Isabel Mendes and Óscar Ferreira from CIMA,
in collaboration with researchers from IACT/CSIC, Coastal Carolina University, GEOMAR and IGME, just published an article in Palaeogeography, Palaeoclimatology, Palaeoecology.
The article investigates the temporal variability of flooding events of the Guadiana River during the middle to late Holocene, in the drowned paleo-valley of the Guadiana River, on the adjacent northern Gulf of Cadiz shelf. Two major depositional environments were distinguished, driven by the variable frequency of fluvial flooding events due to regional climate variability. Low terrigenous sediment input occurred under dry conditions in the middle to late Holocene (ca. 5800–1250 cal yr BP). Flood frequency and terrigenous sediment supply increased during the last ca. 1250 cal yr BP. During the last ca. 500 years the sediment supply was influenced by the North Atlantic Oscillation, with high terrigenous supply during negative NAO conditions. Our results corroborate an N-S gradient along the Atlantic Iberia during middle and late Holocene, with more humid conditions in the northwestern and drier conditions towards the southeast. The gradient weakened over the past ca. 500 years, with increased rainfalls and flood events during the Little Ice Age.