Holocene sedimentary infilling of a tide-dominated estuarine mouth. The example of the macrotidal Seine estuary (NW France)

Abstract

International audienceThe results of a seismo-stratigraphic study performed to study the Holocene sedimentary infilling at the mouth of the Seine River are presented. Combined data comprise very high resolution seismic reflection profiles, vibrocores, up to 4.5 m long, radiocarbon dating and old bathymetric charts. The infill is divided into two main stages: the transgressive systems tract, relative to the early Holocene high rate of sea-level rise, from 9000 to 7000 cal B.P., made of fine-grained, organic-rich, tidal flat to swamp deposits; the highstand systems tract, relative to the middle to late Holocene low rate of sea-level rise, from 7000 to 3000 cal B.P., characterized by the development of the high energy estuarine body above the main axis of the incised valley. Simultaneously, on the southern edge of the valley, a coastal barrier constructed above a bedrock plateau under the dominant action of waves. At 3000 cal B.P., probably in relation to a major climatic deterioration, the destruction of the barrier occurred and the tidal estuarine body expanded finally over the whole incised valley area. The rate of sea-level rise and the bedrock morphology appear to be the two main key-factors that control the sedimentary infilling architecture of this macrotidal, tide-dominated estuarine setting at the pluri-millenium Holocene time scale. Also, rapid climate changes determine part of the infill pattern, especially during the late Holocene sea-level highstand context

The Holocene transgression as recorded by incised-valley infilling in a rocky coast context with low sediment supply (southern Brittany, western France)

“…6500 B.P. [Tessier et al, 2010a, b]. Along with the extremely reduced volume of the HST, the late development of the MFS can be regarded as a characteristic of the sedimentary infilling of incised valleys located in a context of rocky coasts with low sedimentary supply.…”

Compound incised-valley characterization by high-resolution seismics in a wave-dominated setting: Example of the Aude and Orb rivers, Languedoc inner shelf, Gulf of Lion, France

“…Diffracting facies (Gas) -The masking effect of SF3 is referred to as "acoustic blanking" (Duarte et al 2007) and is characteristic of biogenic gas accumulation encountered into either deep or shallow water environments (Edgerton et al 1966;Stefanon 1985). In shallow waters, gas occurrence is common in fine and organic-rich muds accumulated in low-energy environments with high biogenic production such as protected embayments, estuary central basins and offshore prodelta systems (Aloisi and Monaco 1980;Gensous and Tesson 2003;Garcia-Garcia et al 2004;Tessier et al 2010;Labaune et al 2005).…”

Climate control on late Holocene high-energy sedimentation along coasts of the northeastern Atlantic Ocean

“…These discrete coarse layers are also recognised offshore, in the wave-influenced outer section of estuaries (Baltzer et al, 2014;Sorrel et al, 2009). Another dominant feature is the detection of discrete erosional discontinuities in estuaries (Billeaud et al, 2009;Tessier et al, 2010) and lagoons (Ferrer et al, 2010), indicative of prolonged phases of sediment remobilisation and/or erosion.…”