Stratigraphic organisation of a composite macrotidal wedge: the Holocene sedimentary infilling of the Mont-Saint-Michel Bay (NW France)

A significant shift in the sedimentary infilling of Mont-Saint-Michel Bay occurred around 6500 years ago, marking a transition from rapid sea-level rise to a highstand phase. This change reshaped the bay's landscape into three distinct sub-environments: a mud-to-sand flat embayment, an estuarine channel-and-shoal system, and a wave-dominated sandy coast with dune barriers. The study, using vibrocores and high-resolution seismic data, reveals that the highstand phase (post-6500 yr B.P.) dominates the bay's infill, characterized by aggradational units in the back-barrier tidal lagoon and embayment, as well as a sand-dominated tidal channel-and-shoal belt. The interplay between sea-level rise, hydrodynamic forces, sediment supply, and climate changes, alongside the rocky substrate's hypsometry, collectively controls the bay's sedimentary architecture.

Tessier, B., Billeaud, I., & Lesueur, P. (2010). Stratigraphic organisation of a composite macrotidal wedge: the Holocene sedimentary infilling of the Mont-Saint-Michel Bay (NW France). Bulletin de La Société Géologique de France, 181(2), 99–113. https://doi.org/10.2113/gssgfbull.181.2.99