Large sediment waves over the Gulf of Roses upper continental slope (NW Mediterranean)

Marta Ribó, Ruth Durán, Pere Puig, David Van Rooij, Jorge Guillén, Pere Masqué

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Large sediment waves have been observed over the Gulf of Roses (GoR) continental slope (NW Mediterranean), developed between ~200 and ~400 m water depth. Geometric parameters computed from the acquired swath bathymetry revealed mean wave lengths of ~2000 m, and maximum wave heights of ~60 m. Single-channel reflection seismic profiles provided information on the sediment wave internal structure and the Quaternary stratigraphic architecture of the GoR outer shelf and slope. Seven main seismic units could be identified, with continuous development of sediment waves over the outer continental shelf and upper slope, showing differences in wave height and length. The seismic units are differentiated by erosional surfaces that can be followed from the outer shelf down the slope, and which have been correlated with Pleistocene eustatic oscillations. Sediment cores were collected over the sediment wave crests and troughs, and grain size distribution and sediment accumulation rates were analysed. Results show a dominant fraction of fine sediments, allowing classifying the observed bedforms as mud waves. Calculated sediment accumulation rates ranged between 0.08 and 0.18 cm/y, with no clear sedimentation pattern (e.g. differential sediment deposition rates) observed between wave crests and troughs. Nevertheless, the presence of thick surface mixed layers and the increase of the sand fraction in the upper sections of the cores indicate that the surface sediments are affected by bottom trawling activities, since the area is highly impacted by this human activity. The sediment waves observed over the GoR slope are most likely to be formed by bottom currents generated by overflows of dense water originated in the Gulf of Lions shelf, which cascade downslope in an oblique angle with respect the main bathymetric contours. This study offers new insights on the role of dense shelf water cascading processes and associated off-shelf sediment transport reshaping the morphology of the open-slope regions.
LanguageEnglish
Pages84-96
Number of pages13
JournalMarine Geology
Volume399
Early online date15 Feb 2018
DOIs
Publication statusPublished - 1 May 2018

Fingerprint

sediment wave
continental slope
Sediments
sediment
wave height
accumulation rate
trough
swath bathymetry
wavelength
dense water
shelf sediment
bottom trawling
bottom current
bedform
seismic reflection
mixed layer
sediment core
sediment transport
continental shelf
surface layer

Keywords

  • Continental slope
  • Dense shelf water cascading (DSWC)
  • NW Mediterranean Sea
  • Sediment waves

Cite this

Ribó, M., Durán, R., Puig, P., Van Rooij, D., Guillén, J., & Masqué, P. (2018). Large sediment waves over the Gulf of Roses upper continental slope (NW Mediterranean). Marine Geology, 399, 84-96. https://doi.org/10.1016/j.margeo.2018.02.006
Ribó, Marta ; Durán, Ruth ; Puig, Pere ; Van Rooij, David ; Guillén, Jorge ; Masqué, Pere. / Large sediment waves over the Gulf of Roses upper continental slope (NW Mediterranean). In: Marine Geology. 2018 ; Vol. 399. pp. 84-96.
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abstract = "Large sediment waves have been observed over the Gulf of Roses (GoR) continental slope (NW Mediterranean), developed between ~200 and ~400 m water depth. Geometric parameters computed from the acquired swath bathymetry revealed mean wave lengths of ~2000 m, and maximum wave heights of ~60 m. Single-channel reflection seismic profiles provided information on the sediment wave internal structure and the Quaternary stratigraphic architecture of the GoR outer shelf and slope. Seven main seismic units could be identified, with continuous development of sediment waves over the outer continental shelf and upper slope, showing differences in wave height and length. The seismic units are differentiated by erosional surfaces that can be followed from the outer shelf down the slope, and which have been correlated with Pleistocene eustatic oscillations. Sediment cores were collected over the sediment wave crests and troughs, and grain size distribution and sediment accumulation rates were analysed. Results show a dominant fraction of fine sediments, allowing classifying the observed bedforms as mud waves. Calculated sediment accumulation rates ranged between 0.08 and 0.18 cm/y, with no clear sedimentation pattern (e.g. differential sediment deposition rates) observed between wave crests and troughs. Nevertheless, the presence of thick surface mixed layers and the increase of the sand fraction in the upper sections of the cores indicate that the surface sediments are affected by bottom trawling activities, since the area is highly impacted by this human activity. The sediment waves observed over the GoR slope are most likely to be formed by bottom currents generated by overflows of dense water originated in the Gulf of Lions shelf, which cascade downslope in an oblique angle with respect the main bathymetric contours. This study offers new insights on the role of dense shelf water cascading processes and associated off-shelf sediment transport reshaping the morphology of the open-slope regions.",
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Ribó, M, Durán, R, Puig, P, Van Rooij, D, Guillén, J & Masqué, P 2018, 'Large sediment waves over the Gulf of Roses upper continental slope (NW Mediterranean)', Marine Geology, vol. 399, pp. 84-96. https://doi.org/10.1016/j.margeo.2018.02.006

Large sediment waves over the Gulf of Roses upper continental slope (NW Mediterranean). / Ribó, Marta; Durán, Ruth ; Puig, Pere; Van Rooij, David; Guillén, Jorge; Masqué, Pere.

In: Marine Geology, Vol. 399, 01.05.2018, p. 84-96.

Research output: Contribution to journalArticleResearchpeer-review

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AU - Ribó, Marta

AU - Durán, Ruth

AU - Puig, Pere

AU - Van Rooij, David

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AU - Masqué, Pere

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