Holocene estuary development in the Algarve Region (Southern Portugal) – A reconstruction of sedimentological and ecological evolution

This paper presents a reconstruction of the former coastal estuaries of the Quarteira and Carcavai estuaries in southern Portugal based on sedimentological, geochemical and palynological analyses of Holocene sediment cores. The results show that each estuary developed differently, depending on the morphology of the palaeovalley, environmental conditions and especially the influence of the sea and the formation of barrier systems. Both estuaries were flooded between 7000 and 5500 cal BP by sea level rise and were almost completely filled by sediment by the beginning of the Roman occupation (226 BC/2176 cal BP). A clear change in sedimentological processes is evident in both estuaries between 5500 and 3000 cal BP and is interpreted as an erosion phase or evidence of high-energy events such as storms or tsunamis.