Submarine channel evolution, terrace development, and preservation of intra-channel thin-bedded turbidites: Mahin and Avon channels, offshore Nigeria

Hansen, Larissa; Janocko, Michal; Kane, Ian A.; Kneller, Benjamin Charles

doi:10.1016/j.margeo.2016.11.011

Cited by 81 publications

(76 citation statements)

References 66 publications

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“…This has a consequence for the likelihood of microplastic remobilization by subsequent turbidity currents, for sampling methodology (as most studies sample only the uppermost few centimeters of beds), as well as the availability of microplastics to ingestion by seafloor and/or burrowing fauna (Wright et al, 2013). In situations where a flow is constrained by topography (e.g., within a channel), the upper part of the overspilling flow will tend to concentrate particles that have a low settling velocity (e.g., Kane et al, 2007;Hansen et al, 2015Hansen et al, , 2017McArthur et al, 2017), making depositional areas such as levees more likely sites for microplastics accumulation. A summary of deep-marine gravity flow deposit types and likely microplastic distribution is presented in Figure 10.…”

Section: Gravity Flow Depositsmentioning

confidence: 99%

“…Submarine channels are long-term conduits for sediment transport and extend from the canyon into the deeper basin, and terminate in lobe deposits beyond the channel mouth (Normark, 1970;Pickering et al, 1989;Mutti and Normark, 1991;Normark et al, 1997;Peakall et al, 2000;Jobe et al, 2015;Hansen et al, 2017). Channels may be bound at their margins by erosional surfaces or levees, or both (e.g., Clark and Pickering, 1996;Li P. et al, 2016).…”

Section: Submarine Channelsmentioning

confidence: 99%

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Dispersion, Accumulation, and the Ultimate Fate of Microplastics in Deep-Marine Environments: A Review and Future Directions

2019

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Kane and Clare Microplastics in Deep-Marine Environments environments, their distribution and ultimate fate, and the implications that these have for benthic ecosystems. The dispersal of anthropogenic across the sedimentary systems that cover Earth's surface has important societal and economic implications. Sedimentologists have a key, but as-yet underplayed, role in addressing, and mitigating this globally significant issue.

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Section: Gravity Flow Depositsmentioning

confidence: 99%

Section: Submarine Channelsmentioning

confidence: 99%

Dispersion, Accumulation, and the Ultimate Fate of Microplastics in Deep-Marine Environments: A Review and Future Directions

2019

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“…Talling et al, 2015). Moreover, several studies have shown that quasi-linear submarine channel long profiles are common (e.g., Covault et al, 2011;Georgiopoulou and Cartwright, 2013;Hansen et al, 2016). For this reason, we prefer to evaluate submarine channel long profile and planform responses to a known deformation field and to deduce what this tells us about their time-integrated evolution and geometry rather than assuming a priori we know the steady-state concave form.…”

Section: Channel Response To Seabed Structuresmentioning

confidence: 99%

Quantifying the geomorphic response of modern submarine channels to actively growing folds and thrusts, deep-water Niger Delta

Jolly

Whittaker

Lonergan

2017

Geological Society of America Bulletin

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The interaction between submarine channels and active seabed deformation controls sediment delivery to the deep sea. Here, we combined seismic and geomorphic techniques to investigate quantitatively how the gravity-driven growth of thrust-related folds in the deep-water Niger Delta has influenced the morphology of four Pleistocene to Holocene submarine channels with present-day geomorphic expression. We extracted the bathymetric long profile of each of these modern seabed channel systems, and we evaluated the down-system evolution of channel widths, depths, and slopes as they have interacted with growing seabed structures. This information was used to derive estimates of bed shear stresses and velocities, to infer morphodynamic processes that have sculpted the channel systems through time, and to evaluate how these channels have responded to actively growing structures in the toe of the delta. The long profiles of these channels are relatively linear, with concavity from −0.08 to −0.34, and an average gradient of ∼1°. They are characterized by small knickpoints that are apparent near mapped structures and therefore implicitly reflect variations in substrate uplift rate. Channel incised depths increase significantly near the active structures, leading to entrenchment, but there is little change in the down-system distribution of channel width, in contrast to rivers crossing active faults, or buried submarine channel complexes. Reconstructed bed shear stresses near faults are estimated to lie in the range of 100−200 Pa, which would be associated with turbidite flow velocities of 2−4 m/s. A comparison of the magnitude and distribution of structural uplift since 1.7 Ma and the distribution of channel incision over this time shows that three of these channels have been able to keep pace with the time-integrated uplift since 1.7 Ma and have likely reached a local topographic steady state. Entrenchment of the submarine channels upstream of growing folds helps to drive this process, and we estimate that bed shear stresses of >100 Pa are sufficient to keep pace with structural strain rates of ∼4 × 10−3 m.y.−1

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“…(), Gamboa and Alves (), Qin et al. () and Hansen, Janocko, Kane, and Kneller (). Detailed morphological analyses (Figure ) of sediment conduits were only performed on the 3‐D seismic data, whereas the 2‐D seismic lines were used for regional correlations of horizons and units (Figures a and a,c).…”

Section: Data and Approachmentioning

confidence: 99%

Morphometric analysis of sediment conduits on a bathymetric high: Implications for palaeoenvironment and hydrocarbon prospectivity

et al. 2018

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Canyons and other sediment conduits are important components of the deep-water environment and are the main pathways for sediment transport from the shelf to the basin floor. Using 3-D and 2-D seismic reflection data, seismic facies and statistical morphometric analyses, this study showed the architectural evolution of five canyons, two slide scars and four gullies on the southern part of the Loppa High, Barents Sea. Morphometric parameters such as thalweg depth (lowest point on a conduit's base), wall depth (middle point), height, width and base width, sinuosity, thalweg gradient, aspect ratio (width/height) and cross-sectional area of the conduits were measured at intervals of 250-m perpendicular to the conduits' pathways. Our results show that the canyons and slide scars in the study area widen down slope, whereas the gullies are narrow and short with uniform widths. The sediment conduits in the study area evolved in three stages. The first stage is correlated with a time when erosion and bypass were dominant in the conduits, and sediment transferred to the basin in the south. The second stage occurred when basin subsidence was prevalent, and a widespread fine-grained sequence was deposited as a drape blanketing the canyons and other conduits. A final stage occurred when uplift and glacial erosion configured the entire southern Loppa High into an area of denudation. Our work demonstrates that the morphometric parameters of the canyons, slide scars and gullies generally have increasing linear trends with down-slope distance, irrespective of their geometries. The morphometric analysis of the sediment conduits in the study area has wider applications for understanding depositional processes, reservoir distribution and petroleum prospectivity in frontier basins.

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Submarine channel evolution, terrace development, and preservation of intra-channel thin-bedded turbidites: Mahin and Avon channels, offshore Nigeria

Cited by 81 publications

References 66 publications

Dispersion, Accumulation, and the Ultimate Fate of Microplastics in Deep-Marine Environments: A Review and Future Directions

Dispersion, Accumulation, and the Ultimate Fate of Microplastics in Deep-Marine Environments: A Review and Future Directions

Quantifying the geomorphic response of modern submarine channels to actively growing folds and thrusts, deep-water Niger Delta

Morphometric analysis of sediment conduits on a bathymetric high: Implications for palaeoenvironment and hydrocarbon prospectivity

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