Paleohydraulic investigation of the Ebro Basin: Implications for Mars

2021 ◽  
Author(s):  
Heath Geil-Haggerty
Keyword(s):  
Water Discharge ◽  
Sedimentary Basins ◽  
Mass Conservation ◽  
Sediment Supply ◽  
Sediment Flux ◽  
River Channels ◽  
Ebro Basin ◽  
Fluvial Systems ◽  
Sediment Size ◽  
Basin Scale

<p>The stratigraphy preserved in Earth’s sedimentary basins offers a record of how landscapes have evolved with time.  This stratigraphy provides insights into the dynamic processes that shaped the surface of the earth.  Fluvial stratigraphy contains many elements that can be used to recreate past conditions in ancient river channels.  Paleohydraulic reconstruction uses measurements of fluvial stratigraphy to model the conditions in the system that created them.  This allows us to answer questions related to water discharge, sediment flux, and duration of fluvial activity.  These are key questions when investigated in the context of Mars.  Paleohydraulic models can be used as compelling analogs for similar systems on Earth as well as Mars and other rocky planets.           </p><p>This study examines what the record of Oligocene-Miocene fluvial stratigraphy in northeastern Spain’s Ebro Basin can tell us about water discharge and sediment flux across distributive fluvial systems at a basin scale.  The Cenozoic stratigraphy of northeastern Spain’s triangular shaped Ebro Basin embodies a classic example of the formation of a closed sedimentary basin.  The Ebro Basin contains a number of remarkably well exposed fluvial sedimentary deposits.  These deposits outcrop as distinctive laterally contiguous channel sand bodies.  Clastic sediment supply in the Ebro Basin is largely governed by tectonic uplift and basin subsidence related to the Pyrenean orogen with peripheral contributions from the Catalan Coast and Iberian Ranges.  We test the idea that the record of conditions in the fluvial systems should reflect the record of lacustrine chemical sediments through sediment mass conservation.  In order to test this hypothesis measurements of bedform height, barform height, sediment size, and paleochannel dimensions were collected in the field.  Our paleohydraulic model uses previously derived theoretical and empirical relationships to recreate the conditions in these ancient fluvial systems.  These results are scaled up by accounting for drainage density and intermittency in order to address the principal question at a basin scale.  Paleodischarges from the fluvial sediments are comparable to those from river chemistry calculations for the lacustrine facies. </p>

scholarly journals Efficacy of bedrock erosion by subglacial water flow

2015 ◽  
Vol 3 (3) ◽  
pp. 849-908 ◽  
Author(s):  
F. Beaud ◽  
G. E. Flowers ◽  
J. G. Venditti
Keyword(s):  
Water Flow ◽  
Water Pressure ◽  
Water Discharge ◽  
Sediment Supply ◽  
Fluvial Systems ◽  
Glacial Meltwater ◽  
Erosion Rates ◽  
Subglacial Environment ◽  
Basin Scale ◽  
Bedrock Erosion

Abstract. Bedrock erosion by sediment-bearing subglacial water remains little-studied, however the process is thought to contribute to bedrock erosion rates in glaciated landscapes and is implicated in the excavation of tunnel valleys and the incision of inner gorges. We adapt physics-based models of fluvial abrasion to the subglacial environment, assembling the first model designed to quantify bedrock erosion caused by transient subglacial water flow. The subglacial drainage model consists of a one-dimensional network of cavities dynamically coupled to one or several Röthlisberger channels (R-channels). The bedrock erosion model is based on the tools and cover effect, whereby particles entrained by the flow impact exposed bedrock. We explore the dependency of glacial meltwater erosion on the structure and magnitude of water input to the system, the ice geometry and the sediment supply. We find that erosion is not a function of water discharge alone, but also depends on channel size, water pressure and on sediment supply, as in fluvial systems. Modelled glacial meltwater erosion rates are one to two orders of magnitude lower than the expected rates of total glacial erosion required to produce the sediment supply rates we impose, suggesting that glacial meltwater erosion is negligible at the basin scale. Nevertheless, due to the extreme localization of glacial meltwater erosion (at the base of R-channels), this process can carve bedrock (Nye) channels. In fact, our simulations suggest that the incision of bedrock channels several centimetres deep and a few meters wide can occur in a single year. Modelled incision rates indicate that subglacial water flow can gradually carve a tunnel valley and enhance the relief or even initiate the carving of an inner gorge.

