology, had played an effective role in the densities and developments of these settlements. Innovation: This study showed that the alluvial fans had never been used to build a settlement anywhere in the study area until the last 3 decades due to heavy rainfall and heavy flooding. Although according to previous studied, most of the settlements in Iran, whether urban or rural settlements, especially in the central and eastern parts, have been located on alluvial fans, even the prehistoric settlements. Also, this study showed that glacial landforms located at the high altitudes had been the most desirable place for the creation and transformation of settlements due to specific climatic reasons. [ABSTRACT FROM AUTHOR]

The Brazilian territory has a very extensive coastline, with more than 7500 km, and the largest and complex fluvio-marine archipelago on the planet, centred by Marajó Island, located in the Amazon River mouth, representing a key area for long-term sustainable management of coastal resources under threat of ongoing climate changes. Our study carried out the first detailed geoenvironmental stratification analysis to increase the knowledge of the largest and most heterogenous fluvial-estuarine landscape worldwide, and important sentinel of the global marine ecosystem's changes. Marajó Island is a very fragile and dynamic territory under global sea-level rise, demanding studies on a long-term response to such impacts. We used remote sensing technics to carry out the geoenvironmental stratification, coupled with soil characterization and landscape description. The results highlight the local complex social and environmental features and interplays, recording widespread evidence of part indigenous occupation (335–527 yr. B.P.) on present-day soils. The impacts of sea-level rise on mangrove ecosystem's, and old weathering soil profiles developed between 5300 and 3300 years (BP) during Holocene warmer, well-drained phases. The complexity of landscapes of the Amazon River mouth, and their dynamics, account for varying phases and modes of human occupation at the largest fluvio-marine environment. Soils are key elements, both influencing the human-constructed landscapes, and recording the physical and chemical inheritances of such cultural memories conciliate with signs of long-term climate change. Under constant processors of climate change, and accompanying human settlement dynamics, Marajó Island represents a remarkable laboratory to investigate how long-term environmental changes affect sustainable management resources of a large and fragile tropical estuary. [ABSTRACT FROM AUTHOR]

The headwaters of fluvial systems on the East European Plain between the boundaries of the Marine Isotope Stage 2 (MIS 2) and MIS 6 glaciations evolved during the last 150,000 years. At least three main events of high surface runoff caused intensive erosion: at the end of MIS 6, at the end of MIS 2 and in the Middle Holocene. Erosion developed in the territory with variable resistance of geological substrate, from hard-to-erode tills to weak sandy deposits. All erosional features in moraines formed in the pre-Holocene time. Even relatively large forms, such as balkas (small dry valleys), have not yet reached concave longitudinal profiles. A general tendency of their development was deepening. Short episodes of incision occurring during climatic events with increased water flow alternated with long periods of stabilization. Sand-covered areas are most favorable for linear erosion. The gullies formed in the Middle Holocene developed concave longitudinal profiles. The diversity of catchment areas, initial slope inclinations and sediment properties causing their resistance to erosion led to greater differences in the relief features and evolution of the upper reaches of the fluvial systems within the MIS 6 glaciation area compared to the more uniform landscape conditions in the extraglacial regions. [ABSTRACT FROM AUTHOR]

