Sediment distribution and evolution of sedimentary processes in a small sandy turbidite system (Golo system, Mediterranean Sea): implications for various geometries based on core framework Auteur(s) : Gervais, A Mulder, T Savoye, Bruno Gonthier, E Éditeur(s) : Springer Résumé : The Golo Margin in eastern Corsica is dissected by four canyons and two gullies which fed turbidite systems. Study of the dispersal of surficial sediments and flow dynamic in the Golo system is based on Kullenberg and interface cores interpreted in relation to a previously published seismic dataset. Cores were described in detail and interpreted within a sedimentary and stratigraphic framework. During the last 42,000 years, gravity processes which occurred in the large systems with a canyon source were mainly slide-induced, differentiated turbulent surges and hyperpycnal flows. Processes occurring in the small system with a gully source are mainly hyperconcentrated and concentrated flows. Deposits from the Corsican Margin can intercalate with products of processes triggered on the Pianosa Ridge located in the eastern part of the basin. During relative sea-level lowstands or during periods of rapid or high-amplitude sea-level fall, only large canyons (South and North Golo) are supplied by carbonate-rich hyperconcentrated and concentrated flows which are channelled in incised valleys on the shelf. During periods of slow or low-amplitude sea-level fall and during sea-level rise, sediments are trapped on a shelf delta and intensely winnowed by shelf hydrodynamic processes. Sand-rich hyperconcentrated and concentrated flows occur. All the systems fed by a canyon are active simultaneously. Gullies form and are active only during periods of sea-level rise. During relative highstands of sea level (Holocene), all the system is draped by hemipelagic sediments. Relative sea-level changes and canyon location relative to river mouths have a strong influence on the nature of sediment input, and the initiation and type of gravity flows which, in turn, control morphology and geometry. Geo-Marine Letters (0276-0460) (Springer), 2006-12 , Vol. 26 , N. 6 , P. 373-395 Droits : 2006 Springer http://archimer.ifremer.fr/doc/2006/publication-3594.pdf DOI:10.1007/s00367-006-0045-z http://archimer.ifremer.fr/doc/00000/3594/ | Partager |
Late Quaternary deep-sea sedimentation in the western Black Sea: New insights from recent coring and seismic data in the deep basin Auteur(s) : Lericolais, Gilles Bourget, Julien Popescu, Irina Jermannaud, Paul Mulder, T. Jorry, Stephan Panin, N. Éditeur(s) : Elsevier Science Bv Résumé : The Danube River Basin–Black Sea area represents a unique natural laboratory for studying the interplay between lithosphere and surface as well as source to sink relationships and their impact on global change. This paper addresses some information on the “active sink” of the system; i.e. the Danube deep sea fan and the Black Sea basin. The present study focuses on the distal sedimentary processes and the evolution of sedimentation since the Last Glacial Maximum. This is investigated through recently acquired long piston coring and shallow seismic data recovered at the boundary of influence of the distal part of the Danube turbidite system (to the north-west) and the Turkish margin (to the south). This dataset provides a good record of the recent changes in the sedimentary supply and climato-eustasy in the Black Sea region during the last 25 ka. This study demonstrates that the deep basin deposits bear the record of the Late Quaternary paleoenvironmental changes and that the western Black Sea constitutes an asymmetric subsident basin bordered by a northern passive margin with confined, mid-size, mud-rich turbidite systems mainly controlled by sea-level, and a southern turbidite ramp margin, tectonically active. Highlights ► Oceanographic results from survey carried out in the western Black Sea are presented. ► The Danube fan distal part: the Black Sea main depositional feature is described. ► This study is on the morphology and gravity sedimentation in the Black Sea deep basin. ► Data were collected at the boundary between the Danube fan and the Turkish margin. ► The dataset provide a good record of sedimentary supply and climato-eustatic changes. Global And Planetary Change (0921-8181) (Elsevier Science Bv), 2013-04 , Vol. 103 , P. 232-247 Droits : 2012 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/00095/20637/18272.pdf DOI:10.1016/j.gloplacha.2012.05.002 http://archimer.ifremer.fr/doc/00095/20637/ | Partager |