Sand bodies at the shelf edge in the Gulf of Lions (Western Mediterranean): Deglacial history and modern processes
|Author(s)||Bassetti Maria-Angela1, 2, Jouet Gwenael1, 2, Dufois Francois3, 4, Berne Serge1, Rabineau Marina2, 6, Taviani M5|
|Affiliation(s)||1 : IFREMER, GM, F-29280 Plouzane, France.
2 : IUEM, UMR 6538, F-29280 Plouzane, France.
3 : IFREMER, ECTO, F-29280 Plouzane, France.
4 : INFM, IRSN, F-83507 La Seyne Sur Mer, France.
5 : CNR, ISMAR, I-40126 Bologna, Italy.
|Source||Marine Geology (0025-3227) (Elsevier), 2006-12 , Vol. 234 , N. 1-4 , P. 93-109|
|WOS© Times Cited||59|
|Keyword(s)||Gulf of Lions, Sand transport, Deglacial transgression, Outer shelf, Sand ridges|
|Abstract||The outer continental shelf of the Gulf of Lions is covered by thick, mainly regressive, sand deposits. A combination of seismic, sedimentological and geochronological methods allows us to demonstrate that a veneer of transgressive sand bodies, few m to less than 1 m thick, reworks these deposits. They take the form of sand ridges and transverse dunes that formed at different periods. In fact, the low-gradient outer shelf of the Gulf of Lions displays a complete record of deglacial history, including not only transgressive deposits that formed during sea-level rise, but also bedfonns that still evolve under episodic high-energy events that occur under more highstand conditions. Core lithology, C-14 dates and regional sea-level curve suggest that the formation of the sand ridges was favoured during a period of deceleration of sea-level rise, such as during the Younger Dryas event. The dunes are part of a "mobile carpet" (here U160). The deposition of this marine sand veneer is possibly related to the interplay between different factors that trigger the turning on/off for bottom currents sand deposition/transport on the outer shelf. In fact, the sands appear to have been reworked intermittently due to high-energy conditions in shallow water depth (currents, wave regime and wind-driven circulation) as well as they form current ridges superimposed to the transgressive deposits in the westernmost part of the studied area (at the Bourcart Canyon's head).|