Information on past dryland environments is commonly derived from geomorphological landforms and sediments ('geoproxies'). The Okavango Delta in the middle Kalahari, Botswana, has been subject to a long history of arid–humid transitions but its potentially rich archive of fluvial geoproxies is largely untapped. Previous palaeoenvironmental studies in the Delta region have focused mainly on aeolian dunes, lacustrine beach ridges, and rare pollen sequences in surrounding locations, and the Delta's channel dynamics have remained poorly constrained, both chronologically and in quantitative palaeohydrological terms. Focusing on the Delta's Xugana region, we present the first optically stimulated luminescence ages for palaeochannel fills and scroll bars, revealing significantly enhanced fluvial activity in the ~7–4 ka interval. Along 120–150 m‐wide, sand‐bed, sinuous palaeochannels, lateral migration and bend cutoffs were driven by palaeodischarges up to ~350–450 m3 s−1, at least nine times those of the present‐day channels. These palaeochannels represent the last major phase of meander activity in the middle and lower Delta. The palaeodischarges imply significantly higher rainfall over the catchment in the mid Holocene, possibly resulting from a southwards shift of the African tropical rainbelt. Over the last few thousand years, diminished fluvial activity in the Xugana region has continued; <20 m‐wide channels with discharges typically <40 m3 s−1 have been more laterally stable, albeit subject to local avulsions. These findings provide the 'missing link' between evidence for past intervals of enhanced rainfall in the Delta's tributary catchments in the northwest and west and the filling of large lacustrine basins to the southeast and east. The findings contribute to improved understanding of changing Kalahari hydroclimates and support growing evidence indicating that the mid to late Holocene was a time of significant fluvial transformation across many of the world's drylands. [ABSTRACT FROM AUTHOR]

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Framed into a robust stratigraphic context, multivariate analyses on the Holocene palaeobiological record (pollen, benthic foraminifers, ostracods) of the Po coastal plain (NE Italy) allowed the investigation of microtidal ecosystems variability and driving parameters along a 35‐km‐long land–sea transect. Millennial‐scale ecosystem shifts are documented by coeval changes in the meiofauna, reflecting variations in organic matter–water depth (shallow‐marine environments) and degree of confinement‐salinity (back‐barrier settings). In‐phase shifts of vegetation communities track unsteady water‐table levels and river dynamics in freshwater palustrine areas. Five environmental–ecological stages followed one another crossing four tipping points that mark changes in relative sea level (RSL), climate and/or fluvial regime. At the culmination of Mediterranean RSL rise, after the 8200 event, remarkable growth of peatlands took place in the Po estuary, while low accumulation rates typified the shelf. At the transgressive–regressive turnaround (~7000 cal a bp), the estuary turned into a delta plain with tidally influenced interdistributary embayments. River flow regime oscillations after the Climate Optimum (post‐5000 cal a bp) favoured isolation of the bays and the development of brackish wetlands surrounded by wooded peatlands. The youngest threshold (~800 cal a bp), which led to the establishment of the modern delta, reflects a major avulsion of the Po River. [ABSTRACT FROM AUTHOR]

Lowland multiple-channel rivers are characterised by floodplain-corridor heterogeneity, high ecological and heritage value, and can be in quasi-stable states. This holistic study of a surviving temperate zone example (Culm, UK) uses geomorphological mapping, 14C, direct sediment dating (OSL, fallout radionuclides), and palaeoecology. This reveals the evolution of a channel-floodplain system from an initial braided state in the Late Pleistocene to its late Holocene anastomosing state. After the Pleistocene-Holocene transition the reduced channel system incised into its braid-plain, only able to rework gravels locally due to reduced competence in relation to inherited bounding sediment calibre. This resulted in the creation of terrace islands, palaeochannels, and a stable anastomosing pattern dominated by channel junctions, bifurcations and palaeochannel intersections. Survey, coring and excavation reveal a persistence of mid-channel bars and riffles at channel junctions, and where channels crossed palaeochannel fills. In common with most other European lowland rivers this system evolves in the later Holocene due to both climate and catchment changes with a major hydrological critical transition in the mid-Holocene (c. 5300 BP). However, in the case of the Culm, the increase in fine sediment supply often seen in lowland catchments in the Middle-Late Holocene, occurred later, and was insufficient to convert the system to a single medium-low sinuosity channel-floodplain. This allowed the persistence of high heterogeneity and biodiversity (including the persistence of riffle beetles) as part of multiple-scales of non-uniformity. Indeed the pool-riffle persistence is an example of this system's non-uniformity, being due, at least in part, to the effects of previous channel history. This paper reveals why this river survived in a multichannel state, and by implication, why others did not. These results are being used in the bespoke eco-heritage management of the Culm, but could also inform the restoration of other former multi-channel lowland temperate river systems worldwide. • Anastomosing channel system in SW England in quasi-equilibrium due to co-occurrence of inherited boundary conditions with dynamic fluvial processes. • Temporal pattern of channel abandonments reflects climate late-Holocene climate change and late rise in fine-sediment supply. • Simple catchment model suggests that mid Holocene low discharge promoted lack of channel change and sedimentation. • Some riffles/mid channel bars formed by fluvial response to inherited floodplain features. • Persistence of complex channel pattern promoted high biodiversity including persistence of riffle beetle species. [ABSTRACT FROM AUTHOR]

