Oceanic and climatic variability in the eastern tropical North Atlantic and over western Sahel during the last deglaciation and the Holocene

Abstract

For the last decades, climatologists and paleoecologists have focused their attention on the semi-arid Sahel region, one of the most sensitive areas on the planet to even small climatic shifts. Studies of West African paleohydrology reconstructed from continental records of lake-level fluctuations as well as from marine cores recovered off west tropical Africa have revealed alternating arid and humid conditions. These hydrological changes are thought to be associated with weakening and strengthening of the African monsoon circulation occurring on short and long - time scales. They are forced by shifts in the average latitudinal position of the Intertropical Convergence Zone (ITCZ) and its related tropical rainbelt in association with changes in high-latitude climate.The present study is based on the high-resolution palynological analysis of marine sediment cores recovered off the Senegal River mouth and provides a detailed reconstruction of the hydrological variability of western Sahel during the last deglaciation and the late Holocene and the past oceanic circulation variability in the eastern tropical Atlantic with respect to abrupt climate changes