Pluri-millenial to pluri-annual evolution of the sediment wedge at the River Seine mouth. Natural and anthropogenic controls.

• Main Author: Delsinne, N.
• Other Authors: Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Université de Caen, Tessier Bernadette([e-mail])
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2005
• Subjects: The river Seine mouth; macrotidal environment; estuarine infilling; coastal sedimentary prism; bathymetric charts; seismic VHR; sedimentary cores; hydro-meteorological time series; climatic factors; man-made modifications; Embouchure de la Seine; environnement macrotidal; comblement estuarien; Holocène; prisme littoral; cartes bathymétriques; sismique THR; carottes sédimentaires; chroniques hydro-météorologiques; facteurs climatiques; aménagements; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy; North Atlantic; North Atlantic oscillation
• Online Access: https://theses.hal.science/tel-00011470; https://theses.hal.science/tel-00011470/document; https://theses.hal.science/tel-00011470/file/theseDELSINNE2005.pdf

A sediment wedge, about 20 m thick, has emplaced at the mouth of the River Seine during the Holocene transgression. Two main methodological approaches have been developed to determine the controlling factors of its construction and morphosedimentary evolution: (1) very high resolution seismic investigation coupled with vibro-coring for studing the pluri-millenial evolution; (2) historic bathymetric chart comparison to analyse the centennial to pluri-annual evolution during the last two centuries. The long term (Holocene) evolution is controlled on one hand by the rate of sea level rise, on the other hand by the position of the main fluvial incision. The tidal inlet system remains active all along the construction above the incision, whereas the adjacent areas, particularly in the South, have filled rapidly. During the last two centuries, the infill can be divided into 3 main stages: from 1834 to 1875, the mouth is a wide migrating channelized system; from 1875 to 1960: supratidal areas develop and lateral infill occurs; from 1960 to now-days: the infill is mainly up-to downstream and marked by the development and rapid seaward progression of two tidal longitudinal bars. The impact of natural factors on this recent evolution is hard to identify as management works during this period are major; they are assumed to be the controlling agents. However high frequency climatic cycles such as the NAO (North Atlantic Oscillation) seem to play a significant role in the morphodynamic behaviour of the tidal mouth during the most recent period, as since the 1980's no more major managements have been performed. A l'embouchure de l'estuaire de la Seine, un prisme sédimentaire d'une vingtaine de mètres d'épaisseur s'est mis en place au cours de la transgression holocène. L'étude des facteurs de contrôle de sa construction et de son évolution morphosédimentaire a été menée selon deux approches : (1) à partir de données sismiques et de carottage pour étudier l'évolution à long terme (pluri?millénaire) (2) à partir de données ...