Prolific deep-marine slope channels of the Nile Delta, Egypt

Samuel, Andy; Kneller, Ben; Raslan, Samir; Sharp, A.; Parsons, Cormac

doi:10.1306/1105021094

Cited by 189 publications

(176 citation statements)

References 27 publications

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“…Large slope valleys were suggested to be formed at the early stage of channel formation, with MTDs at their base (e.g., Samuel et al 2003;Mayall et al 2006;Macauley and Hubbard 2013). As mass-wasting events can be precursors of submarine channels, some of these valleys may be filled by debris-flow deposits and later modified by subsequent turbidity flows, which eroded MTDs downslope and deposited channel-fill deposits within the scars (Fig.…”

Section: A Mechanism For Channel Initiationmentioning

confidence: 99%

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

Qin

Alves

Constantine

et al. 2017

Journal of Sedimentary Research

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ABSTRACT:A Pliocene-Quaternary submarine channel system, influenced by a localized mass wasting, is investigated in this work using high-resolution 3D seismic data from offshore Espírito Santo Basin, SE Brazil. Three abandoned channels, a channel belt and an mass-transport deposit (MTD) are recognized in the channel system within a confluence region confined by salt diapirs. In this confluence region, the cross-sectional area (CSA) of the channel system can be up to 1.2 km 2 , i.e., 4 to 10 times larger than CSA in other parts of the channel system. Such significant changes in the architecture and morphology of the channel system resulted from the interaction between mass-wasting processes and turbidity flows. We postulate that a basal erosional scar was created by mass-wasting processes and was filled with an MTD. This basal scar was then used as a preferential pathway for turbidity flows, which were captured by its headwall and lateral margins. The interpreted data shows that the captured turbidity flows greatly widened the basal scar, but caused only small modifications in scar height. Part of the MTD within the basal scar was removed downslope by turbidity flows, and was replaced by channel-fill deposits. This paper shows a flow-capture process occurred in a confluence region on continental slope. Basal scars can capture turbidity flows and facilitate flow channelization, which is a key process for submarine-channel initiation. The replacement of MTD by channel-fill deposits has profound implications for reservoir volumes and net-to-gross ratios in channel systems and partly depends on the turbidity-flows properties, such as their erosive ability and frequency. The more erosive and frequent flows are captured by the basal scar, the larger is the accommodation space created for succeeding sand-prone turbidites.

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Section: A Mechanism For Channel Initiationmentioning

confidence: 99%

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

Qin

Alves

Constantine

et al. 2017

Journal of Sedimentary Research

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“…Valley is an architectural element of higher order than the channel (Samuel et al, 2003;Kolla, 2007;Janocko et al, 2013). It comprises the sub-surface valley fill and the channel belt (Fig.…”

Section: Terminologymentioning

confidence: 99%

“…The valley is formed by lateral migration and vertical stacking of a single channel element (e.g. Samuel et al, 2003;Deptuck et al, 2003;Babonneau et al, 2004;Kolla, 2007;Janocko et al, 2013), and has a composite erosional surface consisting of a valley base and adjacent valley walls (erosional fairway sensu Deptuck et al, 2003;Catterall et al, 2010; master erosion/incision surface sensu Gee et al, 2007; channel-belt erosion surface sensu Kane and Hodgson, 2011; bounding erosion surface sensu Hansen et al, 2015) (Fig. 2e).…”

Section: Terminologymentioning

confidence: 99%

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Quantitative seismic geomorphology of a submarine channel system in SE Brazil (Espírito Santo Basin): Scale comparison with other submarine channel systems

