Figure - available from: Journal of Geophysical Research: Earth Surface
This content is subject to copyright. Terms and conditions apply.
Conceptual diagram of a sediment routing system (SRS) and the major impediments to stratigraphic storage of environmental signals. SRSs transport sediment from erosional sources to depositional sinks and are sensitive to environmental forcings (climate, tectonics, and sea level). Propagation of signals of these forcings across the Earth surface and into the stratigraphic record is influenced by three primary impediments shown in schematic form in subpanels. Each impediment can affect any section of a SRS, but for simplicity we highlight just one impediment per transport system segment. (a) The propagation of environmental signals is buffered via the interaction of channels with landscapes. For example, step changes in tectonic uplift experienced in catchments produce muted sediment flux signals with time lags at catchment outlets. These sediment flux signals become more muted with additional transport through fluvial SRSs. The amount of buffering can be predicted by comparing the duration or period of an environmental forcing with a system's equilibrium timescale (Teq). (b) The stochastic relocation of SRSs, for example, through depositional lobe avulsions in deepwater systems, can convert a continuous input sediment supply signal into a discrete and discontinuous record with time preserved in sedimentary beds separated by gaps or hiatuses of nondeposition. The duration of these hiatuses is limited by the system's compensation timescale (Tc). (c) Cut‐and‐fill processes in net depositional settings can shred environmental signals prior to stratigraphic storage by smearing input signals though space and time. When environmental forcings, for example, changing sea level, have magnitudes and periods less than autogenic timescales, they are prone to shredding. As such, stratigraphic scales, for example, deposition rates, parasequences or scours associated with the forcing, might be indistinguishable from autogenic stratigraphic scales.
Source publication
Plain Language Summary
Reconstructing the history of Earth prior to the age of scientific instrumentation relies heavily on interpretations of layers of sedimentary rocks, collectively called the stratigraphic record. The composition, architecture, chemistry, and fossils contained in these rocks provide signals of past climate, tectonics, and biolo...
Similar publications
ABSTRAKWilayah dataran aluvial hingga pantai daerah Demak, Kudus, Jepara, Pati dan sekitarnya ditutupi endapan sedimen Holosen yang terdiri atas kerikil, pasir, lempung, lanau, dan bongkah batuan gunungapi. Penelitian dilakukan dengan analisis sedimentologi dan stratigrafi terhadap 37 pemboran berskala 1 : 100 dengan ketebalan sedimen antara 0,8 -...
Citations
... External environmental perturbations (e.g., base level, water and sediment supply) can change the pace and magnitude of river processes and cause architectural changes in fluvial stratigraphy. Reading preserved fluvial strata for past changes is, however, complicated by noise generated by autogenic dynamics (Ganti et al., 2014;Hajek & Straub, 2017;Jerolmack & Paola, 2010;Romans et al., 2016), which can buffer, distort or even obliterate the record of past environmental changes (Foreman & Straub, 2017;Straub et al., 2020). Previous work quantified the scales of environmental changes that can be influenced by noise in sediment transport systems (Foreman & Straub, 2017;Ganti et al., 2014;Jerolmack & Paola, 2010). ...
Plain Language Summary
Bedforms are wavy features found regularly on the beds of rivers. Bedform deposits are the building blocks of the rock record on Earth and Mars. Bedforms and their deposits respond to floods; however, it is unclear if all floods are similarly represented in bedforms and their deposits. To address this, we identified the timescales over which bed elevation and sediment discharge are variable in a steady‐state experiment of bedform evolution using high‐resolution data. We investigated the time series of bed elevation to document the existence of bedform groups, which represent a collection of bedforms that have deep scours at their upstream and downstream end. We find that the turnover timescales (time required to move an entire land feature) of bedforms and bedform groups are the key controls on noise in bedform evolution. Results suggest that the signal of floods with duration less than bedform turnover timescale will not be found in bedform data and their deposits. However, floods with duration greater than the bedform‐group turnover timescale are likely to be expressed in bedform data and their deposits. These results provide a new theory for how floods are represented in river deposits.