scholarly journals Efficacy of bedrock erosion by subglacial water flow

2016 ◽  
Vol 4 (1) ◽  
pp. 125-145 ◽  
Author(s):  
F. Beaud ◽  
G. E. Flowers ◽  
J. G. Venditti
Keyword(s):  
Water Flow ◽  
Water Pressure ◽  
Water Discharge ◽  
Sediment Supply ◽  
Fluvial Systems ◽  
Glacial Meltwater ◽  
Erosion Rates ◽  
Subglacial Environment ◽  
Basin Scale ◽  
Bedrock Erosion

Abstract. Bedrock erosion by sediment-bearing subglacial water remains little-studied; however, the process is thought to contribute to bedrock erosion rates in glaciated landscapes and is implicated in the excavation of tunnel valleys and the incision of inner gorges. We adapt physics-based models of fluvial abrasion to the subglacial environment, assembling the first model designed to quantify bedrock erosion caused by transient subglacial water flow. The subglacial drainage model consists of a one-dimensional network of cavities dynamically coupled to one or several Röthlisberger channels (R-channels). The bedrock erosion model is based on the tools and cover effect, whereby particles entrained by the flow impact exposed bedrock. We explore the dependency of glacial meltwater erosion on the structure and magnitude of water input to the system, the ice geometry, and the sediment supply. We find that erosion is not a function of water discharge alone, but also depends on channel size, water pressure, and sediment supply, as in fluvial systems. Modelled glacial meltwater erosion rates are 1 to 2 orders of magnitude lower than the expected rates of total glacial erosion required to produce the sediment supply rates we impose, suggesting that glacial meltwater erosion is negligible at the basin scale. Nevertheless, due to the extreme localization of glacial meltwater erosion (at the base of R-channels), this process can carve bedrock (Nye) channels. In fact, our simulations suggest that the incision of bedrock channels several centimetres deep and a few metres wide can occur in a single year. Modelled incision rates indicate that subglacial water flow can gradually carve a tunnel valley and enhance the relief or even initiate the carving of an inner gorge.

Sediment slugs: large-scale fluctuations in fluvial sediment transport rates and storage volumes

1995 ◽  
Vol 19 (4) ◽  
pp. 500-519 ◽  
Author(s):  
A.P. Nicholas ◽  
P.J. Ashworth ◽  
M.J. Kirkby ◽  
M.G. Macklin ◽  
T. Murray
Keyword(s):  
Sediment Transport ◽  
Sediment Supply ◽  
Fluvial Systems ◽  
Event Scale ◽  
Fluvial Sediment ◽  
Sediment Routing ◽  
Basin Scale ◽  
Wide Range ◽  
And Storage ◽  
Fluvial Sediment Transport

Variations in fluvial sediment transport rates and storage volumes have been described previously as sediment waves or pulses. These features have been identified over a wide range of temporal and spatial scales and have been categorized using existing bedform classifications. Here we describe the factors controlling the generation and propagation of what we term sediment slugs. These can be defined as bodies of clastic material associated with disequilibrium conditions in fluvial systems over time periods above the event scale. Slugs range in magnitude from unit bars (Smith, 1974) up to sedimentary features generated by basin-scale sediment supply disturbances (Trimble, 1981). At lower slug magnitudes, perturbations in sediment transport are generated by local riverbank and/or bed erosion. Larger-scale features result from the occurrence of rare high- magnitude geomorphic events, and the impacts on water and sediment production of tectonics, glaciation, climate change and anthropogenic influences. Simple sediment routing functions are presented which may be used to describe the propagation of sediment slugs in fluvial systems. Attention is drawn to components of the fluvial system where future research is urgently required to improve our quantitative understanding of drainage-basin sediment dynamics.

scholarly journals Estimating River Sediment Discharge in the Upper Mississippi River Using Landsat Imagery

