Project

Marie Skłodowska-Curie Innovative Training Network on Signal Propagation in Source to Sink for the Future of Earth Resources and Energy (S2S-Future)

Goal: S2S-Future is a Marie Sklodowska-Curie Innovative Training Network (MSCA ITN) funded by the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No 860383).
The objective of the project is to understand, quantify and model the sediment routing system from the sediment production (source) to the sediment deposition (sink).

Date: 1 April 2020

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Project log

Ariel H. Prado
added a research item
Climate changes have been considered an essential factor controlling the shaping of the recent alluvial landscapes in central Amazonia, with implications for explaining the biogeographic patterns in the region. This landscape is characterized by wide floodplains and various terrace levels at different elevations. A set of older terraces with ages between 50 and >200 ka occupy the higher portions of central Amazonia, whereas multiple terraces next to floodplains occur at lower elevations and display ages of a few thousand years. These lower terraces, referred to as middle–lower terraces, reveal what can be perceived as a stochastic pattern both in space and time. Despite the widespread occurrence of these geomorphic features, no process-oriented analysis has been conducted to explain their formation. Here, we develop a landscape evolution model referred to as SPASE (Sedimentary Processes and Alluvial Systems Evolution) to explicitly account for fluvial erosion and deposition in combination with lateral channel migration to explore the controls on terrace development. The model results show that the higher terraces were deposited under the condition of a higher base level for the basins upstream of the confluence between the Solimões and Negro rivers. The subsequent decrease in the base level initiated a phase of gradual incision, thereby resulting in the current fluvial configuration. The model also predicts that high-frequency climate changes resulted in the construction of middle–lower terraces at various elevations which, however, are all situated at lower elevation than the higher terrace levels. Our model shows that dry-to-wet shifts in climate, in relation to the modern situation, yield a landscape architecture where middle–lower terrace levels are better preserved than wet-to-dry changes in climate, again if the current situation is considered as reference. Finally, our results show that fast and widespread landscape changes possibly occurred in response to high-frequency climate changes in central Amazonia, at least since the Late Pleistocene, with great implications for the distribution and connectivity of different biotic environments in the region. Because of this short timescale of response to external perturbations, we suggest that the streams in central Amazonia possibly also respond in rapid and sensitive ways to human perturbations.
Benjamin Bellwald
added a research item
Trough mouth fans comprise the largest sediment deposits along glaciated margins, and record Pleistocene climate changes on a multi-decadal time scale. Sedimentation related to climate warming in polar regions and new challenges associated with the energy transition highlight the urge for better knowledge of these depocenters. Here, we present sedimentation models for the two largest of these depocenters-the Bear Island Fan on the western Barents Sea margin and the North Sea Fan on the northern North Sea margin-which are analogues for large glacial fans along the Antarctic and Greenland margins. We use extensive high-quality 3D reflection seismic cubes (37,200 km 2) as well as conventional 2D reflection seismic lines, and combine these datasets with lithological and geophysical borehole logs. The stratigraphy of trough mouth fans is dominated by contourites, glacigenic debris flows, meltwater turbidites, and megaslides, which together result in a thickness exceeding 2 km. Neogene to early Quaternary-age contourites are characterized by continuous and high-amplitude reflections in the seismic data. The contourites of the late Quaternary, in contrast, have a more transparent seismic facies, and onlap the escarpments shaped by the megaslides. The lithology of the contourites varies from fine clays to coarse sands. Meltwater turbidites are identified as high-amplitude reflections characterized by 4-100 m deep channels and sourced from multiple regions along the paleo-shelf break. The well-connected turbidite channels are 90-2100 m wide, and can be traced for distances of >100 km. These channels are both deeper and wider in the North Sea Fan compared to the Bear Island Fan. The lithology of these deposits has yet to be cored. Glacigenic debris flows are transparent packages of sediments, with a lens-shaped expression in the seismic profiles and lobe-shaped geomorphology in planar view. The grain size of glacigenic debris flows is typically more mud-dominated than for contourites, but glacigenic debris flows do include sandy beds at selected intervals. Glacigenic debris flows are more dominant in the high-latitude Bear Island Fan compared to the mid-latitude North Sea Fan. Megaslides consist of high-amplitude, deformed sediment that is constrained by steep headwalls and sidewalls. The megaslides within these two trough mouth fans have mainly occurred since the Late Pleistocene and fail along contouritic basal layers.
