scholarly journals Experimental migration of knickpoints: influence of style of base-level fall and bed lithology

2016 ◽  
Vol 4 (1) ◽  
pp. 11-23 ◽  
Author(s):  
J.-L. Grimaud ◽  
C. Paola ◽  
V. Voller
Keyword(s):  
Fall Rate ◽  
Pool Depth ◽  
Similar Shape ◽  
Base Level ◽  
Self Organized ◽  
Plunge Pool ◽  
Source To Sink ◽  
Constant Rate ◽  
Geomorphic Features ◽  
River Profiles

Abstract. Knickpoints are fascinating and common geomorphic features whose dynamics influence the development of landscapes and source-to-sink systems – in particular the upstream propagation of erosion. Here, we study river profiles and associated knickpoints experimentally in a microflume filled with a cohesive substrate made of silica, water and kaolinite. We focus on the effect on knickpoint dynamics of varying the distribution of base-level fall (rate, increment, and period) and substrate strength, i.e., kaolinite content. Such simple cases are directly comparable to both bedrock and alluvial river systems. Under a constant rate of base-level fall, knickpoints of similar shape are periodically generated, highlighting self-organized dynamics in which steady forcing leads to multiple knickpoint events. Temporary shielding of the bed by alluvium controls the spacing between these unit knickpoints. Shielding is, however, not effective when base-level drops exceed alluvium thickness. While the base-level fall rate controls the overall slope of experiments, it is not instrumental in dictating the major characteristics of unit knickpoints. Instead the velocity, face slope and associated plunge pool depth of these knickpoints are all strongly influenced by lithology. The period between knickpoints is set by both alluvium thickness and base-level fall rate, allowing use of knickpoint spacing along rivers as an indicator of base-level fall rate.

scholarly journals Experimental migration of knickpoints: influence of style of base-level fall and bed lithology

2015 ◽  
Vol 3 (3) ◽  
pp. 773-805 ◽  
Author(s):  
J.-L. Grimaud ◽  
C. Paola ◽  
V. Voller
Keyword(s):  
Fall Rate ◽  
Pool Depth ◽  
Similar Shape ◽  
Base Level ◽  
Self Organized ◽  
Plunge Pool ◽  
Source To Sink ◽  
Constant Rate ◽  
Geomorphic Features ◽  
River Profiles

Abstract. Knickpoints are fascinating and common geomorphic features whose dynamics influences the development of landscapes and source-to-sink systems – in particular the upstream propagation of erosion. Here, we study river profiles and associated knickpoints experimentally in a micro flume filled with a cohesive substrate made of silica, water and kaolinite. We focus on the effect on knickpoint dynamics of varying the distribution of base-level fall (rate, increment, and period) and substrate strength, i.e. kaolinite content. Such simple cases are directly comparable to both bedrock and alluvial river systems. Under a constant rate of base-level fall, knickpoints of similar shape are periodically generated, highlighting a self-organized dynamics in which steady forcing leads to multiple knickpoint events. Temporary shielding of the bed by alluvium controls the spacing between these unit knickpoints. Shielding is however not effective when base-level drops exceed alluvium thickness. While the base-level fall rate controls the overall slope of experiments, it is not instrumental in dictating the major characteristics of unit knickpoints. Instead the velocity, face slope and associated plunge pool depth of these knickpoints are all strongly influenced by lithology. The period between knickpoints is set by both alluvium thickness and base-level fall rate, allowing use of knickpoint spacing along rivers as an indicator of base-level fall rate.

Evaluating the effect of variable lithologies on rates of knickpoint migration in the Wutach catchment, southern Germany

2020 ◽  
Author(s):  
Andreas Ludwig ◽  
Wolfgang Schwanghart ◽  
Florian Kober ◽  
Angela Landgraf
Keyword(s):  
Transient Response ◽  
Stream Power ◽  
Main Trunk ◽  
Southern Germany ◽  
Level Change ◽  
Base Level ◽  
Bulk Parameter ◽  
River Profiles ◽  
Topographic Evolution ◽  
Headward Erosion

<p>The topographic evolution of landscapes strongly depends on the resistance of bedrock to erosion. Detachment-limited fluvial landscapes are commonly analyzed and modelled with the stream power incision model (SPIM) which parametrizes erosional efficiency by the bulk parameter K whose value is largely determined by bedrock erodibility. Inversion of the SPIM using longitudinal river profiles enables resolving values of K if histories of rock-uplift or base level change are known. Here, we present an approach to estimate K-values for the Wutach catchment, southern Germany. The catchment is a prominent example of river piracy that occurred ~18 ka ago as response to headward erosion of a tributary to the Rhine. Base level fall of up to 170 m triggered a wave of upstream migrating knickpoints that represent markers for the transient response of the landscape. Knickpoint migration along the main trunk stream and its tributaries passed different lithological settings, which allows us to estimate K for crystalline and sedimentary bedrock units of variable erodibility.</p>

scholarly journals Quantifying Normal Fault Evolution from River Profile Analysis in the Northern Basin and Range Province, Southwest Montana, USA

