Title of article :
Recent sediment transport and deposition in the Nazaré Canyon, Portuguese continental margin
Author/Authors :
de Stigter، نويسنده , , Henko C. and Boer، نويسنده , , Wim and de Jesus Mendes، نويسنده , , Pedro A. de Jesus Mendes، نويسنده , , Carlos César and Thomsen، نويسنده , , Laurenz and van den Bergh، نويسنده , , Gert D. and van Weering، نويسنده , , Tjeerd C.E.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Pages :
21
From page :
144
To page :
164
Abstract :
Processes, pathways and fluxes of sediment transport and deposition in the Nazaré submarine canyon, Portuguese continental margin, were investigated by water column profiling of suspended particulate matter, recording of near-bottom currents and suspended particulate matter fluxes with benthic landers, and by analysis of surface sediment cores. The results show that fine-grained suspended sediment from the adjacent shelf is captured in the upper canyon and actively transported through the canyon to the abyssal plain under influence of tidal currents and intermittent sediment gravity flows. Tidal currents are actively resuspending and transporting sediment in the upper to middle canyon, as reflected by high concentration of suspended particles in bottom waters, high horizontal and vertical sediment fluxes in the bottom water layer and high sediment accumulation rate on the seabed. Diminishing strength of tidal currents leads to focussed sediment deposition in the middle canyon. Further transport of sediments toward the lower canyon takes place predominantly by sediment gravity flows occurring on yearly or longer timescale. Turbidity currents strong enough to transport sand-sized material to the lower canyon occur only on centennial or longer timescales.
Keywords :
Submarine canyon , suspended sediment transport , internal tide , Sediment gravity flow
Journal title :
Marine Geology
Serial Year :
2007
Journal title :
Marine Geology
Record number :
2261372
Link To Document :
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