Organic and inorganic geochemical analyses on sediments from Preto Lake, a central Amazon basin floodplain water body, were used to document hydrological changes of the Solimões River during the late Holocene. Between 3600 and 400 cal yr BP, Preto Lake received smectite-rich sediment from the Solimões River, with high concentrations of Al (~ 53 × 103 ppm) and Si (~ 210 × 103 ppm). The high detrital input suggests there was a direct connection between Preto Lake and the main river channel. High river inflow maintained lake stage and was responsible for the contribution to sediments of phytoplankton-derived organic matter. Low sediment organic carbon concentrations characterized this period (mean ~ 3.8 wt%), probably because of dilution by river-borne lithogenic matter. Although the river inputs remained high, abrupt increases in TOC content around 1800 and 1200 cal yr BP suggest brief increases in fluvial nutrient supply to Preto Lake. During the last 400 cal yr, substantial declines in smectite (mean 40%), Al (~ 29 × 103 ppm) and Si (138 × 103 ppm) suggest the establishment of a semi-isolated lake, with reduced river inflow. A large proportion of C3-plant-derived organic matter, supplied by runoff from the kaolinite-rich watershed, was observed during this period, and was accompanied by high autochthonous primary production, driven by development of an aquatic macrophyte community. This change in sediment organic matter source accounted for the greater TOC content (~ 20%) of sediments deposited during this period. Although Holocene climate change was an important control on fluvial sediment supply to upper and lower Amazon Basin floodplain lakes, sedimentation processes in Preto Lake can also be linked to changes in the river's course. The transition to a semi-isolated lake could have been a consequence of lateral and vertical sediment accretion, which formed a natural levee that blocked fluvial input to Preto Lake. [ABSTRACT FROM AUTHOR]

The volume and grain‐size of sediment supplied from catchments fundamentally control basin stratigraphy. Despite their importance, few studies have constrained sediment budgets and grain‐size exported into an active rift at the basin scale. Here, we used the Corinth Rift as a natural laboratory to quantify the controls on sediment export within an active rift. In the field, we measured the hydraulic geometries, surface grain‐sizes of channel bars and full‐weighted grain‐size distributions of river sediment at the mouths of 47 catchments draining the rift (constituting 83% of the areal extent). Results show that the sediment grain‐size increases westward along the southern coast of the Gulf of Corinth, with the coarse‐fraction grain‐sizes (84th percentile of weighted grain‐size distribution) ranging from approximately 19 to 91 mm. We find that the median and coarse‐fraction of the sieved grain‐size distribution are primarily controlled by bedrock lithology, with late Quaternary uplift rates exerting a secondary control. Our results indicate that grain‐size export is primarily controlled by the input grain‐size within the catchment and subsequent abrasion during fluvial transport, both quantities that are sensitive to catchment lithology. We also demonstrate that the median and coarse‐fraction of the grain‐size distribution are predominantly transported in bedload; however, typical sand‐grade particles are transported as suspended load at bankfull conditions, suggesting disparate source‐to‐sink transit timescales for sand and gravel. Finally, we derive both a full Holocene sediment budget and a grain‐size‐specific bedload discharged into the Gulf of Corinth using the grain‐size measurements and previously published estimates of sediment fluxes and volumes. Results show that the bedload sediment budget is primarily comprised (~79%) of pebble to cobble grade (0.475–16 cm). Our results suggest that the grain‐size of sediment export at the rift scale is particularly sensitive to catchment lithology and fluvial mophodynamics, which complicates our ability to make direct inferences of tectonic and palaeoenvironmental forcing from local stratigraphic characteristics. [ABSTRACT FROM AUTHOR]