2020 ◽  
Vol 12 (15) ◽  
pp. 2370
Author(s):  
Jonathan A. Flores ◽  
Joan Q. Wu ◽  
Claudio O. Stöckle ◽  
Robert P. Ewing ◽  
Xiao Yang
Keyword(s):  
Mississippi River ◽  
Landsat Imagery ◽  
Water Discharge ◽  
Absolute Error ◽  
Sediment Concentration ◽  
Hydraulic Geometry ◽  
Upper Mississippi River ◽  
Sediment Discharge ◽  
River Channels ◽  
Fluvial Systems

With the decline of operational river gauges monitoring sediments, a viable means of quantifying sediment transport is needed. In this study, we address this issue by applying relationships between hydraulic geometry of river channels, water discharge, water-leaving surface reflectance (SR), and suspended sediment concentration (SSC) to quantify sediment discharge with the aid of space-based observations. We examined 5490 Landsat scenes to estimate water discharge, SSC, and sediment discharge for the period from 1984 to 2017 at nine gauging sites along the Upper Mississippi River. We used recent advances in remote sensing of fluvial systems, such as automated river width extraction, Bayesian discharge inference with at-many-stations hydraulic geometry (AMHG), and SSC-SR regression models. With 621 Landsat scenes available from all the gauging sites, the results showed that the water discharge and SSC retrieval from Landsat imagery can yield reasonable sediment discharge estimates along the Upper Mississippi River. An overall relative bias of −25.4, mean absolute error (MAE) of 6.24 × 104 tonne/day, relative root mean square error (RRMSE) of 1.21, and Nash–Sutcliffe Efficiency (NSE) of 0.49 were obtained for the sediment discharge estimation. Based on these statistical metrics, we identified three of the nine gauging sites (St. Louis, MO; Chester, IL; and Thebes, IL), which were in the downstream portion of the river, to be the best locations for estimating water and sediment discharge using Landsat imagery.

How do river channels aggrade? An investigation into the importance of upstream drivers (water discharge and sediment supply) on sediment aggradation using analogue modelling

2020 ◽  
Author(s):  
Stephen E. Watkins ◽  
Nikhil Sharma ◽  
Luis Valero ◽  
Maxime Tremblin ◽  
Abdallah S. Zaki ◽  
...  
Keyword(s):  
Sea Level ◽  
Environmental Changes ◽  
Water Discharge ◽  
Scale Up ◽  
Sediment Supply ◽  
River Channels ◽  
Fluvial System ◽  
Fluvial Deposits ◽  
Analogue Modelling ◽  
Stratigraphic Architecture

<p><span>Stratigraphic architecture of fluvial deposits is often interpreted as a record of changes in accommodation created by absolute sea-level change, subsidence, or a combination of both (downstream drivers). An increase or decrease in accommodation causes the fluvial system to respond by either aggrading or degrading to a new equilibrium slope. However, in recent years the role of upstream drivers, such as water discharge and sediment supply (volume and grain-size distribution), in controlling equilibrium slopes has gained more importance, however we still lack significant understanding of these upstream processes. It is important to be able to differentiate between stratigraphy influenced by upstream and downstream drivers in the field because fluvial deposits represent an important archive of environmental changes.  Traditionally, downstream drivers are often invoked to explain past accommodation changes, but in actuality there are rarely robust constraints on the cause of these space changes. At present there is still no well-documented examples of upstream versus downstream driven stratigraphic architecture. One way to address this issue is by undertaking analogue modelling (i.e. flume experiments) as this permits the isolation of individual parameters, such as water discharge, and allows us to investigate their role on the fluvial system in a controlled environment. </span></p><p><span> </span></p><p><span>In the first part of the project that we present here, we investigate how sediment aggradation within a channel develops through time by using a quasi-2D flume.  We have designed and manufactured a narrow (0.05 m), long (2.4 m) flume with an initial gradient of zero.  We aim to (i) investigate how aggradation occurs through time using a series of different water discharges, sediment supplies and sediment concentrations and observe the resulting equilibrium slopes; (ii) perturb the system once equilibrium is reached to observe the readjustment of the system to new conditions; (iii) carry out a series of experiments varying downstream drivers (i.e. sea-level) which theoretically produce the same amount of aggradation as the upstream parameters we have used do, we will then be able to compare any similarities or differences in stratigraphy.  Ultimately we will use these results to scale up to a fully three-dimensional analogue model (i.e. a wide flume, approximately 1 m) that produces channels and floodplains.  We can then investigate how the upstream and downstream changes seen in the narrow flume are translated into the wider flume.</span></p>

scholarly journals Alluvial channel response to environmental perturbations: fill-terrace formation and sediment-signal disruption

2019 ◽  
Vol 7 (2) ◽  
pp. 609-631 ◽  
Author(s):  
Stefanie Tofelde ◽  
Sara Savi ◽  
Andrew D. Wickert ◽  
Aaron Bufe ◽  
Taylor F. Schildgen
Keyword(s):  
Water Discharge ◽  
Sediment Supply ◽  
Fluvial Systems ◽  
Fluvial Terraces ◽  
Base Level ◽  
Environmental Perturbations ◽  
Alluvial Channel ◽  
Channel Slope ◽  
Lag Times ◽  
Sediment Export

Abstract. The sensitivity of fluvial systems to tectonic and climatic boundary conditions allows us to use the geomorphic and stratigraphic records as quantitative archives of past climatic and tectonic conditions. Thus, fluvial terraces that form on alluvial fans and floodplains as well as the rate of sediment export to oceanic and continental basins are commonly used to reconstruct paleoenvironments. However, we currently lack a systematic and quantitative understanding of the transient evolution of fluvial systems and their associated sediment storage and release in response to changes in base level, water input, and sediment input. Such knowledge is necessary to quantify past environmental change from terrace records or sedimentary deposits and to disentangle the multiple possible causes for terrace formation and sediment deposition. Here, we use a set of seven physical experiments to explore terrace formation and sediment export from a single, braided channel that is perturbed by changes in upstream water discharge or sediment supply, or through downstream base-level fall. Each perturbation differently affects (1) the geometry of terraces and channels, (2) the timing of terrace cutting, and (3) the transient response of sediment export from the basin. In general, an increase in water discharge leads to near-instantaneous channel incision across the entire fluvial system and consequent local terrace cutting, thus preserving the initial channel slope on terrace surfaces, and it also produces a transient increase in sediment export from the system. In contrast, a decreased upstream sediment-supply rate may result in longer lag times before terrace cutting, leading to terrace slopes that differ from the initial channel slope, and also lagged responses in sediment export. Finally, downstream base-level fall triggers the upstream propagation of a diffuse knickzone, forming terraces with upstream-decreasing ages. The slope of terraces triggered by base-level fall mimics that of the newly adjusted active channel, whereas slopes of terraces triggered by a decrease in upstream sediment discharge or an increase in upstream water discharge are steeper compared to the new equilibrium channel. By combining fill-terrace records with constraints on sediment export, we can distinguish among environmental perturbations that would otherwise remain unresolved when using just one of these records.

The upper cenozoic evolution of the Duero and Ebro fluvial systems (N-Spain): part I. paleogeography; part II. geomorphology

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
Daniel Mikeš
Keyword(s):  
Sedimentary Basins ◽  
Ebro Basin ◽  
Fluvial Systems ◽  
Isostatic Rebound ◽  
Field Evidence ◽  
Upper Cenozoic ◽  
Knick Point ◽  
Cenozoic Sediments

AbstractLack of age dates in the terrigenous Cenozoic sediments of the Duero and the Ebro sedimentary basins has complicated tecto-stratic correlation across the two basins. We tentatively synthesize a range of existing studies and new data to construct a rough general paleogeography throughout Upper Cenozoic times. The more extensive erosion of the Ebro has been previously attributed to the earlier moment of opening. We tentatively analyse lithostratic data to conclude that the lower knick-point and different lithologies have also contributed to the deeper erosion in the Ebro Basin. We conclude from lithostratic data and field evidence that the W half of the Rioja was part of the Duero in earlier times and that the escarpment retreated westward through the Rioja in four subsequent episodes of erosion. The tilt of the NW Duero is a consequence of isostatic rebound to this erosion.