... The internal dynamics within sediment-transport systems (STSs) are characterized by local episodes of sediment storage and release that occur naturally, known as autogenic processes, which are ubiquitous across all landscapes and generate stochastic fluctuations in sediment transport in the absence of external (allogenic) forcing Jerolmack, 2011;Jerolmack & Paola, 2010;Kim & Jerolmack, 2008;Paola, 2016;Pelletier et al., 2015;Romans et al., 2016;Straub et al., 2020). Stochastic sediment transport resulting from autogenic processes generates noise within a STS, and the resultant stratigraphy, and limits the predictability of STS dynamics (Ganti et al., 2014;Jerolmack, 2011;Jerolmack & Paola, 2010;Paola, 2016;Romans et al., 2016;Van De Wiel et al., 2011). ...
... However, a time series of stratigraphic information is inherently incomplete owing to the presence of hiatuses over a variety of spatiotemporal scales from laminae to basin-scale unconformities, which reduce the preservation of autogenic processes within vertical sections (Ager, 1973;Davies et al., 2019;Foreman & Straub, 2017;Jerolmack & Sadler, 2007;Kemp, 2012;Sadler, 1981;Schumer & Jerolmack, 2009;Sommerfield, 2006). Within all geomorphic environments, variations exist in the duration of depositional, stasis (non-deposition) and erosional events driven by autogenic reorganization, which generates hiatal surfaces with a range of frequencies and durations Kim & Jerolmack, 2008;Sadler, 1981;Sommerfield, 2006;Straub & Foreman, 2018;Straub et al., 2020;Strauss & Sadler, 1989;Tipper, 2015;. As a result, part of the original autogenic signal is removed and imposed sediment flux signals can be distorted (e.g., Burgess et al., 2019;Foreman & Straub, 2017;, making it challenging to accurately reconstruct sediment-transport processes and detect environmental signals from landscapes and strata (Kemp, 2012(Kemp, , 2016Kemp & Sexton, 2014;Miall, 2015;Paola et al., 2018;Straub et al., 2020;Tofelde et al., 2021). ...
... Within all geomorphic environments, variations exist in the duration of depositional, stasis (non-deposition) and erosional events driven by autogenic reorganization, which generates hiatal surfaces with a range of frequencies and durations Kim & Jerolmack, 2008;Sadler, 1981;Sommerfield, 2006;Straub & Foreman, 2018;Straub et al., 2020;Strauss & Sadler, 1989;Tipper, 2015;. As a result, part of the original autogenic signal is removed and imposed sediment flux signals can be distorted (e.g., Burgess et al., 2019;Foreman & Straub, 2017;, making it challenging to accurately reconstruct sediment-transport processes and detect environmental signals from landscapes and strata (Kemp, 2012(Kemp, , 2016Kemp & Sexton, 2014;Miall, 2015;Paola et al., 2018;Straub et al., 2020;Tofelde et al., 2021). Furthermore, limits on our ability to date strata mean sediment age is often assigned by linear interpolation between dated horizons (Abels et al., 2010;Ramos-Vázquez et al., 2017), providing additional challenges to the incompleteness problem by distorting the apparent representation of time in strata relative to true time (Barefoot et al., 2023;. ...
Spectral analysis is a central tool regularly used by the scientific community to identify the presence of periodic processes within a time series of information, as spectral peaks at an imposed periodicity can be differentiated from internal (autogenic) variance. In scientific disciplines, such as seismology, the time series of information is of high temporal resolution. Hence, although temporal gaps are present, they do not impact the overall noise structure, meaning that the full spectrum of autogenic variance can be reconstructed. However, power spectra generated from stratigraphic information are affected by temporal incompleteness due to varying episodes of erosion and geomorphic stasis, which generate gaps over a range of scales. This removes information related to the natural and autogenic variability present within sediment‐transport systems, which makes it challenging to accurately reconstruct the structure and strength of paleo‐surface processes, which defines the detectability of past environmental signals. We explore how incompleteness impacts the temporal structure of autogenic noise within power spectra, and how this influences the detectability of spectral spikes related to environmental signals. We utilize a sediment flux time series from a physical rice pile and progressively degrade these data to mimic varying degrees of stratigraphic incompleteness. We find that incompleteness strongly influences the timescales and spectral structure of autogenic noise evident, and can render signals over all periodicities undetectable within a highly incomplete time series. This offers the ability to confidently justify the interpretation of subtle environmental signals from field measurements and understand the records that may best preserve paleoenvironmental variability.
