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

The 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 similar to 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 cycles.