Sabiia Seb
        Busca avançada

Botão Atualizar

Botão Atualizar

Registro completo
Provedor de dados:  ArchiMer
País:  France
Título:  Direct sediment transfer from land to deep-sea: Insights into shallow multibeam bathymetry at La Réunion Island
Autores:  Babonneau, Nathalie
Delacourt, Christophe
Cancouet, R.
Sisavath, Emmanuelle
Bachelery, Patrick
Mazuel, Aude
Jorry, Stephan
Deschamps, Anne
Ammann, Jerome
Villeneuve, N.
Data:  2013-12
Ano:  2013
Palavras-chave:  Submarine canyon
Canyon head
Turbidity current
Hyperpycnal flow
Coastal instability
Resumo:  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.
Tipo:  Text
Idioma:  Inglês

Editor:  Elsevier Science Bv
Formato:  application/pdf
Fonte:  Marine Geology (0025-3227) (Elsevier Science Bv), 2013-12 , Vol. 346 , P. 47-57
Direitos:  2013 Elsevier B.V. All rights reserved.

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC:

Valid HTML 4.01 Transitional