FN Archimer Export Format
PT J
TI Numerical modelling of a Macrotidal Bay over the last 9,000 years: An interdisciplinary methodology to understand the influence of sea-level variations on tidal currents in the Bay of Brest
BT 
AF OLIVIER, Matthieu Guillaume
   Leroux, Estelle
   Rabineau, Marina
   Le Hir, Pierre
   Granjeon, Didier
   Chataigner, Teddy
   Beudin, Alexis
   Muller, Heloise
AS 1:1,3,4;2:1;3:4;4:2;5:3;6:5;7:6;8:2;
FF 1:PDG-REM-GM-LGS;2:PDG-REM-GM-LGS;3:;4:PDG-ODE-DYNECO-DHYSED;5:;6:;7:;8:PDG-ODE-DYNECO-DHYSED;
C1 IFREMER – LGS laboratory – Pointe du Diable, 29280, Plouzané, France
   IFREMER – DYNECO/DHYSED laboratory – Pointe du Diable, 29280, Plouzané, France
   IFP Énergies nouvelles – 1 et 4, avenue de Bois-Préau, 92500, Rueil-Malmaison, France
   Univ Brest, CNRS, Univ. Bretagne-Sud, Laboratoire Géosciences Océan (LGO), UMR6538, IUEM, rue Dumont d’Urville, F-29280, Plouzané, France
   ENPC, Hydraulics Laboratory, Saint-Venant, 6 quai Watier, 78400, Chatou, France
   BW-CGC, 53 rue du commandant Groix, 29200, Brest, France
C2 IFREMER, FRANCE
   IFREMER, FRANCE
   IFP ENERGIES NOUVELLES, FRANCE
   UBO, FRANCE
   ENPC, FRANCE
   BW-CGC, FRANCE
SI BREST
SE PDG-REM-GM-LGS
   PDG-ODE-DYNECO-DHYSED
UM LGO
IN WOS Ifremer UPR
   copubli-france
   copubli-univ-france
IF 2.629
TC 2
UR https://archimer.ifremer.fr/doc/00732/84402/89432.pdf
   https://archimer.ifremer.fr/doc/00732/84402/89433.docx
LA English
DT Article
DE ;Hydrodynamic modelling;Tidal currents;Paleoenvironmental reconstruction;Holocene sedimentation;Erosion and deposition potential indexes
AB Estuaries play a major role in the transfer of sediments from the continents to the shelves and deep ocean basins. Their position at the interface between land and sea promotes them as a key area for the understanding of ocean sediment supply, but yet long-term evolution remains poorly understood. The main reasons of the lack of knowledge about estuaries filling are the lack of hydrodynamic data in the past and the temporal application of numerical models. Oceanographers and geologists have developed numerical models to simulate currents and sedimentation. On one hand, hydro-sediment models allow a good physical representation of estuarine hydrodynamic processes and their impact on sedimentation, but only over time-scale spanning years to decades. On the other hand, stratigraphic diffusive models aim to study the impact of various geological processes on sedimentary basins over millions of years, but they are unable to describe in detail the tidal hydrodynamic processes that govern estuaries. In response to this timescale issue, this study presents a first step attempt to explore the evolution of tidal current distribution in relation with Holocene eustatic variations and seafloor evolution. Here we focus on a macro-tidal estuary, the bay of Brest, where tidal processes dominate, as the estuary is naturally protected from ocean swells. This paper aims to set up a methodology to simulate the (past) tidal currents over a long time period and correlate them with sedimentary data. Major changes in deposit dynamics are first identified from cores and seismic data, and the corresponding paleo-topographies and paleo-sea-levels are rebuilt. A process-based hydrodynamic model (MARS3D) is then used to test the impacts of these paleo-bathymetries on hydrodynamics over a 1-year time span. Four scenarii have been considered, representing four key stages of the Holocene transgression in the Bay of Brest. The simulated barotropic currents distributions were analysed and bottom currents impact on the seafloor compared with sedimentary records to understand past hydrodynamic context and associated sediment spatial distribution over geological time scale. Hydrodynamic simulations and sediments records are linked, in order to propose a reconstruction of the tidal influence on sediments over the last 9000 years. The results show changes of the tidal patterns related to the paleoenvironmental evolution (bathymetry and sea-level variations). Even if a hydro-sediment model would be needed to make a direct correlation between simulated currents and sediment records, this successful application in the Bay of Brest shows that discontinuous modelling can help to understand tidal current evolution and their impact on sediment distribution over long periods. 
PY 2021
PD DEC
SO Continental Shelf Research
SN 0278-4343
PU Elsevier BV
VL 231
UT 000717475400002
DI 10.1016/j.csr.2021.104595
ID 84402
ER

EF