Back to Search
Start Over
Direct sediment transfer from land to deep-sea: Insights into shallow multibeam bathymetry at La Réunion Island
- Source :
- Marine Geology, Marine Geology, 2013, 346, pp.47-57. ⟨10.1016/j.margeo.2013.08.006⟩, Marine Geology, Elsevier, 2013, 346, pp.47-57. ⟨10.1016/j.margeo.2013.08.006⟩, Marine Geology (0025-3227) (Elsevier Science Bv), 2013-12, Vol. 346, P. 47-57, HAL Clermont Université, Hyper Article en Ligne, Hal-Diderot, Datacite, UnpayWall, ORCID, Microsoft Academic Graph, ArchiMer-Institutional Archive of Ifremer, Mémoires en Sciences de l'Information et de la Communication
- Publication Year :
- 2013
- Publisher :
- HAL CCSD, 2013.
-
Abstract
- International audience; Submarine canyon heads are key areas for understanding the triggering factors of gravity currents responsible for the transfer of detrital sediment to the deep basins. This contribution offers a detailed picture of canyon heads off La Réunion Island, with high-resolution multibeam bathymetry in the water depth range of 4-220 m. The present feeding of the Cilaos turbidite system, one of the largest modern volcaniclastic systems in the world, is deduced from morphological and sedimentological interpretations of newly acquired data. The study highlights small-scale sedimentary features indicating hydrodynamic and sedimentary processes. A direct connexion between the Saint-Etienne river mouth and submarine canyons is evidenced by the complete incision of the shelf and the presence of canyon heads connected to the modern deltaic bar. This direct connection, supplied by river torrential floods (cyclonic floods every two or three years), suggests the continuity of high-density fluvial flows to submarine gravity flows, forming hyperpycnal flows in the canyon. The initiation of secondary submarine gravity flows by storm waves (large austral waves and cyclonic waves) is also proposed for submarine canyons with large canyon heads developed in the surf zone from a sandy coastal bar. Bedforms in active canyon axis are considered as an indicator of the frequent activity of high-density turbidity currents. Moreover, a morphological record of last glacial and deglacial sea level variations is preserved, and particularly the Last Glacial Maximum sea level with the presence of small vertical cliffs, observed in this bathymetric data, which likely corresponds to a paleo-shoreline or paleo-reefs.
- Subjects :
- canyon head
Turbidity current
010504 meteorology & atmospheric sciences
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Fluvial
Submarine canyon
Surf zone
010502 geochemistry & geophysics
Oceanography
01 natural sciences
Geochemistry and Petrology
River mouth
Bathymetry
14. Life underwater
turbidity current
Sea level
0105 earth and related environmental sciences
Canyon
geography
geography.geographical_feature_category
Geology
coastal instability
submarine canyon
13. Climate action
hyperpycnal flow
Subjects
Details
- Language :
- English
- ISSN :
- 00253227
- Volume :
- 346
- Database :
- OpenAIRE
- Journal :
- Marine Geology
- Accession number :
- edsair.doi.dedup.....c50a463f47cd2b2d87224967ab28e7bf