Modelling subaqueous bipartite sediment gravity flows on the basis of outcrop constraints: first results

Tinterri, Roberto; Drago, Michele; Consonni, Alberto; Davoli, Giancarlo; Mutti, Emiliano

doi:10.1016/j.marpetgeo.2003.03.003

Cited by 57 publications

(35 citation statements)

References 48 publications

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“…Indeed it is not currently possible to compute appropriately resolved DNS schemes over length scales relevant to many field settings. Most previous modeling has assumed that direct particle interactions can be neglected, and hence that the flow is dilute, although there are exceptions (e.g., Tinterri et al 2003). Key areas of uncertainty are how sediment is transported close to the bed, and how it is eroded and resuspended.…”

Section: (F) Signal Shredding and The Tempo Of Sediment Transportmentioning

confidence: 99%

Key Future Directions For Research On Turbidity Currents and Their Deposits

Talling

Allin

Armitage

et al. 2015

Journal of Sedimentary Research

163

117

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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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Section: (F) Signal Shredding and The Tempo Of Sediment Transportmentioning

confidence: 99%

Key Future Directions For Research On Turbidity Currents and Their Deposits

Talling

Allin

Armitage

et al. 2015

Journal of Sedimentary Research

163

117

View full text Add to dashboard Cite

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“…Concerning the first issue, there seems to be a consensus that many turbidity currents are generated by debris flows, yet very little work has been done to quantify this process and to understand and model the downstream variation of deposit composition (Drago, 2002;Tinterri et al, 2003). Laboratory experiments with sand-rich sediment mixtures combining the experimental techniques of Mohrig and Marr (2003) with those described here should be very fruitful for understanding the relevant processes in turbidity-current formation and for scaling the results from the laboratory to the continental margin.…”

Section: Introductionmentioning

confidence: 99%

Emerging insights into the dynamics of submarine debris flows

Elverhøi¹,

Issler

Blasio

et al. 2005

Nat. Hazards Earth Syst. Sci.

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Recent experimental and theoretical work on the dynamics of submarine debris flows is summarized. Hy-droplaning was first discovered in laboratory flows and later shown to likely occur in natural debris flows as well. It is a prime mechanism for explaining the extremely long runout distances observed in some natural debris flows even of over-consolidated clay materials. Moreover, the accelerations and high velocities reached by the flow head in a short time appear to fit well with the required initial conditions of observed tsunamis as obtained from back-calculations. Investigations of high-speed video recordings of laboratory debris flows were combined with measurements of total and pore pressure. The results are pointing towards yet another important role of ambient water: Water that intrudes from the water cushion underneath the hydroplaning head and through cracks in the upper surface of the debris flow may drastically soften initially stiff clayey material in the "neck" of the flow, where significant stretching occurs due to the reduced friction at the bottom of the hydroplaning head. This self-reinforcing process may lead to the head separating from the main body and becoming an "outrunner" block as clearly observed in several natural debris flows. Comparison of laboratory flows with different material composition indicates a gradual transition from hydroplaning plug flows of stiff clay-rich material, with a very low suspension rate, to the strongly agitated flow of sandy materials that develop a pronounced turbidity current. Statistical analysis of the great number of distinguishable lobes in the Storegga slide complex reveals power-law scaling behavior of the runout distance with the release mass over many orders of magnitude. Mathematical flow models based on viscoplastic material behavior (e.g. BING) successfully reproduce the observed scaling behavior only for relatively small clay-rich debris flows while granular (frictional) models fail at all scales. For very large release masses, hydroplan-ing or significant softening of the shear layer due to water in-Correspondence to: A. Elverhøi (anders.elverhoi@geo.uio.no) corporation must be invoked to recover the observed scaling behavior; a combination of both effects likely will give the most realistic description of the phenomenon. Detailed studies of the neck behavior and the compositional dependence of the material properties are needed to arrive at a quantitative model. Other related and important open questions concern the rheological model appropriate for sandy debris flows and the suspension rate from the dense body into the associated turbidity current.

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“…Mutti et al 2003;Tinterri et al 2003) with debrisflow deposit at the base, and with superincumbent thick finely structured sandstone/siltstone facies resulting from turbulent portions of the flow. Individually placed megaturbidites probably represent the more distal equivalents of the complex beds and reflect uninterrupted deposition from turbulent flows.…”

Section: Resultsmentioning

confidence: 99%

“…Disorganized pebbly mudstone facies and massive conglomerates (debris-flow deposits or debrites) at the base of thick sandy/silty beds characterized by a fining upward facies sequence (turbulent portions of the flow) are referred to as highly efficient bipartite flows (e.g. Mutti et al 2003;Tinterri et al 2003) in which sharp grain-size breaks represent a variation in hydrodynamic conditions of the gravity flow during its downcurrent evolution.…”

Section: Interpretation Of the Orava Megabedsmentioning

confidence: 99%

Large-volume gravity flow deposits in the Central Carpathian Paleogene Basin (Orava region, Slovakia): evidence for hyperpycnal river discharge in deep-sea fans

Stárek¹,

Soták²,

Jablonský³

et al. 2013

Geologica Carpathica

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Abstract:The deep-water clastic systems of the Central Carpathian Paleogene Basin contain megabeds, which are developed in distinctive stratigraphic horizons and can be traced over long distances. These beds are characterized by great individual thickness (4-13 m), uniform lithology and internal structures. On the basis of their lithology, sedimentary structures and sequence development, the megabeds are characterized by 15 individual facies and interpreted from the viewpoint of flow hydrodynamics. The grain-size distribution and internal structures of the megabeds point to their deposition from uniform turbulent flows. The main controlling factor for generation of such large voluminous flows is inferred in the sea-level changes, when a relative rising of sea level during the Eocene/Oligocene boundary was responsible for long-lasting accumulation of the clastic supply at the basin margins. The large volume of detritus from river discharge and ravinement surfaces of flooded land was accumulated on the shore and in the conduit heads where the sediment was remobilized by other triggers. The flows generated by catastrophic floods during the early Rupelian sea-level lowstand are thought to be the most probably triggering mechanism. The large highly erosive hyperpycnal flows from flooding rivers could erode accumulated deposits in the conduit or on steeper basin-margin slopes and could cause progressive increase of the sand volume in the flow. Conduit flushing appears to be the most probable source of sediment for the very large voluminous flows that were responsible for deposition of the Orava megabeds.

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Modelling subaqueous bipartite sediment gravity flows on the basis of outcrop constraints: first results

Cited by 57 publications

References 48 publications

Key Future Directions For Research On Turbidity Currents and Their Deposits

Key Future Directions For Research On Turbidity Currents and Their Deposits

Emerging insights into the dynamics of submarine debris flows

Large-volume gravity flow deposits in the Central Carpathian Paleogene Basin (Orava region, Slovakia): evidence for hyperpycnal river discharge in deep-sea fans

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