Middle Holocene environmental reconstruction and climatic inferences through multi-proxy records from Seymareh lake sediments (Zagros Mts., Iran)

2021 ◽  
Author(s):  
Michele Delchiaro ◽  
Giulia Iacobucci ◽  
Francesco Troiani ◽  
Marta Della Seta ◽  
Paolo Ballato ◽  
...  
Keyword(s):  
Sedimentation Rate ◽  
Water Discharge ◽  
Sediment Supply ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
The Holocene ◽  
Middle Holocene ◽  
Lake System ◽  
Proxy Records ◽  
The Impact

<p>The Seymareh landslide is the largest rock slope failure (44 Gm<sup>3</sup>) ever recorded on the exposed Earth surface. It detached ∼10 ka BP from the northeastern flank of the Kabir-Kuh anticline (Zagros Mts., Iran) originating the natural dam responsible for the formation of a three-lake system (Seymareh, Jaidar, and Balmak lakes, with an area of 259, 46, and 5 km<sup>2</sup>, respectively). The lake system persisted for ∼3000 yr during the Holocene before its emptying phase due to overflow. A sedimentation rate of 21 mm yr<sup>−1</sup> was estimated for the Seymareh lacustrine deposits, which increased during the early stage of lake emptying because of enhanced sediment yield from the lake tributaries. </p><p>To reconstruct the climatic and environmental impact on the lake infilling, we reviewed the geomorphology of the basins and combined the results with multi-proxy records from a 30 m thick lacustrine sequence in Seymareh Lake. Major analyses comprise grain size analysis, carbon and oxygen stable isotopes of carbonate-bearing sediments, and X-ray diffraction analysis of clay minerals.</p><p>Lake overflowing is largely accepted as the main response to variations in water discharge and sediment supply since the alternation from dry to wet phases enhances sediment mobilization along hillslopes decreasing the accommodation space in the downstream sedimentary basins. In this regard, during the early-middle Holocene, the Seymareh area, as well as the entire Middle East, was affected by short-term climate changes at the millennial-scale, as testified by both paleoecological and archaeological evidence. Indeed, several records from Iranian lakes (i.e., Mirabad, Zeribar, Urmia) well documented the temperature and the moisture conditions of the western Zagros Mountains during the Holocene. During the early Holocene, the precipitation remained low up to 6 ka BP, reaching the driest condition around 8-8.2 ka BP. The impact of this abrupt climate change is evident across West Asia, where the first large villages with domesticated cereals and sheeps disappeared, converting to small hamlets and starting habitat-tracking. As regards the Seymareh area, a more irregular distribution of rainfalls and their increasing seasonality may support rhexistasy conditions, during which the scarce vegetation cover enhances both the hillslope erosion and sedimentation rate in the basins, most likely contributing to the overflow of Seymareh Lake. </p>

Feasibility of sedimentation strategies for the Mekong delta to counterbalance relative sea-level rise

2021 ◽  
Author(s):  
Frances E. Dunn ◽  
Philip S. J. Minderhoud
Keyword(s):  
Land Use ◽  
Sea Level Rise ◽  
Sea Level ◽  
Mekong Delta ◽  
Sediment Deposition ◽  
Sediment Supply ◽  
Sediment Flux ◽  
Relative Sea Level ◽  
Fluvial Sediment ◽  
Relative Sea Level Rise

<p>As one of the largest deltas in the world, the Mekong delta is home to over 17 million people and supports internationally important agriculture. Recently deposited sediment compacts and causes subsidence in deltas, so they require regular sediment input to maintain elevation relative to sea level. These processes are complicated by human activities, which prevent sediment deposition indirectly through reducing fluvial sediment supply and directly through the construction of flood defence infrastructure on deltas, impeding floods which deliver sediment to the land. Additionally, anthropogenic activities increase the rate of subsidence through the extraction of groundwater and other land-use practices.</p><p>This research shows the potential for fluvial sediment delivery to compensate for sea-level rise and subsidence in the Mekong delta over the 21st century. We use detailed elevation data and subsidence scenarios in combination with regional sea-level rise and fluvial sediment flux projections to quantify the potential for maintaining elevation relative to sea level in the Mekong delta. We present four examples of localised sedimentation scenarios in specific areas, for which we quantified the potential effectiveness of fluvial sediment deposition for offsetting relative sea-level rise. The presented sediment-based adaptation strategies are complicated by existing land use, therefore a change in water and sediment management is required to effectively use natural resources and employ these adaptation methods. The presented approach could be an exemplar to assess sedimentation strategy feasibility in other delta systems worldwide that are under threat from sea-level rise.</p>

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