... One of the challenges for geologists trying to improve the interpretation of the stratigraphic records is how to embrace hypothesis testing and the quantification of uncertainty in our interpretations of stratum (Straub et al., 2020) because of these factors, such as the sediment supply from the eroding source region, the grain size distribution of that sediment supply, and the area available or accommodation for sediment accumulation in the downstream regions, can make the interpretation of a climatic or tectonic signal complex, particularly as these processes are nonlinear (Armitage et al., 2011). Variations of stratal patterns are repositories for climate and lake level fluctuation signals, as they are sensitive to tectonic activity and dramatic climate change (Molnar, 2001;Zhang et al., 2001;Lu et al., 2022;Vallati et al., 2023). ...
The formation of vertical sedimentary succession of delta in the arid and semi-arid basin-margin progradation dramatically depends on the variation of sediment flux and accommodation, but the discontiguous record of signals tends to exist enormous variable, which renders the bulk record of microfacies difficult to quantify from the vertical sedimentary succession. We analyzed the 18 vertical sedimentary successions collected from 18 field trenches of lake delta by cusp-catastrophe model, allowing detailed mapping of microfacies. The present detailed study indicates the suitability of cusp-catastrophe theory for explaining vertical sedimentary succession in the BWH (Bawanghe) delta. Three equilibrium states of processes responsible for the deposition of BWH delta's evolution were established: sandy-dominated upper leaves primarily exhibit delta plain; sandy/muddy-dominated lower leaves present delta plain and pro-delta; and sandy-dominated middle leaves which commonly developed delta front. The result of analysis shows that the reliability of cusp-catastrophe model to identity mutation of vertical sedimentary succession exceeds 50 %, and to identity microfacies transitions with a precipitation periodicity exceeds 70 %. These cognitions support the previous view that changing precipitation results in an abrupt change in margin progradation. Simultaneously, the study gives new insights into the microfacies quantification of lake delta and reveals the influence of crest value changes of precipitation on vertical sedimentary succession can be understood from the dependence of microfacies distribution on the change of sediment flux and accommodation.
... While fewer strata appear to have been reworked in such settings, the deposition of new sediment occurred in erratic intervals, meaning that sediment was less mobile and a greater proportion of the elapsed time was spent in sedimentary stasis. Stasis is a sedimentation state during which neither deposition nor erosion occurs, leading to no change in the elevation of the lithic surface at a site (Tipper, 2015), and is increasingly recognised as an important factor in determining the fabric and time-completeness of the sedimentary-stratigraphic record (e.g., Tipper, 2015;Straub et al., 2020;Davies and Shillito, 2021). The palaeoecological role of sedimentary stasis has less frequently been remarked on but is known to be of importance in biogeomorphology and ecology. ...
