scholarly journals Morphodynamic limits to environmental signal propagation across landscapes and into strata

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Stephan C. Toby ◽  
Robert A. Duller ◽  
Silvio De Angelis ◽  
Kyle M. Straub
Keyword(s):  
Signal Propagation ◽  
Sediment Flux ◽  
Scale Analysis ◽  
Field Scale ◽  
Short Term ◽  
Environmental Forcing ◽  
Environmental Signals ◽  
Sediment Routing ◽  
Environmental Signal ◽  
Landscape Response

AbstractThe sedimentary record contains unique information about landscape response to environmental forcing at timescales that far exceed landscape observations over human timescales. However, stochastic processes can overprint and shred evidence of environmental signals, such as sediment flux signals, and so inhibit their transfer to strata. Our community currently lacks a quantitative framework to differentiate between environmental signals and autogenic signals in field-scale analysis of strata. Here we develop a framework and workflow to estimate autogenic thresholds for ancient sediment routing systems. Crucially these thresholds can be approximated using measurements that are readily attainable from field systems, circumventing the low temporal resolution offered by strata. This work demonstrates how short-term system dynamics can be accessed from ancient sediment routing systems to place morphodynamic limits on environmental signal propagation across ancient landscapes and into strata.

Quantifying environmental signal propagation and preservation in ancient sediment routing systems using field data

2021 ◽  
Author(s):  
Robert Duller ◽  
Stephan Toby ◽  
Silvio De Angelis ◽  
Kyle Straub
Keyword(s):  
Temporal Resolution ◽  
Numerical Models ◽  
Signal Propagation ◽  
Sediment Flux ◽  
Threshold Condition ◽  
Environmental Signals ◽  
Sediment Routing ◽  
Environmental Signal ◽  
Spatio Temporal

<p>The assertion that stratigraphy will store environmental signals, such as sediment flux signals related to paleoclimate and tectonics, is debatable because that same stratigraphy can also store signals of autogenic processes that overprint and replace allogenic signals (“shred”). To establish the likelihood that strata will contain allogenic signals, the focus should be on quantifying autogenic processes. Models show that stratigraphic storage of allogenic sediment flux signals will only take place if it exceeds a threshold condition set by autogenic processes. This is supported by experimental and numerical models but its validation is hindered by low spatio-temporal resolution of stratigraphic datasets. We address this by reformulating a theoretical framework that dispenses with the need for exquisite temporal resolution. To demonstrate the applicability of our approach we explore the potential for environmental signal propagation and preservation in two ancient field systems: a small Pleistocene delta in Greece and a larger Eocene sediment routing system in the Spanish Pyrenees. This work demonstrates how short-term system dynamics can be integrated with long-term basin dynamics to provide a framework that assesses the capacity of sedimentary systems to store environmental signals.</p>

Why do shelf-incising submarine canyons form? - Insights from global topographic analyses and regression trees

2020 ◽  
Author(s):  
Anne Bernhardt ◽  
Wolfgang Schwanghart
Keyword(s):  
Continental Slope ◽  
Regression Trees ◽  
Signal Propagation ◽  
Sediment Supply ◽  
Sediment Flux ◽  
Slope Gradient ◽  
Submarine Canyons ◽  
Data Set ◽  
Sediment Routing ◽  
River Mouths

<p>The efficiency of environmental signal propagation from terrestrial sources to marine sinks highly depends on the connectivity of the sediment-routing system. Submarine canyons that couple river outlets with marine depocenters are particularly crucial links in the routing network as they convey terrestrial sediment, associated pollutants and organic carbon to the deep ocean. However, why and where submarine canyons incise into shelves is still poorly understood. Several factors were proposed, including narrow shelves along active continental margins, onshore sediment flux, more proximal sediment supply during sea-level lowstands, mass wasting along high-gradient continental slopes, and the occurrence of durable bedrock in adjacent catchments. In this study, we test whether we can predict shelf incision of submarine canyons from onshore and offshore parameters.</p> <p>We used maps of global elevation and bathymetry and analyzed them together with a global compilation of 5900 submarine canyon heads. The analysis relies on bagged regression trees that predict the distance of each canyon head from the shelf edge as a function of numerous candidate predictor variables. These variables describe spatial relations of river mouths and canyons, shelf geometry, continental slope gradient, as well as numerous terrestrial catchment properties. Moreover, we added 120 m to the elevation of the present-day topography to simulate a coastal landscape during the Last Glacial Maximum (LGM) and recalculated the topographic terrestrial parameters and the shelf width.</p> <p>The trained model explains 66% (R<sup>2</sup>) of the variance within the data set with a root mean square error (RMSE) of 31 km and a mean absolute error (MAE, less sensitive to outliers) of 17 km. The highest predictor importance is consistently reported for the weighted distance from canyon heads to the adjacent river mouths during the LGM and the present-day catchment gradient. We find no significant influence of shelf width, continental slope gradient and sediment load, and the moderate fit of the model indicates that we are still missing one or more important controls on the spatial location of canyon heads. Our predictions may be refined by including a more detailed assessment of catchment lithologies, locations of submarine groundwater discharge, locations of tectonic faults, and longshore current directions. Notwithstanding, we conclude that our model identifies important controls on the spatial occurrence and shelf incision of submarine canyons and sorts out much debated but seemingly unimportant variables.  </p>

Tracking signal propagation through landscapes using a granular avalanching system

2021 ◽  
Author(s):  
Chloe Griffin ◽  
Jonathan Higham ◽  
Robert Duller ◽  
Kyle Straub
Keyword(s):  
Solid Phase ◽  
Power Spectra ◽  
Signal Propagation ◽  
Sediment Flux ◽  
Spherical Particles ◽  
Particle Interactions ◽  
Time Step ◽  
Environmental Signals ◽  
Physics Model ◽  
Pile Model

<p>Landscapes have the ability to transmit environmental signals or inhibit them. The mechanisms by which landscapes do this are largely unquantified, but is probably due to the ability of landscapes to transiently store and release sediment which acts as a medium for energy to propagate. Previous experiments using 1D avalanching rice piles suggest that stochastic collapses can overprint, or shred, periodic sedimentary signals (Jerolmack and Paola (2010), as measured using mass efflux from the experimental rice pile. Jerolmack and Paola (2010) defined a threshold for successful surface signal propagation: Tx, where signals with a period less than Tx are shredded, unless the magnitude of the signal is sufficiently large. We aim to utilise the rice pile to further investigate signal propagation across a landscape, and the thresholds for this, by quantifying inter-particle interactions and the mechanics of how signals propagate using a quasi-2D rice pile model, built using MFiX-DEM code. This open source, physics model utilises individual particles which compose the solid phase whilst treating the fluid as a continuum. The rice grains in the model are represented by spherical particles, where each individual particle, or cluster of particles, can be tracked through each time step using a coordinate axis system, allowing internal dynamics, such as avalanche sizes and sediment residence times, to be quantified. To certify the model replicates the self-organised nature of an experimental rice pile, sensitivity tests were performed by systematically changing two key parameters controlling grain interactions: the friction coefficient and the coefficient of restitution, alongside the sediment flux. To calibrate the results of the sensitivity analysis, mass efflux through time and the corresponding power spectra are compared to real experimental rice pile results and statistical rice pile models. It is hoped this work will provide fundamental insights into how a signal propagates through a landscapes, and how they are shredded in the process.   </p>

scholarly journals Tracking the <sup>26</sup>Al/<sup>10</sup>Be source-area signal in sediment-routing systems of arid central Australia

2018 ◽  
Author(s):  
Martin Struck ◽  
John D. Jansen ◽  
Toshiyuki Fujioka ◽  
Alexandru T. Codilean ◽  
David Fink ◽  
...  
Keyword(s):  
Source Area ◽  
Stream Sediments ◽  
Sediment Supply ◽  
Sediment Flux ◽  
Environmental Signals ◽  
Source Areas ◽  
Sediment Routing ◽  
Aeolian Dunes ◽  
Central Australia ◽  
Cosmogenic 10Be

Abstract. Sediment-routing systems continuously transfer information and mass from eroding source areas to depositional sinks. Understanding how these systems alter environmental signals is critical when it comes to inferring source-area properties from the sedimentary record. We measure cosmogenic 10Be and 26Al along three large sediment-routing systems (~ 100,000 km2) in central Australia with the aim of tracking downstream variations in 26Al/10Be inventories and to identify the factors responsible. By comparing 56 new cosmogenic 10Be and 26Al measurements in stream sediments with matching data (n = 55) from source areas, we show that 26Al/10Be inventories in hillslope bedrock and soils set the benchmark for relative downstream modifications. Lithology is the primary determinant of erosion-rate variations in source areas and despite sediment mixing over hundreds of kilometres downstream a distinct lithological signal is retained. Postorogenic ranges yield catchment erosion rates of ~ 6–11 m/m.y. and silcrete-dominant areas erode as slow as ~ 0.2 m/m.y. 26Al/10Be inventories in stream-sediments reveal overall downstream-increasing minimum cumulative burial terms up to ~ 1.1 m.y. but more generally ~ 400–800 k.y. The magnitude of the burial signal correlates with increasing sediment cover downstream and reflects assimilation from storages with long exposure histories, such as alluvial fans, desert pavements, alluvial plains, and aeolian dunes. We propose that the tendency for large alluvial rivers to mask their 26Al/10Be source-area signal differs according to geomorphic setting. Signal preservation is favoured by i) high sediment supply rates, ii) high mean runoff, and iii) a thick sedimentary basin pile. Conversely, signal masking prevails in landscapes of i) low sediment supply, ii) discontinuous sediment flux, and iii) juxtaposition of sediment storages with notably different exposure histories.

