Geomorphology of the Talismán Slide (Western slope of Hatton Bank, NE Atlantic Ocean)

Sayago-Gil, M.; Long, David A.; Fernández-Salas, L.M.; Hitchen, K.; López-González, N.; Díaz‐del‐Río, V.; Durán-Muñoz, P.

doi:10.1007/978-90-481-3071-9_24

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…Bottom currents are able to generate erosion at the seabed causing an increase in steepness of the slope and hence favouring failure (Sayago‐Gil et al, 2010; Tournadour et al, 2015). This triggering factor cannot be discounted in the Namibian margin where contourites and associated channel complexes are ubiquitous in the Cenozoic slopes (Figure 4b).…”

Section: Discussion—control Of Margin Architecture On Slope Processes...mentioning

confidence: 99%

Regional assessment of gravity‐driven deformation offshore Namibia (West Africa)—Styles, distribution and controlling factors

2022

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This paper presents a semi‐quantitative analysis of gravity‐driven deformation along the Namibian margin using extensive 2D depth converted seismic data. The geometries, internal characters and distribution of gravity‐driven systems were investigated through regional and detailed seismic studies. The research shows that surficial slumps are typically ca. 50 m thick and are characterised by contorted seismic facies commonly occurring along the slopes of the margin. They commonly funnel and cluster within high relief areas such as canyons and pre‐existing landslide scars. These contrast with coherent slides that are up to 2 km thick which extend laterally along the margin for tens to hundreds of kilometres. Slides preferentially occur in the proximal part of the margin and are constrained within the main margin depocenters. Here, high sedimentation rates and loading promote the generation of distinct, weak, overpressured layers that favour initiation of sliding of relatively coherent sediment masses. This research also shows that one‐third of volume of the post‐rift sediments on the Namibian margin were affected by slides and slumps. This demonstrates that gravity‐driven deformation is a key geological process that can strongly modify the evolution of rifted passive margins.

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Section: Discussion—control Of Margin Architecture On Slope Processes...mentioning

confidence: 99%

Regional assessment of gravity‐driven deformation offshore Namibia (West Africa)—Styles, distribution and controlling factors

2022

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“…Hovland et al (2002) concluded that elongation of pockmarks occurs in areas influenced by bottom currents that are capable of reshaping the pockmark morphology. Consequently, we suggest that the oceanographic activities in the study area associated with strong bottom currents are important processes that can sculpt the seafloor and pre-existing seafloor morphologies, creating both erosional and depositional morphologies (e.g., Masson et al, 2004, Sayago-Gil et al, 2010Schattner et al, 2016). The seafloor in the present study area lies within a water depth of 800 -2400 m, which coincides with the depth of influence of two counter-currents, the Antarctic Intermediate Water (AAIW) and North Atlantic Deep Water (NADW) oceanic currents (Weigelt and Uenzelmann-Neben, 2004; Figures 1 and 7).…”

Section: Origin Of Pockmarks and Other Seafloor Depressionsmentioning

confidence: 99%

Evolution of seafloor pockmarks along the Northern Orange Basin, Offshore South Africa: Interplay between fluid flow and bottom current activities

Eruteya¹,

Dominick²,

Niyazi³

et al. 2021

Preprint

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Pockmarks are pervasive geomorphologic features identified along continental margins resulting from fluid expulsion on the seafloor. However, the understanding of the underlying geological mechanism/control in relation to their evolution, distribution, and morphology is limited, especially along data-starved continental margins such as the Northern Orange Basin. Analysis of a high-quality 3D seismic reflection data reveals at least 50 individual pockmarks, two channel-like depressions and several irregular depressions in water depth ranging between 800 m and 2400 m. Morphologically, the pockmarks are circular, elongated, comet-like and crescentic in shape, with diameters and depths ranging between ∼0.2 - 2.8 km and ∼10 - 130 m, respectively. Preferential alignment of these pockmarks on the seafloor in relation to the axis of underlying turbidite channels, erosional morphologies and mass transport complexes portray a genetic relationship. The slope architecture hints at the possibility of both deep and shallow fluid source driving pockmark formation. Under this scenario, deep thermogenic gas derived from Cretaceous source rocks migrated along fault systems associated with the Late Cretaceous Megaslide complex to the overburden. The fluids are stored/redistributed in contourite and turbidite channels and subsequently focused toward the seafloor under an increased pore pressure regime. Yet, the fluids may be either solely biogenic gas or heterogeneous, incorporating biogenic components and pore-water derived from the channels and dewatering of the contourites. Importantly, the discovery of crescentic and elongated end-member pockmark morphologies indicate post-formation sculpting of the initial pockmark morphologies by bottom currents. The discovery of these deep-water pockmarks opens the possibility that such fluid escape features may be more widespread than currently documented in the Northern Orange Basin. This has implications in understanding of the petroleum system here and their potential role in the South Atlantic marine ecosystems and global climate change in terms of the expulsion of climate forcing gases.

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“…The study of seafloor morphology and recent subsurface stratigraphic units can be used to infer regional patterns of bottom-water dynamics (e.g., Due et al, 2006;MacLachlan et al, 2008;Sayago-Gil et al, 2010).…”

Section: Regional Oceanographic Processes Inferred From Deepwater Sed...mentioning

confidence: 99%

“…The combined interpretation of geological and oceanographic processes sheds light on local-to-regional patterns of bottom-flow dynamics (Hernández-Molina et al, 2003;Hanquiez et al, 2007), their spatial (MacLachlan et al, 2008) and temporal variability (Breitzke et al, 2017), and sediment transport pathways (Sayago-Gil et al, 2010). Such information is essential for constraining thermohaline circulation at local and regional scales (Wiles et al, 2014) and discerning the role of other controlling mechanisms, such as tectonic Journal Pre-proof J o u r n a l P r e -p r o o f 3 activity or the topographic setting (e.g., Mulder et al, 2003;Due et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Geomorphology of Ona Basin, southwestern Scotia Sea (Antarctica): Decoding the spatial variability of bottom-current pathways

et al. 2020

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Geomorphology of the Talismán Slide (Western slope of Hatton Bank, NE Atlantic Ocean)

Cited by 5 publications

References 15 publications

Regional assessment of gravity‐driven deformation offshore Namibia (West Africa)—Styles, distribution and controlling factors

Regional assessment of gravity‐driven deformation offshore Namibia (West Africa)—Styles, distribution and controlling factors

Evolution of seafloor pockmarks along the Northern Orange Basin, Offshore South Africa: Interplay between fluid flow and bottom current activities

Geomorphology of Ona Basin, southwestern Scotia Sea (Antarctica): Decoding the spatial variability of bottom-current pathways

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