Data/hora: 07/06/2024 01:54:07

Provedor de dados: | 5
País: | France
Título: | Different types of sediment gravity flows detected in the Var submarine canyon (northwestern Mediterranean Sea)
Autores: | Khripounoff, Alexis; Crassous, Philippe; Lo Bue, N.; Dennielou, Bernard; Silva Jacinto, Ricardo.
Data: | 2012-11
Ano: | 2012
Resumo: | Current velocities and vertical sediment fluxes in the Var submarine canyon were assessed at three stations respectively at 800 m, 1200 m and 1800 m depth, using moorings deployed for 4 months during winter 2008-2009. During this period, we observed three major sediment gravity flows, all characterized by sudden increases in current velocity that lasted 2-5 h and by downward particle fluxes. Each gravity flow, described using a high frequency current meter and two Acoustic Doppler Current Profiler (75 and 300 kHz ADCP) showed distinctive features. The first event, triggered during a flood of the Var River, was determined to be a hyperpycnal current with a large vertical extent (&gt;100 m high) and relatively low velocity (40 cm s(-1)). The second event, observed after a Var River flood, was more energetic with a maximum horizontal current peak of 60 cm s(-1) with a low vertical extent (30 m high). This event was considered to be a turbidity landslide. The third was the result of a local canyon wall failure. It was characterized by a speed of &gt;85 cm s(-1). These peaks of current speed were associated with large clouds of material that transported sediment along the canyon and reached up to 200 g m(-2) d(-1) of sediment (&gt;1 g m(-2) d(-1) of organic carbon). Our measurements in the Var canyon show the important role of gravity flows transporting particulate matter to the deep-sea floor. These large inputs of sediment and organic carbon may have a significant impact on deep-sea carbon storage in the Mediterranean Sea. (C) 2012 Elsevier Ltd. All rights reserved.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/00113/22394/20343.pdf

DOI:10.1016/j.pocean.2012.09.001

Editor: | Pergamon-elsevier Science Ltd
Relação: | http://archimer.ifremer.fr/doc/00113/22394/
Formato: | application/pdf
Fonte: | Progress In Oceanography (0079-6611) (Pergamon-elsevier Science Ltd), 2012-11 , Vol. 106 , P. 138-153
Fonte: | 2012 Elsevier Ltd. All rights reserved.