Detailed seismic-reflection and sedimentary study of turbidite sediment waves on the Var Sedimentary Ridge (SE France): significance for sediment transport and deposition and for the mechanisms of sediment-wave construction

Migeon, Sébastien; Savoye, Bruno; Zanella, Elena; Mulder, Thierry; Faugères, Jean-Claude; Weber, O.

doi:10.1016/s0264-8172(00)00060-x

Cited by 146 publications

(162 citation statements)

References 30 publications

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“…7), becoming parallel and continuous in seaward direction. The wavy facies is similar to undulations observed on continental shelves and slopes, interpreted by many authors as bedforms (sediment waves: Migeon et al, 2001;Lee et al, 2002) or deformation structures evolving into depositional bedforms (Cattaneo et al, 2004). They have a spacing of about 300 m, an average height of 1.5 to 2 m and with a thinning of the seaward dipping limb.…”

Section: Chirp Data (Figs 4 6 and 7)supporting

confidence: 76%

Shoreface migrations at the shelf edge and sea-level changes around the Last Glacial Maximum (Gulf of Lions, NW Mediterranean)

et al. 2006

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The Bourcart-Hérault canyon interfluve in the Gulf of Lions (NW Mediterranean) was the site of very high sedimentation (up to 2.5 m/kyr) around the Last Glacial Maximum, due to the vicinity of major fluvial systems that fed the shelf edge. Shoreface deposits and offshore muds deposited during each glacial/interglacial 100 kyr-cycle, created a repeated motif with highangle and low-angle clinoforms on seismic profiles. New detailed morphological, sedimentological and paleo-environmental data, constrained by 14 C dating, allow us to propose a scenario for the evolution of this critical area between 46 and 15 cal. kyr BP. The major seismic sequence (S5), formed as a forced regression during the overall sea-level fall between MIS-3 and MIS-2, can be sub-divided into several prograding units, which indicate that relative sea-level changes were punctuated by intervals of increased fall or slow-down, or even stillstand. Similarly, the onset of sea-level rise was marked by steps, during which wave-

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Section: Chirp Data (Figs 4 6 and 7)supporting

confidence: 76%

Shoreface migrations at the shelf edge and sea-level changes around the Last Glacial Maximum (Gulf of Lions, NW Mediterranean)

et al. 2006

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“…2C, 5C;Paull et al 2010a;Covault et al 2014), and on levees of deep-water channel systems ( Fig. 5B; Migeon et al 2001;Normark et al 2002;Fildani and Normark 2004;Armitage et al 2012).…”

Section: (B) Supercritical-flow Dynamics and Depositsmentioning

confidence: 97%

Key Future Directions For Research On Turbidity Currents and Their Deposits

Talling

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Armitage

et al. 2015

Journal of Sedimentary Research

166

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Turbidity currents, and other types of submarine sediment density flow, redistribute more sediment across the surface of the Earth than any other sediment flow process, yet their sediment concentration has never been measured directly in the deep ocean. The deposits of these flows are of societal importance as imperfect records of past earthquakes and tsunamogenic landslides and as the reservoir rocks for many deep-water petroleum accumulations. Key future research directions on these flows and their deposits were identified at an informal workshop in September 2013. This contribution summarizes conclusions from that workshop, and engages the wider community in this debate. International efforts are needed for an initiative to monitor and understand a series of test sites where flows occur frequently, which needs coordination to optimize sharing of equipment and interpretation of data. Direct monitoring observations should be combined with cores and seismic data to link flow and deposit character, whilst experimental and numerical models play a key role in understanding field observations. Such an initiative may be timely and feasible, due to recent technological advances in monitoring sensors, moorings, and autonomous data recovery. This is illustrated here by recently collected data from the Squamish River delta, Monterey Canyon, Congo Canyon, and offshore SE Taiwan. A series of other key topics are then highlighted. Theoretical considerations suggest that supercritical flows may often occur on gradients of greater than , 0.6u. Trains of up-slope-migrating bedforms have recently been mapped in a wide range of marine and freshwater settings. They may result from repeated hydraulic jumps in supercritical flows, and dense (greater than approximately 10% volume) near-bed layers may need to be invoked to explain transport of heavy (25 to 1,000 kg) blocks. Future work needs to understand how sediment is transported in these bedforms, the internal structure and preservation potential of their deposits, and their use in facies prediction. Turbulence damping may be widespread and commonplace in submarine sediment density flows, particularly as flows decelerate, because it can occur at low (, 0.1%) volume concentrations. This could have important implications for flow evolution and deposit geometries. Better quantitative constraints are needed on what controls flow capacity and competence, together with improved constraints on bed erosion and sediment resuspension. Recent advances in understanding dilute or mainly saline flows in submarine channels should be extended to explore how flow behavior changes as sediment concentrations increase. The petroleum industry requires predictive models of longer-term channel system behavior and resulting deposit architecture, and for these purposes it is important to distinguish between geomorphic and stratigraphic surfaces

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“…With typical wavelengths of O(1-10 km) and heights up to O(100 m) (Wynn et al 2000a;Migeon et al 2001;Nakajima & Satoh 2001;Normark et al 2002;Wynn & Stow 2002), they represent one of the most comprehensively documented bedforms, with the first descriptions dating back to the 1950s (Heezen, Tharp & Ewing 1959). More recently, a considerable amount of data has been acquired largely as a result of the growth in hydrocarbon exploration in deep-water systems.…”

Section: Introductionmentioning

confidence: 99%

“…Bottom current waves can be oblique or parallel to the flow, depending on how strongly they are influenced by the Coriolis force (Normark et al 1980). Sediment waves are frequently observed to migrate in the upstream direction (Lonsdale & Hollister 1979), with downstream migration documented in a few cases (Migeon et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Deep-water sediment wave formation: linear stability analysis of coupled flow/bed interaction

et al. 2011

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A linear stability analysis is carried out for the interaction of an erodible sediment bed with a sediment-laden, stratified flow above the bed, such as a turbidity or bottom current. The fluid motion is described by the full, two-dimensional Navier-Stokes equations in the Boussinesq approximation, while erosion is modelled as a diffusive flux of particles from the bed into the fluid. The stability analysis shows the existence of both Tollmien-Schlichting and internal wave modes in the stratified boundary layer. For the internal wave mode, the stratified boundary layer acts as a wave duct, whose height can be determined analytically from the Brunt-Väisäläf r e q u e n c y criterion. Consistent with this criterion, distinct unstable perturbation wavenumber regimes exist for the internal wave mode, which are associated with different numbers of pressure extrema in the wall-normal direction. For representative turbidity current parameters, the analysis predicts unstable wavelengths that are consistent with field observations. As a key condition for instability to occur, the base flow velocity boundary layer needs to be thinner than the corresponding concentration boundary layer. For most of the unstable wavenumber ranges, the phase relations between the sediment bed deformation and the associated wall shear stress and concentration perturbations are such that the sediment waves migrate in the upstream direction, which again is consistent with field observations.

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Detailed seismic-reflection and sedimentary study of turbidite sediment waves on the Var Sedimentary Ridge (SE France): significance for sediment transport and deposition and for the mechanisms of sediment-wave construction

Cited by 146 publications

References 30 publications

Shoreface migrations at the shelf edge and sea-level changes around the Last Glacial Maximum (Gulf of Lions, NW Mediterranean)

Shoreface migrations at the shelf edge and sea-level changes around the Last Glacial Maximum (Gulf of Lions, NW Mediterranean)

Key Future Directions For Research On Turbidity Currents and Their Deposits

Deep-water sediment wave formation: linear stability analysis of coupled flow/bed interaction

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