scholarly journals Times Associated With Source-to-Sink Propagation of Environmental Signals During Landscape Transience

2021 ◽  
Vol 9 ◽  
Author(s):  
Stefanie Tofelde ◽  
Anne Bernhardt ◽  
Laure Guerit ◽  
Brian W. Romans
Keyword(s):  
Grain Size ◽  
Response Times ◽  
Signal Propagation ◽  
Large River ◽  
River Systems ◽  
Environmental Signals ◽  
Sediment Routing ◽  
Short Period ◽  
Different Types ◽  
Marine Realm

Sediment archives in the terrestrial and marine realm are regularly analyzed to infer changes in climate, tectonic, or anthropogenic boundary conditions of the past. However, contradictory observations have been made regarding whether short period events are faithfully preserved in stratigraphic archives; for instance, in marine sediments offshore large river systems. On the one hand, short period events are hypothesized to be non-detectable in the signature of terrestrially derived sediments due to buffering during sediment transport along large river systems. On the other hand, several studies have detected signals of short period events in marine records offshore large river systems. We propose that this apparent discrepancy is related to the lack of a differentiation between different types of signals and the lack of distinction between river response times and signal propagation times. In this review, we (1) expand the definition of the term ‘signal’ and group signals in sub-categories related to hydraulic grain size characteristics, (2) clarify the different types of ‘times’ and suggest a precise and consistent terminology for future use, and (3) compile and discuss factors influencing the times of signal transfer along sediment routing systems and how those times vary with hydraulic grain size characteristics. Unraveling different types of signals and distinctive time periods related to signal propagation addresses the discrepancies mentioned above and allows a more comprehensive exploration of event preservation in stratigraphy – a prerequisite for reliable environmental reconstructions from terrestrially derived sedimentary records.

scholarly journals Conceptual model of sedimentgraph from flood events in a small agricultural watershed

2008 ◽  
Vol 39 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Kazimierz Banasik ◽  
J. Mitchell
Keyword(s):  
Conceptual Model ◽  
Suspended Sediment ◽  
Sediment Concentration ◽  
Agricultural Watershed ◽  
Sediment Flux ◽  
Flood Events ◽  
Rainfall Events ◽  
Sediment Routing ◽  
Suspended Sediment Flux ◽  
Lag Times

Conceptual model of sedimentgraph from flood events in a small agricultural watershed A procedure for predicting the sediment graph (i.e. the suspended sediment flux), from a small river catchment by heavy rainfall, has been developed using the concept of an instantaneous unit hydrograph (IUH) and dimensionless sediment concentration distribution (DSCD). A formula for instantaneous unit sedimentgraph (IUSG) is presented, and a procedure for estimating the sediment routing coefficient, which is a key parameter of the IUSG, based on measured data of rainfall-runoff-suspended sediment is applied. Field data from a small, field sized agricultural basin, lacated in center of Illinois has been used for analizing lag times for runoff (LAG) and sediment yield (LAGs). Assumptions about sediment generated during rainfall events are discussed.

Field-Scale Analysis of a Stormwater Infiltration Trench’s Failure Mechanisms

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Tobias Mueller ◽  
John Komlos ◽  
Conor Lewellyn ◽  
Andrea Welker ◽  
Robert G. Traver ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Scale Analysis ◽  
Field Scale ◽  
Stormwater Infiltration

New Workflow of Sediment Mass Balancing, from Local Datasets, for Predicting Basin Scale Trends

2021 ◽  
Author(s):  
Nikolaos A. Michael ◽  
Rainer Zuhlke
Keyword(s):  
Grain Size ◽  
Integrated Approach ◽  
Sediment Flux ◽  
New Approach ◽  
Sediment Volume ◽  
Denudation Rates ◽  
Sediment Routing ◽  
Local Areas ◽  
Catchment Size ◽  
Areas Of Interest