Lithosphere ◽  
2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Ian P. Armstrong ◽  
Brian J. Yanites ◽  
Nate Mitchell ◽  
Clarke DeLisle ◽  
Bruce J. Douglas
Keyword(s):  
Normal Fault ◽  
Basin And Range ◽  
Fault Slip ◽  
Stream Power ◽  
Spatial And Temporal Patterns ◽  
Basin And Range Province ◽  
Slip Rates ◽  
Base Level ◽  
River Profiles ◽  
Fault Evolution

Abstract Over the past few decades, tectonic geomorphology has been widely implemented to constrain spatial and temporal patterns of fault slip, especially where existing geologic or geodetic data are poor. We apply this practice along the eastern margin of Bull Mountain, Southwest Montana, where 15 transient channels are eroding into the flat, upstream relict landscape in response to an ongoing period of increased base level fall along the Western North Boulder fault. We aim to improve constraints on the spatial and temporal slip rates across the Western North Boulder fault zone by applying channel morphometrics, cosmogenic erosion rates, bedrock characteristics, and calibrated reproductions of the modern river profiles using a 1-dimensional stream power incision model that undergoes a change in the rate of base level fall. We perform over 104 base level fall simulations to explore a wide range of fault slip dynamics and stream power parameters. Our best fit simulations suggest that the Western North Boulder fault started as individual fault segments along the middle to southern regions of Bull Mountain that nucleated around 6.2 to 2.5 Ma, respectively. This was followed by the nucleation of fault segments in the northern region around 1.5 to 0.4 Ma. We recreate the evolution of the Western North Boulder fault to show that through time, these individual segments propagate at the fault tips and link together to span over 40 km, with a maximum slip of 462 m in the central portion of the fault. Fault slip rates range from 0.02 to 0.45 mm/yr along strike and are consistent with estimates for other active faults in the region. We find that the timing of fault initiation coincides well with the migration of the Yellowstone hotspot across the nearby Idaho-Montana border and thus attribute the initiation of extension to the crustal bulge from the migrating hotspot. Overall, we provide the first quantitative constraints on fault initiation and evolution of the Western North Boulder fault, perhaps the farthest north basin in the Northern Basin and Range province that such constraints exist. We show that river profiles are powerful tools for documenting the spatial and temporal patterns of normal fault evolution, especially where other geologic/geodetic methods are limited, proving to be a vital tool for accurate tectonic hazard assessments.

Uplift and growth of the northwest Pamir

2021 ◽  
Author(s):  
Edward R. Sobel ◽  
Rasmus Thiede ◽  
Paolo Ballato ◽  
Konstanze Stübner ◽  
Jonas Kley ◽  
...  
Keyword(s):  
Sedimentary Cover ◽  
Hanging Wall ◽  
Foreland Basin ◽  
High Elevation ◽  
The Tibetan Plateau ◽  
Base Level ◽  
River Profiles ◽  
Geodynamic Models ◽  
Uplift And Erosion ◽  
The Impact