The southern Kachchh Mainland (SKM) of western India, situated in a seismically active intraplate region with a considerable Quaternary landscape, provides an opportunity to reconstruct the roles of climate and tectonics. Employing geomorphology, detailed sedimentology supported by geochemistry and optical dating, we integrate the fluvial to fluvio‐marine records to evaluate the potential of dryland environments in archiving the palaeo‐events. The climate reconstructions suggest that the fluvial systems have responded to the variations in monsoonal strength through widespread aggradation during 57 until 41 ka, corresponding to the later part of the MIS‐3. Following this, a relative weakening of monsoon and onset of aridity is observed between 28 and 11 ka, with short spells of enhanced monsoon. The monsoonal conditions again strengthened during 11 to 6 ka, reaching its maximum during the Early Holocene optima, which triggered a sea‐level rise during the Middle Holocene period, that is, 6 to 3 ka. Following this, the sequences incised in response to the relative sea‐level fall to the present level in post 3 ka. We have also employed this OSL ages to reconstruct the phases of aggradation and incision of valley fill sediments/estuarine tidal terraces from the SKM during the last 57 ka. The present study illustrates and contributes to the advancement in understanding of complex processes and their influence on climatic/tectonic signals in dryland landscape as well as their decoupling. [ABSTRACT FROM AUTHOR]

Permafrost ground is one of the largest repositories of terrestrial organic carbon and might become or already is a carbon source in response to ongoing global warming. With this study of syngenetically frozen, ice-rich and organic carbon (OC)-bearing Yedoma and associated alas deposits in central Yakutia (Republic of Sakha), we aimed to assess the local sediment deposition regime and its impact on permafrost carbon storage. For this purpose, we investigated the Yukechi alas area (61.76495 ∘ N, 130.46664 ∘ E), which is a thermokarst landscape degrading into Yedoma in central Yakutia. We retrieved two sediment cores (Yedoma upland, 22.35 m deep, and alas basin, 19.80 m deep) in 2015 and analyzed the biogeochemistry, sedimentology, radiocarbon dates and stable isotope geochemistry. The laboratory analyses of both cores revealed very low total OC (TOC) contents (<0.1 wt %) for a 12 m section in each core, whereas the remaining sections ranged from 0.1 wt % to 2.4 wt % TOC. The core sections holding very little to no detectable OC consisted of coarser sandy material were estimated to be between 39 000 and 18 000 BP (years before present) in age. For this period, we assume the deposition of organic-poor material. Pore water stable isotope data from the Yedoma core indicated a continuously frozen state except for the surface sample, thereby ruling out Holocene reworking. In consequence, we see evidence that no strong organic matter (OM) decomposition took place in the sediments of the Yedoma core until today. The alas core from an adjacent thermokarst basin was strongly disturbed by lake development and permafrost thaw. Similar to the Yedoma core, some sections of the alas core were also OC poor (<0.1 wt %) in 17 out of 28 samples. The Yedoma deposition was likely influenced by fluvial regimes in nearby streams and the Lena River shifting with climate. With its coarse sediments with low OC content (OC mean of 5.27 kg m -3), the Yedoma deposits in the Yukechi area differ from other Yedoma sites in North Yakutia that were generally characterized by silty sediments with higher OC contents (OC mean of 19 kg m -3 for the non-ice wedge sediment). Therefore, we conclude that sedimentary composition and deposition regimes of Yedoma may differ considerably within the Yedoma domain. The resulting heterogeneity should be taken into account for future upscaling approaches on the Yedoma carbon stock. The alas core, strongly affected by extensive thawing processes during the Holocene, indicates a possible future pathway of ground subsidence and further OC decomposition for thawing central Yakutian Yedoma deposits. [ABSTRACT FROM AUTHOR]

