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

Abundant sedimentological and geochronological data gathered on European sandy coasts highlight major phases of increased high-energy sedimentation in the North Atlantic Ocean during the late Holocene. Owing to an inconsistent use of the terminology, it is often difficult to determine whether studies have described storm-built or wave-built deposits. Both deposits can be identified by overall similar coarse-grained sedimentary facies, but may provide contradictory paleoenvironmental interpretations. The aim of this study is to address this issue, by analysing a set of published 14C ages recovered from wave-built sediment bodies of the Pertuis Charentais (France). Integration of 14C data highlights seven coarse-grained sedimentation pulses (CSPs) that reflect a synchronous increase in wave-induced sediment supply occurring around 2650, 2420, 1240, 970, 800, 650 and 450 cal. yr B.P. CSPs can be matched with geochronological data published on other exposed sandy coasts of the western Europe. In first order, CSPs were preserved during phases of decreased storm activity and thus limited coastal erosion in the North Atlantic Ocean from 2700 to 2000 and from 1200 to 600 cal. yr B.P. In second order, CSPs occurred during positive NAO and/or negative EA/WR peaks, which are known from previous studies to induce higher waves and to enhance wave-induced sediment transport in the Pertuis Charentais. Chronological boundaries of CSPs could be used as a diagnostic tool to differentiate storm deposits indicative of sudden, episodic very high-energy sedimentation from wave deposits resulting from the sustained action of above-average westerly winds blowing across the North Atlantic Ocean.