<p>The Pamir forms the northwestern tail of the Tibetan plateau and is a first-order tectonic feature of the Cenozoic Indo-Eurasian collision. The nature of the topographic uplift and orogenic growth of the entire northwestern margin of the Pamir is poorly constrained; however, this history can provide important constraints that are required to test geodynamic models of the tectonic evolution of the Pamir. Here we focus on the uplift history of the western and northwestern unglaciated margin of the Northern Pamir, the Darvaz and the Peter-the-First Ranges. These three ranges were formed by three major fault systems: the Main Pamir Thrust (MPT), the Darvaz and the Vakhsh fault zones (DFZ, VFZ). To assess the impact of tectonic uplift on the geomorphic evolution, we analyzed geomorphic characteristics of the topography, the longitudinal river profiles and the relief. To better constrain the regional crustal cooling history and uplift, we obtained thermochronologic cooling ages from the three regions.</p><p>We present 19 new zircon (U-Th-Sm)/He (ZHe) ages, 7 apatite fission track (AFT) ages, and 4 apatite (U-Th-Sm)/He (AHe) ages, ranging between >200 and 4 Ma, 14 and 4 Ma, and 15 and 3 Ma, respectively. The three units are characterized by unique Neogene cooling pathways, suggesting that they exhumed independently.</p><p>We discovered extensive low-relief landscapes with Neogene sedimentary cover uplifted ~2 km in elevation above the present-day regional base level. Our analysis indicates that the Panj and Vakhsh rivers form the regional base levels for the river network draining the entire northern and western margin of the Pamir. In the hanging wall of DFZ, the Paleozoic bedrock is characterized by significant relief (>1 km), the Neogene cover onlaps directly onto this Paleozoic bedrock. The tributary rivers crossing these landscapes are characterized by gentle, concave upstream longitudinal profiles at high elevation. These are interrupted by major knickpoint zones and steep downstream segments draining towards the deeply incised Panj and Vakhsh rivers. This indicates that the Darvaz Fault hanging wall had been uplifted and eroded prior to deposition of upper Neogene sediments, suggesting that the DFZ has a prolonged Neogene slip history. In contrast to the northeastern Pamir, here, the MPT-hanging-wall is characterized by reset late Oligocene-Early Miocene ZHe cooling ages ranging between 26 and 17 Ma. AFT and AHe-ages between 15 and 13 Ma suggest that exhumation suddenly terminated during the middle Miocene. In contrast, Jurassic sandstones exposed near the DFZ yield mostly un-reset Triassic-Jurassic ZHe ages (~250-170 Ma), a reset AFT age of ~5 Ma and a 2.5 Ma AHe age. Within the Peter-the-1st-Range, we obtained fully reset ~ 5 Ma ZHe ages, and ~4 Ma AFT ages. The rapid cooling trends since at least ~5 Ma suggest that deformation and a significant portion of crustal shortening propagated into the Tadjik foreland basin, causing enhanced uplift and erosion of the hanging wall of the VFZ and related faults. This deformation triggered ~2 km uplift of the entire northwest Pamir, recorded in uplifted paleo-landscapes and dissected tributaries of the Panj and Vakhsh rivers.</p>

Linking source to stratigraphy through sediment transport: The importance of spatially variable climate on the evolution of the Argentine Andes

2020 ◽  
Author(s):  
Rebekah Harries ◽  
Linda Kirstein ◽  
Alex Whittaker ◽  
Mikael Attal ◽  
Boris Gailleton ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Geomorphic Mapping ◽  
Mountain Ranges ◽  
Base Level ◽  
Source Regions ◽  
Sediment Deposits ◽  
Mountain Front ◽  
History Of ◽  
River Profiles ◽  
Sediment Export

<p>Over geological timescales, we often assume the export of sediment, from mountainous source regions to depositional basins, is relatively instantaneous. As such, stratigraphic units are thought to capture erosional trends in their upstream catchment. The export of sediment from mountain basins, however, is a process heavily modified by sediment transport.</p><p>Here, we exploit a well-constrained field site in the Argentine Andes to demonstrate how the connectivity between hillslopes and mountain rivers modulates long-term sediment export in post glacial landscapes. We map out erosion trends in upstream catchments by combining an analysis of river profiles with geomorphic mapping of sediment deposits. We then use a comprehensive catalogue of clast lithology data to test to what extent upstream erosion trends are recorded downstream.</p><p>Despite their proximity to each other, we find adjacent catchments supplying sediment to the Iglesia basin have distinctly different degrees of hillslope-river connectivity, evident from the morphology of terraced and fan deposits within the catchments. Catchments with good hillslope-river channel connectivity also have a higher abundance of clasts sourced from the upper cordillera downstream of their mountain front. We place these observations within the context of a strong precipitation gradient across the cordillera and demonstrate the importance of climate and climate-controlled base-level on the spatial distribution of erosion within mountain catchments and fundamentally, on sediment export.</p><p>This work has implications for those using gravels to reconstruct the history of mountain ranges. Furthermore, it highlights the need to better constrain the potential for a disproportionate increase in sediment export to populated areas under future climate scenarios</p>

scholarly journals Valley downcutting in the Ardennes (W Europe): Interplay between tectonically triggered regressive erosion and climatic cyclicity

2012 ◽  
Vol 91 (1-2) ◽  
pp. 79-90 ◽  
Author(s):  
A. Demoulin ◽  
A. Becker ◽  
G. Rixhon ◽  
R. Braucher ◽  
D. Bourlès ◽  
...  
Keyword(s):  
Common Belief ◽  
Migration Rates ◽  
Base Level ◽  
River Incision ◽  
New Findings ◽  
Starting Point ◽  
Middle Europe ◽  
The Common ◽  
Vertical Spacing ◽  
River Profiles

