Morphology, seismic characteristics and development of Cap Timiris Canyon, offshore Mauritania: A newly discovered canyon preserved-off a major arid climatic region

Antobreh, A.A.; Krastel, Sebastian

doi:10.1016/j.marpetgeo.2005.06.003

Cited by 112 publications

(77 citation statements)

References 44 publications

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“…Sediment gravity flows, predominantly turbidity currents, sculpt the seafloor by erosion and deposition into dramatic seascapes, including deeply incised submarine canyons (Paull et al, 2011), sinuous submarine channels with numerous meander cutoffs (Antobreh and Krastel, 2006;Kolla et al, 2012), and submarine fans consisting of lobes and distributary channels (Deptuck et al, 2008;Jegou et al, 2008). The architecture of these depositional systems is strongly influenced by the input grain-size distribution (e.g., sand-rich vs. mud-rich systems of Reading and Richards, 1994).…”

Section: Introductionmentioning

confidence: 99%

Rapid Adjustment of Submarine Channel Architecture To Changes In Sediment Supply

Jobe¹,

Sylvester²,

Parker³

et al. 2015

Journal of Sedimentary Research

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Changes in sediment supply and caliber during the last ~130 ka have resulted in a complex architectural evolution of the Y channel system on the western Niger Delta slope. This evolution consists of four phases, each with documented or inferred changes in sediment supply. Phase 1 flows created wide (1,000 m), low-sinuosity (1.1) channel forms with lateral migration and little to no aggradation. During Phase 2, the Y channel system began to aggrade, creating more narrow (300 m) and sinuous (1.4) channel forms with many meander cutoffs. This system was abandoned at ~ 130 ka, perhaps related to rapid relative sea-level rise during MIS (Marine Isotope Stage) 5. Phase 3 flows were mud-rich and deposited sediment on the outer bends of the channel form, resulting in the narrowing (to 250 m), straightening (to a sinuosity of 1.22), and aggradation of the Y channel system. Renewed influx of sand into the Y channel system occurred with Phase 4 at ~ 50 ka, during MIS 3 sea-level fall. The onset of Phase 4 is marked by the initiation of the Y′ tributary channel, which re-established sand deposition in the Y channel system. Flows entering the Y channel from the Y′ channel were underfit, resulting in inner levee deposition that is most prevalent on outer banks, acting to further straighten (1.21) and narrow (to 200 m wide) the Y channel. The inner levees accumulated quickly as the flows sought equilibrium, with deposition rates > 200 cm/ky. Marked by the presence of the last sand bed, abandonment occurred at ~19 ka in the Y channel and ~15 ka in the Y′ channel and is likely related to progressive abandonment due to shelf-edge delta avulsion and/or progressive sea level rise associated with Melt Water Pulse 1-A. The muddy, 5-meter-thick Holocene layer has thickness variations that mimic those seen in the sandy part of Phase 4, suggesting that dilute, muddy flows continue to affect the modern Y channel system. This unique dataset allows us to unequivocally link changes in submarine channel architecture to variations in sediment supply and caliber. Changes in the updip sediment routing system (i.e. the channel "plumbing") are shown to have profound implications for submarine channel architecture and reservoir connectivity.

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Section: Introductionmentioning

confidence: 99%

Rapid Adjustment of Submarine Channel Architecture To Changes In Sediment Supply

Jobe¹,

Sylvester²,

Parker³

et al. 2015

Journal of Sedimentary Research

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“…Tributaries, multiple thalwegs, a V-shaped cross section, terraces, and scalloped, slumped edges are other characteristic features of Type I canyons ( Fig. 1; Shepard and Emery, 1973;Shepard, 1981;Gervais et al, 2004;Bertoni and Cartwright, 2005;Cunningham et al, 2005;Antobreh and Krastel, 2006;Lastras et al, 2009;Mountjoy et al, 2009;Armitage, et al, 2010). Many are associated with areas of high sediment supply (Weaver et al, 2000), such as coastal mountain belts (Gervais et al, 2004), large fluvial systems (Burke, 1972;Shepard and Emery, 1973;Shepard, 1981;McGregor et al, 1982;McHargue and Webb, 1986;O'Connell et al, 1987;Green and Uken, 2008;Yu et al, 2009) or vigorous longshore drift cells (Moore, 1969;Burke, 1972;Inman et al, 1976;Paull et al, 2005;Covault et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Two fundamentally different types of submarine canyons along the continental margin of Equatorial Guinea

Jobe

Lowe

Uchytil

2011

Marine and Petroleum Geology

163

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Most submarine canyons are erosive conduits cut deeply into the world's continental shelves through which sediment is transported from areas of high coastal sediment supply onto large submarine fans. However, many submarine canyons in areas of low sediment supply do not have associated submarine fans and show significantly different morphologies and depositional processes from those of 'classic' canyons. Using three-dimensional seismic reflection and core data, this study contrasts these two types of submarine canyons and proposes a bipartite classification scheme.The continental margin of Equatorial Guinea, West Africa during the late Cretaceous was dominated by a classic, erosional, sand-rich, submarine canyon system. This system was abandoned during the Paleogene, but the relict topography was reactivated in the Miocene during tectonic uplift. A subsequent decrease in sediment supply resulted in a drastic transformation in canyon morphology and activity, initiating the 'Benito' canyon system. This non-typical canyon system is aggradational rather than erosional, does not indent the shelf edge and has no downslope sediment apron. Smooth, draping seismic reflections indicate that hemipelagic deposition is the chief depositional process aggrading the canyons. Intra-canyon lateral accretion 2 deposits indicate that canyon concavity is maintained by thick (> 150 m), dilute, turbidity currents. There is little evidence for erosion, mass wasting, or sand-rich deposition in the Benito canyon system. When a canyon loses flow access, usually due to piracy, it is abandoned and eventually filled. During canyon abandonment, fluid escape causes the successive formation of 'cross-canyon ridges' and pockmark trains along buried canyon axes.Based on comparison of canyons in the study area, we recognize two main types of submarine canyons: 'Type I' canyons indent the shelf edge and are linked to areas of high coarse-grained sediment supply, generating erosive canyon morphologies, sandrich fill, and large downslope submarine fans/aprons. 'Type II' canyons do not indent the shelf edge and exhibit smooth, aggradational morphologies, mud-rich fill, and a lack of downslope fans/aprons. Type I canyons are dominated by erosive, sandy turbidity currents and mass wasting, whereas hemipelagic deposition and dilute, sluggish turbidity currents are the main depositional processes sculpting Type II canyons. This morphology-based classification scheme can be used to help predict depositional processes, grain size distributions, and petroleum prospectivity of any submarine canyon.

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“…Relative sea level changes have also been argued as one of the critical factors controlling deposition patterns inside submarine canyons (Gingele et al 2004;Baztana et al 2005;Antobreh and Krastel 2006;Gong et al 2011). Eustatic changes in the South China Sea contributed to longterm repeated cut-and-fill events of varying magnitude of the Pearl River Canyon.…”

Section: High Sediment Inputmentioning

confidence: 99%

Morphotectonics and evolutionary controls on the Pearl River Canyon system, South China Sea

Ding

Li³

et al. 2013

Mar Geophys Res

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The Pearl River Canyon system is a typical canyon system on the northern continental slope of the South China Sea, which has significant implications for hydrocarbon exploration. Through swath bathymetry in the canyon area combined with different types of seismic data, we have studied the morphotectonics and controlling factors of the canyon by analyzing its morphology and sedimentary structure, as well as the main features of the continental slope around the canyon. Results show that the Pearl River Canyon can be separated into three segments with different orientations. The upper reach is NW-oriented with a shallowly incised course, whereas the middle and lower reaches, that are located mainly in the Baiyun Sag, have a broad U-shape and have experienced consistent deposition. Seventeen deeply-cut canyons have developed in the slope north of the Baiyun Sag, playing an important role in the sedimentary processes of the middle and lower reaches of the Pearl River Canyon. These canyons display both asymmetrical V-and U-shapes along their lengths. Numerous buried channels can be identified below the modern canyons with unidirectionally migrating stacking patterns, suggesting that the canyons have experienced a cyclic evolution with several cut and fill phases of varying magnitude. These long established canyons, rather than the upper reach of the Pearl River Canyon, are the main conduits for the transport of terrigenous materials to the lower slope and abyssal basin during lowstand stage, and have contributed to the formation of vertically stacked deep-water fans in the middle reach. Canyon morphology is interpreted as a result of erosive sediment flows. The Pearl River Canyon and the 17 canyons in the slope area north of the Baiyun Sag probably have developed since the Miocene. Cenozoic tectonics, sea level change and sediment supply jointly control the morphology and sedimentary structure. The middle and lower reaches of the Pearl River Canyon developed on the paleo-terrain of the Baiyun Sag, which has been a persistently rapid depositional environment, receiving most of the materials transported via the canyons.

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Morphology, seismic characteristics and development of Cap Timiris Canyon, offshore Mauritania: A newly discovered canyon preserved-off a major arid climatic region

Cited by 112 publications

References 44 publications

Rapid Adjustment of Submarine Channel Architecture To Changes In Sediment Supply

Rapid Adjustment of Submarine Channel Architecture To Changes In Sediment Supply

Two fundamentally different types of submarine canyons along the continental margin of Equatorial Guinea

Morphotectonics and evolutionary controls on the Pearl River Canyon system, South China Sea

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