Breaching the Shelfbreak: Passage From Youthful to Mature Phase in Submarine Canyon Evolution

Farre, John A.; McGregor, Bonnie A.; Ryan, William B. F.; Robb, James M.

doi:10.2110/pec.83.06.0025

Cited by 112 publications

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“…11d); in proximal areas, the acoustically-transparent deposits failed along a common basal layer. Because older mass-transport deposits do not extent upslope of the youngest headscarp, it is conceivable that in this area failures propagated upslope in a retrogressive style, in a fashion similar to that described by Twichell and Roberts (1982), Farre et al (1983), and Pratson and Coakley (1996).…”

Section: Northern Areamentioning

confidence: 85%

Evidence of slope instability in the Southwestern Adriatic Margin

Minisini

Trincardi

Asioli

2006

Nat. Hazards Earth Syst. Sci.

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Abstract. The Southwestern Adriatic Margin (SAM) shows evidence of widespread failure events that generated slide scars up to 10 km wide and extensive slide deposits with run out distances greater than 50 km. Chirp-sonar profiles, side-scan sonar mosaics, multibeam bathymetry and sediment cores document that the entire slope area underwent repeated failures along a stretch of 150 km and that masstransport deposits, covering an area of 3320 km 2 , are highly variable ranging from blocky slides to turbidites, and lay on the lower slope and in the basin. The SAM slope between 300-700 m is impacted by southward bottom currents shaping sediment drifts (partly affected by failure) and areas of dominant erosion of the seafloor. When slide deposits occur in areas swept by bottom currents their fresh appearence and their location at seafloor may give the misleading impression of a very young age. Seismic-stratigraphic correlation of these deposits to the basin floor, however, allow a more reliable age estimate through sediment coring of the post-slide unit. Multiple buried failed masses overlap each other in the lower slope and below the basin floor; the most widespread of these mass-transport deposits occurred during the MIS 2-glacial interval on a combined area of 2670 km 2 . Displacements affecting Holocene deposits suggest recent failure events during or after the last phases of the last postglacial eustatic rise. Differences in sediment accumulation rates at the base or within the sediment drifts and presence of downlap surfaces along the slope and further in the basin may provide one or multiple potential weak layers above which widespread collapses take place. Neotectonic activity and seismicity, together with the presence of a steep slope, represent additional elements conducive to sediment instability and failure along the SAM. Evidence of large areas still prone to failure provides elements of tsunamogenic hazard.

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Section: Northern Areamentioning

confidence: 85%

Evidence of slope instability in the Southwestern Adriatic Margin

Minisini

Trincardi

Asioli

2006

Nat. Hazards Earth Syst. Sci.

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“…The steep gradients of the slope and its convex-up geometry likely favoured the development of landslides along the lower slope, incising the Plio-Quaternary deposits and retrograding towards the shelf-margin. Once retrograding canyons breach the shelf-margin, the interaction with sedimentary fluxes along the shelf could have induced the creation of turbidity currents (Farre et al, 1983) and the maintenance of the axial incision along the canyons in concurrent top-down and bottomup scenarios. Older incisions along the foot of the slope were progressively buried by unconsolidated mass-wasting deposits resulting from the subsequent bottom-up erosion of the PlioQuaternary slope deposits.…”

Section: Palermo Canyonsmentioning

confidence: 99%

Submarine canyons of north-western Sicily (Southern Tyrrhenian Sea): Variability in morphology, sedimentary processes and evolution on a tectonically active margin

Iacono

Sulli

Agate

2014

Deep Sea Research Part II: Topical Studies in Oceanography

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a b s t r a c tSwath-bathymetry, mono-channel and multi-channel seismic reflection records acquired during the last two decades on the northern Sicilian margin have unveiled a dense network of submarine canyons within the depth range of 80-2100 m. The canyons display a relevant variability in their geometry, morphology and sedimentary processes. The margin shows a young, tectonically active shelf to slope setting, linking the Sicilian-Maghrebian Thrust Belt to the Tyrrhenian oceanic realm, developed during the Neogene-Quaternary time span. The aim of this study is to highlight the main governing factors that contributed to the evolution and differentiation of the northern Sicilian canyons, mainly focusing on the Gulf of Palermo and on the Gulf of Castellammare. Tectonic control is more evident in the canyons of the Gulf of Palermo, with submarine landslides retrograding on a steep slope and mainly controlling their evolution. Otherwise, canyons, tributaries and gullies mapped in the Gulf of Castellammare developed on a less steep substrate and display sinuous to meandering paths, with a relevant role of coastal/shelf sedimentary inputs and downslope turbidity processes in their formation. Results suggest that, despite the geographically close proximity of the two study areas, the different structural settings of the Castellammare and Palermo Basins are mainly responsible for canyon variability. Data indicate likely ongoing uplift and tilting movements along the Sicilian margin, influencing the development of the studied canyons, which have probably been more active during the Quaternary glacial maxima than they are in the present day.

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“…This proves that the Pearl River has been the sedimentary source for the Pearl River Delta on the continent shelf for a long time, as well as the continental slope area. Sea level change is another important factor to consider, since relative sea level changes are responsible for the location at which sediment input from onshore rivers is deposited (Farre et al 1983). During highstands, the head of the Pearl River Canyon is separated from the coastline by a wide shelf.…”

Section: High Sediment Inputmentioning

confidence: 99%

“…Submarine canyons are common features incised into the continental shelves and slopes of all continental margins worldwide (Farre et al 1983;Hagen et al 1996;Klaus and Taylor 1991;Puig et al 2003;Deptuck et al 2003;Harris and Whiteway 2011). Most canyons are located entirely on the upper slope, although there are also some large canyons with heads that deeply indent the shelf break.…”

Section: Introductionmentioning

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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Breaching the Shelfbreak: Passage From Youthful to Mature Phase in Submarine Canyon Evolution

Cited by 112 publications

References 0 publications

Evidence of slope instability in the Southwestern Adriatic Margin

Evidence of slope instability in the Southwestern Adriatic Margin

Submarine canyons of north-western Sicily (Southern Tyrrhenian Sea): Variability in morphology, sedimentary processes and evolution on a tectonically active margin

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

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