Aurora Garcia
added a research item
Trough mouth fans are important depocenters for glacial sedimentation in high latitude margins, recording sedimentological processes and their relationship with paleoclimatic fluctuations on short timescales-from decades to millennia. The volume of sediments accumulated in these fans varies significantly depending on the phase of the glacial cycle, with higher values typically reached during early retreats. The input of large volumes during short time intervals can potentially trigger submarine landslides and overpressure build-up, making the understanding of processes and proportions related to sedimentation in glaciated margins crucial, especially during periods of global warming. In this study we use high-quality 3D seismic cubes (vertical resolution of 2 m and bin size of 6.25 x 18.75 m) to delimitate different types of deposits on an area over 14000 km 2 on the North Sea Trough Mouth Fan during a full glacial-interglacial cycle of the last glaciation (Weichselian). After mapping the corresponding top and base surfaces of each type of deposit their volumes were calculated using the mean thickness of the beds multiplied by their extent. The base of the studied package comprises a contourite body deposited on top of the Tampen Slide, whose failure is estimated to have happened around 130 ka ago. Next we have a thick (> 400 m) mixed package of debris flows and meltwater turbidites, with its rapid deposition happening during approximately 4 ka (~23 to 19 ka). The package is then completed with plume settling related to the full retreat of the ice stream. Although not completely interpreted due to limitations of the dataset extent and remobilization of a part of the fan by the Storegga Slide in the northern part, the last glacial cycle comprises a total of 7160 km 3 of sediments, with more than half of it (4850 km 3) originated from the downslope processes. The plumites and contourites comprise volumes of 1105 km 3 and 1205 km 3. This accounts to a significant variability of the magnitude of sediment volume coming into the sink per year, with the downslope deposits having over 100 times more sediment input and the plumites 5 times more when compared to the contourites. These results highlight the range of sediment volume that can be delivered in a glaciated margin depending on changes in processes and climatic fluctuations, which may also
Aurora Garcia
added a research item
Understanding the sedimentary processes and resulting deposits along glaciated margins, that can be recorded in trough mouth fans (TMF), is crucial to increase knowledge about ice sheet dynamics. Their behavior influences Earth’s climate system and sea level variations, from regional to global scale, during relatively rapid timescales (up to millennia). This study uses high-quality 3D seismic reflection data of the uppermost North Sea Trough Mouth Fan to document the seismic stratigraphy, sedimentary processes and glacio-marine landforms shaped during the last glacial highstand (23-19 ka). The stratigraphy of the fan is characterized by thick (~400m) prograding sequences. Facies analyses and seismic geomorphology show three main depositional processes (contour-currents, gravity-driven flows and setting of plumes), mappable as seven seismic sub-units in the studied interval. Contour currents are responsible for the deposition of the lowermost two sub-units (U1 and U2), characterized by continuous reflections with increasing amplitude contrasts near the Tampen Slide escarpment. U1 is dominated by positive amplitudes with mostly tabular geometry. U2, identified in the northern part, is dominated by negative amplitudes with lenticular geometry and is synchronous with the glaciation onset. These sub-units are followed by a succession of relatively homogeneous facies interrupted by continuous high-frequency horizons that subdivide the succession into four sub-units (U3-6). These sub-units are characterized by channels, presumably generated by meltwater-fed turbidity flows, varying in width, varying in depth from 10 to 60m and with suggesting high-energy episodes that creates channels deeper than 100m. They are pervasive throughout the sequences and across the fan and are commonly isolated with low sinuosity. The uppermost sequence (U7) is dominated by deposition of the suspended load and ice-raft debris, characterized by parallel and slightly undulated continuous inner reflections, thinning out downslope. Along the shelf, multiple cross-cutting of iceberg scours and pits are observed. The succession with channels evidence that meltwater can play a major role in TMF sedimentation. These new insights about the smaller-scale processes within seismic resolution demonstrate the variability of active processes during a fast sedimentation period of the Weichselian Glaciation at the North Sea Trough Mouth Fan.
