Impacts of late Holocene rapid climate changes as recorded in a macrotidal coastal setting (Mont-Saint-Michel Bay, France)

Abstract

International audienceThe impacts of rapid climate changes during the Holocene are well documented in deep oceanic and lacustrine sediments. Until now, no studies have shown the effects of rapid climate change on tidal successions in coastal wedges formed during the late Holocene transgression. Cores and very high resolution seismic data collected in Mont-Saint-Michel Bay, France, a macrotidal setting, demonstrate that rapid climate changes, with ~1500 year periodicity, are recorded in the sedimentary successions that constitute the late Holocene infill of the bay. The sedimentary expressions of rapid climate changes vary according to the different subenvironments within Mont-Saint-Michel Bay; cycles, a few meters thick, can be correlated throughout the bay, and radiocarbon dating suggests that they have a millennial time scale. The various changes reflect an increase in wave dynamics in association with Bond cold events, possibly in conjunction with long-term (1800 year periodicity) tidal cycle

Tidal and fluvial controls on the morphological evolution of a lobate estuarine tidal bar: The Plassac Tidal Bar in the Gironde Estuary (France)

“…25-and 50-year periodicities found in the Gironde fluvial discharge and the tidal bar dimensions suggest a climate control on the tidal bar development. The climate variability control on the development of other examples of sandbodies was also evidenced in wave-influenced or wave-dominated environments Bertin et al, 2008;Billeaud et al, 2009) showing that climate changes should be considered as an important controlling factor in sandbody development since it directly governs fluvial discharge, wave parameters and related sediment supply.…”

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.…”

“…In marine settings, the sedimentary expression of HSPs is more diverse. A dominant feature is the presence of discrete, millimetre to centimetre thick shelly sand to gravel layers embedded in back-barrier lagoonal successions (Degeai et al, 2015;Dezileau et al, 2011;Sabatier et al, 2008) or in marsh fine-grained sediments (Billeaud et al, 2009), interpreted as the imprint of barrier destruction and sand over wash . These discrete coarse layers are also recognised offshore, in the wave-influenced outer section of estuaries (Baltzer et al, 2014;Sorrel et al, 2009).…”

The Joint History of Tróia Peninsula and Sado Ebb-Delta

“…Storm winds in this region approach from the west and southwest, explaining the occurrence of very large blowouts around this age. Shoreline instability and inland aeolian sediment transference were also documented in other regions along the coasts of Portugal , France (Billeaud et al 2009;Sabatier et al 2012), England (Spencer et al 1998) or Denmark (Clemmensen et al 2009) and have been related to the onset of storminess conditions in the North Atlantic and the southward displacement of the westerlies (Sorrel et al 2012).…”