GEOSCAN, résultats de la recherche


TitreKey future directions for research on turbidity currents and their deposits
AuteurTalling, P J; Allin, J; Armitage, D A; Arnott, R W C; Cartigny, M J B; Clare, M A; Felletti, F; Covault, J A; Girardclos, S; Hansen, E; Hill, P R; Hiscott, R N; Hogg, A J; Hughes Clarke, J; Jobe, Z R; Malgesini, G; Mozzato, A; Naruse, H; Parkinson, S; Peel, F J; Piper, D J W; Pope, E; Postma, G; Rowley, P; Sguazzini, A; Stevenson, C J; Sumner, E J; Sylvester, Z; Watts, C; Xu, J
SourceJournal of Sedimentary Research vol. 85, 2015 p. 153-169, (Accès ouvert)
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130325
ÉditeurSociety for Sedimentary Geology
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceRégion extracotière de l'ouest
Lat/Long OENS-124.0000 -123.0000 50.0000 49.0000
Lat/Long OENS-126.0000 -121.0000 37.0000 34.0000
Sujetscourants de turbidite; sédimentation turbiditique; courants; topographie du fond océanique; deltas; turbidites; configurations lit; érosion; canyons sous-marins; glissements de terrain; transport sous-marin; transport des sediments; établissement de modèles; géologie marine; sédimentologie
ProgrammeGéo-risques marins, Géoscience pour la sécurité publique
Diffusé2015 02 16
Résumé(disponible en anglais seulement)
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 in seismic datasets. Validation of models, including against full-scale field data, requires clever experimental design of physical models and targeted field programs.
Résumé(Résumé en langage clair et simple, non publié)
Voici un résumé des besoins futurs en matière de recherche sur les courants de turbidité découlant d'un atelier offert en septembre 2013. Il encourage, entre autres, la réalisation de travaux sur les débits des deltas Squamish et Fraser.