Aurora Garcia
added a research item
Trough mouth fans are large depocentres forming the ultimate sinks in glacial source-to-sink systems. Their architecture, sedimentological aspects (origin and processes) and their role as paleoclimatic archives are essential components in improving our understanding of Pleistocene and ongoing climate changes. For many years, these depocentres were thought to be dominated by debris flows accumulated in front of ice streams located at the shelf break. However, recent studies have shown that meltwater plays a major role in bringing sediment to the most distal parts of these fans, especially in lower latitudes. The North Sea Trough Mouth Fan encompasses 110,000 km 2 with water depths of up to 3500 m. It has received sediments throughout the Quaternary, with increased sedimentation rates in the last 1.1 Ma when the Norwegian Channel Ice Stream was active. Recent insight of the fan shows that meltwater turbidites play a major role in sediment delivery to the continental slope and deep-sea basin. The results could entail distinct morphologies for mid-latitude and high-latitude fans. As a result of glacial erosion and the absence of clear imprints of ice sheets on the paleo-shelves, studying trough mouth fan deposits becomes paramount in understanding glacial-interglacial cycles. This project will assess the source-to-sink parameters of the last glaciation (Weichselian) at the North Sea Fan, elucidating the dominant marine and terrestrial processes that led to the studied sedimentary sequences. High-resolution 2D and 3D seismic data, core, volumetric and numerical modeling data will be assimilated to establish a source-to-sink model for the target interval. These results will contribute to the knowledge of how glaciations affect surface mass redistribution, directly affecting the landscape dynamics and sediment routing from Fennoscandia via the North Sea to the slopes and deep basin. Sediment production will be evaluated, assessing whether it increases during the glaciation or if observed higher sedimentation rates are a result of enhanced sediment transport. This project is a part of the Marie Sklodowska-Curie Innovative Training Networks "S2S-Future: Signal propagation in source to sink for the future of the Earth resources and energy" and will further advance how trough mouth flans are highly dynamic areas where sediment transport, dispersal, remobilization and deposition take place, and serve as excellent proxies to the dynamics of glacial pulses in the hinterland.
Benjamin Bellwald
added a research item
Proglacial braided river systems discharge large volumes of meltwater from ice sheets and transport coarse-grained sediments from the glaciated areas to the oceans. Here, we test the hypothesis if high-energy hydrological events can leave distinctive signatures in the sedimentary record of braided river systems. We characterize the morphology and infer a mode of formation of a 25 km long and 1–3 km wide Early Pleistocene incised valley recently imaged in 3-D seismic data in the Hoop area, SW Barents Sea. The fluvial system, named Bjørnelva River Valley, carved 20 m deep channels into Lower Cretaceous bedrock at a glacial paleo-surface and deposited 28 channel bars along a paleo-slope gradient of ~0.64 m km ⁻¹ . The landform morphologies and position relative to the paleo-surface support that Bjørnelva River Valley was formed in the proglacial domain of the Barents Sea Ice Sheet. Based on valley width and valley depth, we suggest that Bjørnelva River Valley represents a braided river system fed by violent outburst floods from a glacial lake, with estimated outburst discharges of ~160 000 m ³ s ⁻¹ . The morphological configuration of Bjørnelva River Valley can inform geohazard assessments in areas at risk of outburst flooding today and is an analogue for landscapes evolving in areas currently covered by the Greenland and Antarctic ice sheets.
Milica Pejovic
added a project goal
S2S-Future is a Marie Sklodowska-Curie Innovative Training Network (MSCA ITN) funded by the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No 860383).
The objective of the project is to understand, quantify and model the sediment routing system from the sediment production (source) to the sediment deposition (sink).