Qin

Alves

Constantine

et al. 2016

Marine and Petroleum Geology

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Detailed morphological analyses of a Pleistocene-Holocene submarine channel system in terms of its hierarchical framework, were carried out using a 3D seismic volume from offshore Espírito Santo, SE Brazil. The channel morphology shows marked variations, with five segments (Segments a to e) being identified along its full length. For example, the cross-sectional area of the channel decreases by a factor of 70 from Segment a to Segment c, and is then followed by a nearly four-fold increase from Segment c to Segment d. The significant changes in channel morphology relate to temporal and spatial variations in flow volume within the channel. In the same channel system, the valley reveals three distinct segments (Segments A to C), with similar aspect ratios but marked variations in morphology along the valley distance. Valley morphological changes are chiefly affected by erosional processes. Segment B is characterised by the largest valley-base width, valley width, and cross-sectional area compared to the other two segments. Valley enlargement in Segment B results from relatively high degrees of lateral channel migration and associated cut bank erosion, leading to the widening of the valley, especially the valley base. In Segment C, the valley is characterised by inner bank erosion in the form of shallow-seated mass failures, which only enlarged the upper part of the valley wall. The spatial variations in both channel and valley morphology documented here suggest an important role of local factors (e.g. salt diapirs, tributaries, overbank collapse) in the development of channel systems. Hence, the morphological analyses developed in this work provide an effective tool for studying channels and valleys on continental slopes around the world.

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“…In contrast to other fine-grained slope systems (e.g. the Nile Delta; Samuel et al 2003;Cross et al 2009), incision is not initiated at the Rubbish Dump system with the introduction of clastic sediment; rather it is underlain by a package of thick amalgamated sheet sandstones which thin and fine laterally away from the eastern Dump and are interpreted as frontal lobe deposits. The lobe is incised by two channel complexes; the eastern complex features low NTG heterogeneous sand/ siltstone channel-fills which stack aggradationally with a slight easterly trajectory and the younger western complex which is deeply entrenched and is infilled with high NTG channel-fills that stack vertically.…”

Section: Reservoir Modelling Of Low Sandstone Percentage Channel Systemsmentioning

confidence: 79%

Capturing stratigraphic and sedimentological complexity from submarine channel complex outcrops to digital 3D models, Karoo Basin, South Africa

Pringle

Brunt

Hodgson

et al. 2010

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Submarine slope channel-fills form complicated stratigraphy and lithofacies distributions through repeated phases of erosion and deposition. This provides a challenge to accurate 3D modelling, particularly in representing lithofacies transitions within sand-poor areas. In this paper, traditional (sedimentary logs, palaeocurrent measurements, architectural panels) and non-conventional technologies (Light Detection and Ranging; Ground Penetrating Radar) were integrated to quantitatively describe lithofacies distributions and sedimentary architectures from two large-scale outcrops, one base of slope, high sandstone content system (Unit B) and one from a mid-slope, more mixed lithology system (Unit C), in the Laingsburg Formation, Karoo Basin, South Africa.The workflow described in this study combines digital structural restoration and extrapolation of major stratigraphic surfaces, grouped palaeocurrents and architectural geometries observed at outcrop to create 3D digital models. The model was divided into zones along major stratigraphic discontinuities and populated using lithofacies associations that were adjusted for outcrop rugosity and palaeodispersal direction. Observed channel margin asymmetries, distribution of lithofacies and stacking patterns were all honoured in the digital models.The Unit C slope-channel system differs from many exposed submarine channels due to the low proportion of sandstone present within the infill. Thin-bedded channel margin lithofacies are preserved through the lateral stepping of channels and allow the correlation of stratigraphy from channel axis to margin and on to overbank areas. In the older, sandier Unit B base-of-slope system, the stratigraphic change in stacking pattern, channel aspect ratio, lithofacies of channel-fills and stratigraphic hierarchy were all captured. This research captured the architectural complexity observed at outcrop to generate more realistic models than could be constructed normally using limited subsurface data.

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Prolific deep-marine slope channels of the Nile Delta, Egypt

Cited by 189 publications

References 27 publications

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

Quantitative seismic geomorphology of a submarine channel system in SE Brazil (Espírito Santo Basin): Scale comparison with other submarine channel systems

Capturing stratigraphic and sedimentological complexity from submarine channel complex outcrops to digital 3D models, Karoo Basin, South Africa

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