In Córdoba Province, Argentina, the population uses groundwater from confined aquifer systems (CASs) for different activities. Therefore, it is necessary to carry out comprehensive studies in order to plan more sustainable use considering that groundwater renewal times can be of several thousands of years. The objective of this research is to evaluate groundwater age in confined aquifers based on hydraulic and isotopic methods. The CASs present variable extension, are multilayered and formed by thin (4–6 m) sand-pebble lenses, and are linked to Neogene fluvial paleosystems. These layers are situated at different depths (120–400 m) and interbedded with thick clay strata. The interpretations made from 2H, 18O, and 3H results and hydraulic calculations suggest that the groundwater is old. Furthermore, an age gradient was observed that increases with depth and flow direction. The 14C ages obtained for the CASs labeled A2, C, and D were 3.6–1.1 ka BP, 10.8 ka BP, and 46.0–40.5 ka BP, respectively. These results indicate that A2 and C contain groundwater recharged during Holocene cold periods, between the Little Ice Age and the ending of the Holocene Climatic Optimum and during the last glaciation. The D CAS contains paleowater that was recharged during the Pleistocene. [ABSTRACT FROM AUTHOR]

Thick bay-fill sequences that often culminate in strandplain development serve as important sedimentary archives of land-ocean interaction, although distinguishing between internal and external forcings is an ongoing challenge. This study employs sediment cores, ground-penetrating radar surveys, radiocarbon dates, palaeogeographic reconstructions and hydrodynamic modelling to explore the role of autogenic processes - notably a reduction in wave energy in response to coastal embayment infilling - in coastal evolution and shoreline morphodynamics. Following a regional 2 to 4 m highstand at ca 5·8 ka, the 75 km2 Tijucas Strandplain in southern Brazil built from fluvial sediments deposited into a semi-enclosed bay. Holocene regressive deposits are underlain by fluvial sands and a Pleistocene transgressive-regressive sequence, and backed by a highstand barrier-island. The strandplain is immediately underlain by 5 to 16 m of seaward-thickening, fluvially derived, Holocene-age, basin-fill mud. Several trends are observed from the landward (oldest) to the seaward (youngest) sections of the strandplain: (i) the upper shoreface and foreshore become finer and thinner and shift from sand-dominated to mud-dominated; (ii) beachface slopes decrease from >11° to ca 7°; and (iii) progradation rates increase from 0·4 to 1·8 m yr−1. Hydrodynamic modelling demonstrates a correlation between progressive shoaling of Tijucas Bay driven by sea-level fall and sediment infilling and a decrease in onshore wave-energy transport from 18 to 4 kW m−1. The combination of allogenic (sediment supply, falling relative sea-level and geology) and autogenic (decrease in wave energy due to bay shoaling) processes drove the development of a regressive system with characteristics that are rare, if not unique, in the Holocene and rock records. These findings demonstrate the complexities in architecture styles of highstand and regressive systems tracts. Furthermore, this article highlights the diverse internal and external processes and feedbacks responsible for the development of these intricate marginal marine sedimentary systems. [ABSTRACT FROM AUTHOR]

The development of the Ohře River near Žatec between the Late Glacial Maximum (LGM) and present time was studied to obtain its natural trajectory and thus to understand the role of human impact on floodplain development. The study was based on geomorphic research, sampling and dating fluvial sediments by optically stimulated luminescence (OSL) and anthropogenic contamination by Sn since 16th century. During the LGM and the Pleistocene/Holocene transition (P/H), the river valley was shaped by large, incising meanders creating the entire valley floor. The Holocene river, due to decreased channel forming discharges, only slowly continued the LGM and P/H trajectory by cut-offs of the large palaeomeander necks and channel belt narrowing and incision. The last Holocene incision step was likely triggered by hydrological extremes of the Little Ice Age. The LGM and P/H Ohře River consequently changed from meandering to low sinuous, incised in the valley floor; this incision was completed by river engineering in the 20th century. The Ohře River development can thus be rationalised neither by traditional terrace-step formation model nor by model of the Anthropogenic aggradation. [ABSTRACT FROM AUTHOR]