AbstractWhile climatic models of valley downcutting discuss the origin of terrace staircases in valleys of middle Europe within the frame of alternating cold and temperate periods of the Quaternary, other models, starting from a base level fall imposed by an initial tectonic signal, describe the response of the drainage network mainly as the propagation of an erosion wave from the place of base level fall (the margin of the uplifted region) toward the headwaters, the two types of model being rarely confronted. In the Ardennes (West Europe), cosmogenic 10Be and 26Al ages have recently been calculated for the abandonment of the Younger Main Terrace (YMT) level, a prominent feature at mid-height of the valleysides marking the starting point of the mid-Pleistocene phase of deep river incision in the massif. These ages show that the terrace has been abandoned diachronically as the result of a migrating erosion wave that started at 0.73 Ma in the Meuse catchment just north of the massif, soon entered the latter, and is still visible in the current long profiles of the Ardennian Ourthe tributaries as knickpoints disturbing their upper reaches. At first glance, these new findings are incompatible with the common belief that the terraces of the Ardennian rivers were generated by a climatically triggered stepwise general incision of the river profiles. However, several details of the terrace staircases (larger than average vertical spacing between the YMT and the next younger terrace, varying number of post-YMT terraces in trunk stream, tributaries and subtributaries) show that a combination of the climatic and tectonic models of river incision is able to satisfactorily account for all available data. The cosmogenic ages of the YMT also point out a particular behaviour of the migrating knickpoints, which apparently propagated on average more slowly in the main rivers than in the tributaries, in contradiction with the relation that makes knickpoint celerity depend directly on drainage area. We tentatively suggest a process accounting for such anomalies in migration rates.

Signal propagation in sediment routing systems: an application for granulates prediction (location, grain-size)

2020 ◽  
Author(s):  
Francois Guillocheau ◽  
Cécile Robin
Keyword(s):  
Sedimentary Basins ◽  
Signal Propagation ◽  
Transfer Of Knowledge ◽  
Base Level ◽  
Erosion Processes ◽  
Sediment Routing ◽  
Source To Sink ◽  
Solute Fluxes ◽  
Working Together ◽  
Armorican Massif

<p>The consideration of entire “Source to Sink" systems is one of the most recent and challenging advances in earth surface dynamics and sedimentary geology. To understand S2S systems it is necessary to enhance sharing of knowledge and concepts between (1) geomorphology, which focuses on the understanding of erosion processes driving landform evolution and sediment fluxes, (2) stratigraphy/sedimentology, which focuses on the nature of sedimentary deposits and their distribution in time and space, and (3) tectonics and structural geology, which set the dimensions, geometry and dynamics of source/transfer areas and sedimentary basins (the sink). Understanding S2S systems also involves other Geosciences disciplines such as paleoclimatology and geochemistry, because they allow quantifying the factors controlling S2S systems dynamics (climatic controls on erosion, solid vs. solute fluxes, etc.).</p><p>The main challenges are (1) to get all the above mentioned disciplines working together on geological or numerical approaches of the whole S2S system, in different tectonic and climatic settings and (2) to convince some industries of the merits of this approach, e.g. industries dealing with geothermy or granulates.</p><p>We here present one example of academia – industry transfer of knowledge for granulates: the low accommodation alluvial system of the Armorican Massif of Messinian to Pliocene age, major source of granulates for the development of the Brittany Province (western France). The understanding of the base level fluctuations sensuWheeler (1964), joined to an knowledge of the uplift history, the climate variations, and the source of sediments (Eocene laterite profiles) gave tools for a better prediction on the location and quality of the granulates.</p>

scholarly journals Origin of Knickpoints in an Alpine Context Subject to Different Perturbing Factors, Stura Valley, Maritime Alps (North-Western Italy)

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 443 ◽  
Author(s):  
Monica Marrucci ◽  
Gerold Zeilinger ◽  
Adriano Ribolini ◽  
Wolfgang Schwanghart
Keyword(s):  
River Networks ◽  
River Channels ◽  
Maritime Alps ◽  
Factors Affecting ◽  
Base Level ◽  
Longitudinal Profiles ◽  
River Profiles ◽  
North Western ◽  
Geomorphological Features ◽  
Tectonic Movements

