HR: 1340h
AN: OS23C-1329    [Abstracts]
TI: Depositional history of the post-glacial transgression on the outer continental shelf of the Gulf of Lions (western Mediterranean)
AU: * Bassetti, M A
EM: Maria.Angela.Bassetti@ifremer.fr
AF: DRO-GM IFREMER, BP 70, Plouzane, 29280 France
AU: Jouet, G
EM: Gwenael.Jouet@ifremer.fr
AF: DRO-GM IFREMER, BP 70, Plouzane, 29280 France
AU: Berne, S
EM: Serge.Berne@ifremer.fr
AF: DRO-GM IFREMER, BP 70, Plouzane, 29280 France
AU: Taviani, M
EM: marco.taviani@bo.ismar.cnr.it
AF: ISMAR-CNR, via Gobetti 101, Bologna, 40100 Italy
AU: Leroux, E
EM: Estelle.Leroux@ifremer.fr
AF: DRO-GM IFREMER, BP 70, Plouzane, 29280 France
AU: Perez-Belmonte, L
EM: lucia.perez-belmonte@univ-ubs.fr
AF: UBS, Campus Tohannic-CER "Yves Coppens" BP 573, Vannes, 56017 France
AB: Late Pleistocene sedimentation on the Gulf of Lions continental shelf was investigated using a combination of seismic, sedimentological and geochronological methods. According to the calibrated age data generated in the cores material, a correlation between the transgressive seismic units (and associate coastal features) and the post-glacial climatic/sea level changes was attempted. The formation of trangressive deposits was favoured during short-term cool episodes, such as Younger Dryas Event, as well as ancient sea-level positions can be assigned on the basis of the easily recognizable coastal features. The internal structure of the transgressive deposits and sedimentation processes are largely controlled by the nature of sea-level rise (deceleration or short-lived sea-level stillstands), sediment supply changes, and paleogeographic/paleoceanographic conditions related to post-glacial transgression. Sedimentological data (sedimentary facies and fossil content) and depositional ages determined on the 14C radiocarbon dating of well-preserved fossil shells allow us to establish a chronostratigraphic sequence that concerns the transgressive deposits of the Gulf of Lions. In particular, the combined use of available data permit: (1) to trace the ravinement surfaces, possibly related to mpwIA and mpwIB events, throughout the outer shelf; (2) to detect the nature of preserved sedimentary bodies that are mainly related to the deceleration of sea-level rise during the major post-glacial cold event (submerged dunes formed during Younger Dryas); (3) to describe the characteristics of the ravinement deposits and the degree of preservation of relict sediments on the shelf depositional environments. In fact, the post-Last Glacial Maximum transgressive phase occurs as complete record in the low-gradient outer shelf of the Gulf of Lions, but the deposits show a thickness that is considerably thinner with respect to the inner shelf area. They are seen as the distal part of the TST-HST margin deposits but they clearly document the effect of the sea level change on sedimentation pattern in wave-dominated shelf environment. Aloisi, J.C, Monaco, A., Thommeret, J., Thommeret Y. G‚ogr. Phys.Quatern., 32, 145-162, (1978). Rabineau, M., Berne, S., Ledrezen, E., Lericolais, G., Marsset, T., Rotunno, M. Mar.Petr.Geol., 15, 439-452, (1998).
DE: 3022 Marine sediments--processes and transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting