Late Quaternary climate-ocean changes in western North Africa: offshore geochemical evidence

Understanding the North African response to natural climatic variability has become an important research focus in recent years, especially considering the uncertain influence of anthropogenic warming to present and future climate changes. Historic climatic perturbations are associated with changes in Atlantic circulation, which in turn have been linked to water resource and land degradation issues in North Africa. In this paper, Late Quaternary climate-ocean changes affecting western North Africa are investigated to provide a temporal contribution to the debate. Major and trace element palaeoenvironmental proxies recorded in a radiocarbon dated sediment core collected under an upwelling cell, offshore Cap Blanc (Mauritania), are analysed. Element groups representing terrigenous (Saharan dust) and biogenic (marine plankton) input, and ocean-bottom redox conditions, indicate that the region is sensitive to previously documented North Atlantic climate-ocean perturbations, such as Bond Cycles, Heinrich and Dansgaard-Oeschger events. Additionally, the African Humid Period is recognized and related to an intensification of the African monsoon system that enhanced North East Trade Wind driven upwelling. It appears from this study that North Atlantic sea-surface temperature strongly influences North African precipitation throughout the Late Quaternary, with Atlantic sea-surface warming associated with enhanced North African aridity.