History of the sedimentary regimes of the Aquitaine margin (Bay of Biscay, France) at the outlet of its main tributaries during the last millennium: a mirror of the North Atlantic and European climates

The present work is based on the analysis of two hemipelagic sequences collected off the two main fluvial tributaries that enter the southern Bay of Biscay along the Aquitaine margin: the Gironde estuary, for core JB7-ST3c retrieved from the West-Gironde mud patch; and the Adour river, for core MD03–2693 retrieved from the Capbreton canyon meanders. Their positioning, at the northern and southern edges of the Aquitaine shelf, not only allows us to obtain a synoptic view of the southern Bay of Biscay past oceanography, but, over the last thousand years covered by these archives, also provides access to key contextual elements related to local as well as global hydroclimatic forcings. This article focuses on the interpretation of the sedimentological signal based on key X-ray fluorescence (XRF) elemental profiles obtained along the cores, within the framework of coherent age models newly built for the two sequences. The consistency of the two records allows us to robustly relate the evolution of the XRF profiles to the hydroclimatic regime of the Bay of Biscay, and to compile and discuss a chronicle of the environmental events that have marked the sites. This is achieved through a regional scale analysis, encompassing synchronous occurrences on the proximate continent, complemented by a broader synoptic perspective within the context of the well-documented European and North Atlantic historical frames. This chronicle is pivotal in comprehending the correlation between continental and oceanic regimes along the Euro-Atlantic margin, in addition to their links to the climatic processes that govern the Northern Hemisphere region. Our results clearly discriminate specific climatic trends, highlighting the Medieval Warm Period, the Little Ice Age and the Current Warm Period as contrasted intervals. The climatic patterns identified during these specific phases are discussed in the light of recent advances in our knowledge of their modes of variability, and raise the question of teleconnections between the North Atlantic Oscillation, Atlantic sea-surface conditions and dynamics, together with atmospheric ones and especially storminess over Europe. • River outlets in SW France are traps of past European hydroclimatic regimes. • Bay of Biscay archives integrate the recent history of climatic and hydrological events. • Neritic marine sediments reflect phenological records of the proximal continent. • Marine archives of past centuries reveal local and global climate dynamics.