The evolution of trees and forests through the Devonian Period fundamentally changed Earth's land biosphere, as well as impacting physical environments and geomorphology by stabilizing sediment and interacting with flowing air and water. From the mid Givetian Age onwards, lignophyte flora are known to have been key parts of the machinery in the ‘Devonian Landscape Factory’, but the impact of earlier forests, dominated by less woody cladoxylopsids, are not as well understood. In this paper we report evidence for a previously unrecognized cladoxylopsid forest landscape, archived within the Eifelian Hangman Sandstone Formation of Somerset and Devon, SW England. This unit has previously been considered palaeobotanically depauperate but is here shown to contain the earliest fossil evidence for such trees in the British record, as well as the oldest known evidence globally for the relative position of standing trees: in common parlance a ‘fossil forest’. In addition to abundant fossil material attributable to the cladoxylopsid tree Calamophyton , and other early Middle Devonian flora, the sedimentary context of the plant remains sheds light on the biogeomorphic impacts of these earliest forests. The trees colonized a sizeable distributive fluvial system (DFS) that was prone to seasonal disturbance events. The nature of the sedimentary system has created a bias to those facies where biogeomorphic signatures are most frequently recorded (from the distal parts of the system), but across the DFS there is evidence of plant-sediment interactions in the form of vegetation-induced sedimentary structures, rooting features, and accumulations of plant debris. Plant remains are also found in nearshore facies adjacent to the DFS, attesting to the development of a novel non-marine/marine teleconnection from the production and export of new biological sedimentary particles. The Hangman Sandstone Formation is illustrative of the revolutionary power of cladoxylopsid trees as biogeomorphic agents, forming densely spaced forests and shedding exceptionally abundant plant debris, whilst also impacting local landforms and sediment accumulations and profoundly changing landform resilience against flood disturbance events. These findings provide evidence that the Eifelian Stage (393.3-387.7 Ma) marks the onset of tree-driven changes to physical environments that would forever change Earth's non-marine landscapes and biosphere.
Supplementary material: https://doi.org/10.6084/m9.figshare.c.7084873
... The importance of internal dynamics as a driver of stratigraphic changes in the absence of dynamic external forcing has recently received considerable attention (for example, compensational stacking, Mutti & Sonnino, 1981;Mohrig et al., 2000; fluvial terraces generated by auto-incision, Muto & Steel, 2004; auto-reorganization of fluvial systems in hanging-wall basins, Kim & Paola, 2007). The findings in this work expand the current understanding of internal feedbacks in sedimentrouting systems and their resultant stratigraphic record, which in turn can provide important insight for discerning stratigraphic products of autogenic processes from the stratigraphic signals of climatic, tectonic and sea-level changes (Hajek et al., 2010;Burgess et al., 2019;Toby et al., 2019;Straub et al., 2020). ...
Nearshore incised valleys are important conduits for the transport of sediment, nutrients, pollutants and organic carbon from the continents to the sea. Therefore , it is essential to understand the autogenic evolution of deltas confined within incised valleys and how such evolution is affected by relative sea-level rise. To date, limited research has focused on how deltas constrained by incised valleys or other forms of antecedent topography respond to rising sea level. An existing theory of autostratigraphy envisages scenarios in which two-dimensional or unconfined three-dimensional fan deltas can experience three evolutionary stages under constant rates of relative sea-level rise and sediment supply: progradation, autoretreat and post-autobreak transgression. In this work, an integrated study of geometric numerical models and physical experiments is undertaken to investigate autostratigraphic delta evolution for a variety of incised-valley geometries, under conditions of constant rates of relative sea-level rise and sediment supply. Results indicate that interplays of antecedent topography (valley geometries) and sediment mass balance expressed in resultant deltaic geometries can result in autogenic changes in shoreline dynamics and river avulsion frequency on deltas. The following primary findings arise. (i) Compared to valleys with rectangular and trapezoidal cross-sectional profiles, valleys with triangular cross-sections tend to contain deltas that experience faster rates of progradation, autoretreat and post-autobreak transgression under rising sea level, and exhibit a more prominent convex-seaward shoreline trajectory. (ii) The shoreline trajectory is also related to delta topset geometry, becoming more convex-seaward under decreasing topset slopes. (iii) River avul-sion frequency on deltas with rising sea level varies markedly across valleys with different geometries, even under the same rate of relative sea-level rise; this is attributed to the difference in temporal evolution of shoreline migration for different valley geometries and the resultant difference in the delta topset aggradation. This study highlights complexities in responses of sedimentary systems under the confinement of different topographic configurations that have hitherto largely been overlooked in sequence-stratigraphic models. The findings provide insight into future shoreline behaviour and river avulsion hazard on confined deltas, and for decoding the stratigraphic record.
... Strata are often analysed to identify what, if any, signal they contain that records climate change, sea-level variations, or tectonic events (e.g. Blum et al., 2018;Somme et al., 2019;Straub et al., 2019;Tofelde et al., 2021;Sharman et al., 2023). Such analysis is an important element in reconstructing Earth history, but preservation and subsequent identification of external signals in strata is complicated. ...
