5 research outputs found
Depositional controls on a hypertidal barrierâspit system architecture and evolution, Pointe du Banc spit, northâwestern France
(IF 3.24 [2018]; Q1)International audiencePhysical stratigraphy, architecture and evolution of barrier systems in hypertidal environments (tidal range above 6 m) are understudied, and depositional controls are poorly understood compared with waveâdominated barrier systems and barrier spits in microtidal, mesotidal and macrotidal settings. Based on vibracores, groundâpenetrating radar, radiocarbon and optically stimulated luminescence age data, the formation and evolution of the hypertidal barrier system of Pointe du Banc, northâwestern France has been reconstructed. The study shows that the barrier spit has a complex composite sedimentary architecture consisting of waveâdominated and tideâdominated sedimentary bodies. A morphoâsedimentary model is presented that demonstrates how barrierâspit progradation resulting from littoral drift was the main manner of spit elongation, whereas sediment convergence caused by landward migration of swash bars and seaward migration of tidal dunes caused the spit terminus to grow in height and width. These results suggest that longâterm accretion rates varied considerably in response to changes in sediment supply. Variations in storminess together with the largeâscale topography of the coast controlled the sediment supply and thus the evolution of the barrier system during latest Holocene. Despite architectural complexity, hypertidal barrier systems preserve records of past climate changes