Natural catchments are likely to show the existence of knickpoints in their river networks. The origin and genesis of the knickpoints can be manifold, considering that the present morphology is the result of the interactions of different factors such as tectonic movements, quaternary glaciations, river captures, variable lithology, and base-level changes. We analyzed the longitudinal profiles of the river channels in the Stura di Demonte Valley (Maritime Alps) to identify the knickpoints of such an alpine setting and to characterize their origins. The distribution and the geometry of stream profiles were used to identify the possible causes of the changes in stream gradients and to define zones with genetically linked knickpoints. Knickpoints are key geomorphological features for reconstructing the evolution of fluvial dissected basins, when the different perturbing factors affecting the ideally graded fluvial system have been detected. This study shows that even in a regionally small area, perturbations of river profiles are caused by multiple factors. Thus, attributing (automatically)-extracted knickpoints solely to one factor, can potentially lead to incomplete interpretations of catchment evolution.

scholarly journals Self-Organized Fast Routing Protocol for Radial Underwater Networks

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4178 ◽  
Author(s):  
Waheeduddin Hyder ◽  
Javier Poncela ◽  
Miguel-Angel Luque ◽  
Pablo Otero
Keyword(s):  
Routing Protocol ◽  
Acoustic Waves ◽  
Energy Efficient ◽  
Propagation Speed ◽  
Angle Of Arrival ◽  
Gateway Node ◽  
Self Organized ◽  
Proactive Routing ◽  
Source To Sink ◽  
Monitoring And Surveillance

An underwater wireless sensor networks (UWSNs) is an emerging technology for environmental monitoring and surveillance. One of the side effects of the low propagation speed of acoustic waves is that routing protocols of terrestrial wireless networks are not applicable. To address this problem, routing strategies focused on different aspects have been proposed: location free, location based, opportunistic, cluster based, energy efficient, etc. These mechanisms usually require measuring additional parameters, such as the angle of arrival of the signal or the depth of the node, which makes them less efficient in terms of energy conservation. In this paper, we propose a cross-layer proactive routing initialization mechanism that does not require additional measurements and, at the same time, is energy efficient. The algorithm is designed to recreate a radial topology with a gateway node, such that packets always use the shortest possible path from source to sink, thus minimizing consumed energy. Collisions are avoided as much as possible during the path initialization. The algorithm is suitable for 2D or 3D areas, and automatically adapts to a varying number of nodes, allowing one to expand or decrease the networked volume easily.

Source-to-sink system and its sedimentary records in the continental rift basins: An example from the Paleogene in the Bohai Sea Area, China

2017 ◽  
Vol 5 (4) ◽  
pp. ST35-ST51 ◽  
Author(s):  
Changgui Xu ◽  
Xiaofeng Du ◽  
Hongtao Zhu ◽  
Donghui Jia ◽  
Wei Xu ◽  
...  
Keyword(s):  
Bohai Sea ◽  
Steep Slope ◽  
Continental Rift ◽  
Gentle Slope ◽  
The Bohai Sea ◽  
Base Level ◽  
Source To Sink ◽  
Coupling System ◽  
Sea Area ◽  
Valley Type

The “source-to-sink” concept originated in the study of global change and atmospheric pollution. In recent years, the concept of a source-to-sink system has been widely applied in continental margin sedimentary analysis. In our research, the idea of source-to-sink is applied to the continental rift basin sedimentary system in the Bohai Sea area. The idea emphasizes that the sedimentation dynamics, including erosion, transportation, and accumulation, are considered as a complete source-to-sink system. The sand-rich region often corresponds to a source-to-sink coupling system in a complex continental rift basin, which includes the effective provenance, high-efficiency routing system, and base-level transition. In addition, (1) the effective provenance can be subdivided into explicit and implicit provenance systems in which the implicit provenance system has been shown to be a significant advancement in reservoir prediction for the Bohai Sea area, (2) the sediment-transport pathways and slope-break zone constitute the routing systems, and (3) the base-level transition is one of the allogenic factors that controls the position of the sandstone distribution in a sequence. Based on a large number of previous studies and different characteristics of sequence-stratigraphic models in the Bohai Sea area, we have evaluated three types of source-to-sink systems, including the fault-steep slope, strike-slip fault slope, and gentle slope pattern. In addition, the fault-steep-slope source-to-sink coupling system can be further subdivided into four types, namely, the corner, relay ramps, fault-throw diminishment-type, and valley-type source-to-sink systems. The source-to-sink system of the gentle slope pattern includes the uplift axis valley-type source-to-sink system and the slope-valley-type source-to-sink system. A small-scale, thick layer of fan delta is formed in the fault-steep-slope zone. A continuous braided river delta is formed in the strike-slip fault slope zone. A large-scale, thin layer of braided river delta is formed in the gentle slope zone. The characteristics of source-to-sink systems in continental rift basins are established for the exploration or prediction of favorable zones in the study area, as well as in similar basins.

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