... However, the relative values of periodicity, so the difference between shorter-period dominant allogenic signals and longer-period dominant autogenic signals, may well be significant, reflecting the rates at which depositional topography develops, influences subsequent flow deposition and avulsion, and creates organised stacking patterns, as documented in other modelling and outcrop studies (e.g. Hawie et al., 2015;Li et al., 2020;Hajek & Straub, 2019). In these models that autogenic stacking is typically expressed at longer periods of 50-100 flows, so 50-100ky. ...
... As ever, it is important to consider the limitations of any numerical model being used to make interpretations and draw conclusions. For example, Straub et al. (2019) state that "many numerical formulations do not generate the rich structure of strata that is required to explore limits of environmental signal recovery because they do not account for the stochastic variability of processes that contribute to the construction of strata". The implication seems to be that only stochastic processes can generate the necessary variability to create realistic strata, but the strata produced by simple, deterministic Lobyte3D models suggest otherwise. ...
... Watersheds, with internally heterogeneous physiography, contain sediment that experience a wide extent of weathering conditions, rates of OC turnover, and residence times. The transit of sediment across landscapes in rivers involves the erosion, suspension, and re-deposition of sediment that may buffer in situ biogeochemical signals (Straub et al., 2020). River suspended sediment thus encodes variable histories of watershed evolution, reducing the likelihood that their chemistry should directly follow one idealized soil formation pathway (Fig. 3B). ...
Silicate weathering and organic carbon (OC) burial in soil regulate atmospheric CO2, but their influence on each other remains unclear. Generally, OC oxidation can generate acids that drive silicate weathering, yet clay minerals that form during weathering can protect OC and limit oxidation. This poses a conundrum where clay formation and OC preservation either compete or cooperate. Debate remains about their relative contributions because quantitative tools to simultaneously probe these processes are lacking while those that exist are often not measured in concert. Here we demonstrate that Li isotope ratios of sediment, commonly used to trace clay formation, can help constrain OC cycling. Measurements of river suspended sediment from two watersheds of varying physiography and analysis of published data from Hawaii soil profiles show negative correlations between solid-phase
values and OC content, indicating the association of clay mineral formation with OC accumulation. Yet, the localities differ in their ranges of
values and OC contents, which we interpret with a model of soil formation. We find that temporal trends of Li isotopes and OC are most sensitive to mineral dissolution/clay formation rates, where higher rates yield greater OC stocks and lower
values. Whereas OC-enhanced dissolution primarily dictates turnover times of OC and silicate minerals, clay protection distinctly modifies soil formation pathways and is likely required to explain the range of observations. These findings underscore clay mineral formation, driven primarily by bedrock chemistry and secondarily by climate, as a principal modulator of weathering fluxes and OC accumulation in soil.
... This may reflect spatio-temporal consistency of grainsize fractions generated in the source areas and/or buffering and mixing of sediment supply in source-area catchments (e.g. Castelltort and Van Den Driessche, 2003;Jerolmack and Paola, 2010;Straub et al., 2020). The small gravel grain-size fractions (Fig. 11B) and net-depositional fluxes (Fig. 16) imply that gravel may have been retained in source-area catchments. ...
We reconstruct upsystem-to-downsystem grain-size variations in the sediment routing systems of the data-rich Middle Jurassic Brent Group of the northern North Sea, using published stratigraphic, thickness, palaeogeographic, provenance and age constraints combined with representative core and wireline-log data. Facies associations provide a textural proxy for gravel, sand and mud grain-size fractions, and their distributions define spatio-temporal variations in grain size within four previously documented genetic sequences (J22, J24, J26, J32). Sediment was sourced from the west (Shetland Platform), east (Norwegian Landmass) and south (Mid-North Sea High). The corresponding sediment routing systems were geographically distinct in the oldest (J22) and youngest (J32) genetic sequences, but combined to feed a large wave-dominated delta (‘Brent Delta’) in genetic sequences J24 and J26.Few of the Brent Group sediment routing systems exhibit the downsystem-fining grain-size trend predicted by sediment mass balance theory. Deviations from this reference trend reflect: (1) sparse sampling of channelised fluvial and fluvio-tidal sandbodies in upsystem locations; (2) preferential trapping of sand in underfilled antecedent and syn-depositional, half-graben depocentres in genetic sequences J22 and J32; and (3) nearshore retention of sand by shoaling waves in wave-dominated shoreface and barrier-strandplain systems. This third type of deviation reveals that spatial facies partitioning due to shallow-marine process regime distorts the simple downsystem-fining reference trend, and supports the interpretation that large volumes of predominantly muddy sediment were bypassed beyond the ‘Brent Delta’ into neighbouring basins. In summary, our analysis demonstrates a practical tool to interpret sediment supply and sediment dispersal in the stratigraphic record.