Abstract Objectives/Scope Sediment volumetric budget estimates are very important input parameters for process-based depositional modelling (forward stratigraphic modelling). This paper presents a new integrated approach for analyze sediment volumetric budgets in sedimentary basins that is based on the reconstruction of regional grain size trends. In subsurface studies of sediment routing systems, noticeable uncertainties in estimated total sediment volumes occur when available datasets are limited to local areas that do not cover the entire sediment routing system. These uncertainties also affect models of catchment areas, structural uplift, and denudation rates as well as net:gross predictions. Methods, Procedures, Process The new integrated approach focuses on reconstructing sediment budgets for entire sediment fairways from limited local datasets. It uses a combination of sediment mass balancing and local grain size distributions to predict basin-wide grain size distributions. The comparison of local grain size to fairway-scale grain size trends is key in correcting sediment volumetrics for significantly reduced uncertainties in catchment reconstruction and net:gross ratios predictions at the scale of sediment fairways, sub-basins, prospects and exploration/production fields. Results, Observations, Conclusions The new approach has been applied successfully to two subsurface continental to marine delta systems. They cover periods of approximately 7 My in total and include four limited local areas of interest (AOI). These local AOIs measure 200×200 km, while the entire sub-basin measures 500×800 km. The new approach indicates that only up to 40% of the total sediment volume of each fairway could be captured by previous methodologies with limited local areas of interest. A maximum of 70% of the entire sink sediment volume could be incorporated in local areas of interest. The new approach presented in this paper significantly lowers the uncertainties in sediment volume estimates, depositional rates and lithology distribution input parameters in forward stratigraphic modelling. For the two case studies, previous sediment flux models indicated rates of 10,000 km/Myr. The new integrated approach indicates that sediment flux actually reached 30,000 km/Myr with major implications for sediment distribution, net:gross prediction and catchment size and denudation rates estimates. Novel/Additive Information The new integrated approach reduces uncertainties in catchment size and tectonic exhumation rate estimates for clastic depositional systems. It provides lower uncertainty parameters (sediment volume, source locations, sediment fractions, diffusion coefficients) for forward stratigraphic modelling, e.g., for reservoir quality prediction in hydrocarbon exploration. In fundamental research, provenance analyses can be better constrained by improved catchment size prediction and sediment grain size distribution models for sink areas

Provenance of detrital sediments in Santa Barbara Basin, California, USA: Changes in source contributions between the Last Glacial Maximum and Holocene

2019 ◽  
Vol 132 (1-2) ◽  
pp. 65-84 ◽  
Author(s):  
Tiffany J. Napier ◽  
Ingrid L. Hendy ◽  
M. Florencia Fahnestock ◽  
Julia G. Bryce
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Sediment Flux ◽  
Santa Barbara ◽  
Santa Barbara Basin ◽  
Last Glacial ◽  
Sediment Routing ◽  
Source Contributions ◽  
Terrestrial Sediments ◽  
Isotope Mixing Models

AbstractDetrital terrestrial sediments preserved in near-shore marine basins bear distinctive geochemical identifiers that can be used to identify the on-shore sediment sources and sediment routing through time. Santa Barbara Basin (SBB), offshore of southern California, USA, contains a well-known, continuous, high-resolution Holocene flood record that can provide insights into the frequency and changes in on-shore sources across time for such events. Here SBB-adjacent stream bed sediments are characterized using mineralogical, elemental, and radiogenic strontium and neodymium isotopic compositions. Modern and Holocene SBB flood deposits and Last Glacial Maximum (LGM) sediments were similarly analyzed. The Southern Slopes of the Santa Ynez Mountains and Topatopa Mountains account for ∼85% of SBB Holocene flood deposit sediments, as calculated from Sr-Nd isotope mixing models. During the LGM sea level low stand, the Southern Slopes contribution increased (to ≥90%), while relative sediment contribution from Santa Clara River diminished. This loss was likely compensated, however, by increased sediment flux from the Southern Slopes and the Channel Islands.

scholarly journals Annually Laminated Lake Sediments—Recent Progress

Quaternary ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 5 ◽  
Author(s):  
Wojciech Tylmann ◽  
Bernd Zolitschka
Keyword(s):  
Lake Sediments ◽  
Recent Progress ◽  
Sediment Traps ◽  
Sediment Flux ◽  
Research Directions ◽  
Environmental Signals ◽  
Sediment Research ◽  
Varved Sediment ◽  
Spatiotemporal Analyses ◽  
Annually Laminated Lake Sediments

The collection of papers entitled “Annually Laminated Lake Sediments” illustrates the recent progress made in varved sediment research and highlights the variety of methodological approaches and research directions used. The contributions cover the monitoring of modern sediment fluxes using sediment traps, geochronological and sedimentological analyses of varves, multi-proxy investigations, including geochemical and biological proxies, as well as spatiotemporal analyses based on multi-core studies supported by satellite images. The scientific issues discussed the influences of hydroclimatological phenomena on short-term changes in sediment flux, the relationships between biogeochemical processes in the water column and the formation of varves, the preservation of environmental signals in varves, and possibilities of synchronizing varved records with other high-resolution environmental archives.

Sign in / Sign up

Export Citation Format

Share Document