... Sediment transport systems (STSs) are sensitive to external environmental perturbations; these can be natural (e.g., related to climatic or tectonic processes) or anthropogenic in origin (1)(2)(3)(4)(5). STSs respond and adjust to these perturbations in a number of ways and over a range of temporal and physical scales (2,6). ...
... STSs respond and adjust to these perturbations in a number of ways and over a range of temporal and physical scales (2,6). A fundamental response of a STS to these perturbations is a variation in the generation of sediment supplied to the STS and transmitted down system as an environmental signal (4,7). These environmental sediment flux signals can generate geomorphic and stratigraphic signatures that allow for the reconstruction of past environmental perturbations (4,(7)(8)(9)(10)(11) and provide insight into the response of landscapes to future environmental change (12,13). ...
... A fundamental response of a STS to these perturbations is a variation in the generation of sediment supplied to the STS and transmitted down system as an environmental signal (4,7). These environmental sediment flux signals can generate geomorphic and stratigraphic signatures that allow for the reconstruction of past environmental perturbations (4,(7)(8)(9)(10)(11) and provide insight into the response of landscapes to future environmental change (12,13). ...
Autogenic processes contribute noise to sediment transport systems that can degrade or mask externally derived environmental signals and hinder our ability to reconstruct past environmental signals from landscapes and strata. To explore this further, we measure efflux from a physical rice pile to ascertain the temporal structure of autogenic noise, and how this influences the degradation and detection of environmental signals. Our results reveal a tripartite temporal spectral structure segmented at two key autogenic time scales. The shorter autogen-ic time scale set limits on environmental signal degradation, while the longer autogenic time scale sets limits on environmental signal detection. This work establishes a framework that can be used to explore how autogenic processes interact with external environmental signals in field-scale systems to influence their detectability. We anticipate that the temporal structure and associated time scales identified will arise from autogenic processes in numerous sediment transport systems.
... Morphodynamic filtering of downstream sediment transport signals can occur to different degrees, including (a) dampening when the signal amplitude is scaled down but the amplitude-frequency dependence remains; (b) delaying which may or may not accompany dampening but where there is a shift in phase; and (c) shredding where the amplitude-frequency dependence is partially or completely destroyed (Straub et al., 2020). Understanding the extent to which there is filtering and the distance over which it occurs is important for several disciplines. ...
Plain Language Summary
Alpine glaciers have been retreating at increasing rates since the early 20th century due to the current climate warming. As a consequence, new, powerful and rapidly changing rivers have developed in the newly emerged terrain in front of shrinking glaciers (i.e., proglacial forefields). These environments are known to be among the most rapidly changing landscapes on Earth. In this study we present the first combined high frequency quantitative data on sediment export from an Alpine glacier for two melt seasons with very different climatic conditions. Results show that the low potential transport distances of particles traveling on the river bed together with the continuously changing shape of these streams, rapidly modify the glacier‐dictated export signal (i.e., subglacial sediment evacuation rates in time). For sediment transported in suspension in the river, that loss of information is less evident. These findings are important for the understanding of how much, when, and which kind of sediment are delivered to the populated places downstream in the valleys, in order to mitigate natural hazards, but also for sediment management in hydropower plants and ecological succession in the context of rapid glacier retreat. The results are also key to improving estimation of glacial erosion rates.
