Late Neogene to Early Quaternary climate evolution in southwestern Europe from a continental perspective

Paleoclimate reconstructions are mostly based on continuous oceanic records, but continental records, controlled by global and regional conditions, are paramount in identifying long-and short-term climatic variability between regions and investigating forcing mechanisms. Here we present a high-resolution lacustrine log from a western Mediterranean intramountain basin; it is based on calcite oxygen isotope composition (delta O-18(c)) and records detailed paleoclimatic information from the Late Miocene to the Early Pleistocene (9.8-1.8 Ma). Evidence is found for orbital forcing in the regional paleoclimate, with minimum and maximum eccentricity related to drier and wetter conditions respectively. Superimposed onto this variability, the long-term trend reflects the influence of global paleogeographic and climate change. Variations inferred in precipitation-evaporation (P-E) are related to SST in the North Atlantic, which evidences a connection between marine dynamics and continental climate in areas far from the coast in southwestern Europe and a relation between dry periods and high SST inland. It is proposed that the regional climate was impacted by the effect of the closure of the Central Atlantic Seaway and changes in the Atlantic Meridional Overturning Circulation (AMOC). Warmer/drier conditions were related to a more permanent, stable, high-pressure centre over the mid-Atlantic in a situation of strengthened AMOC, which would have blocked westerly winds, increasing aridity in southwestern Europe. The inferred warm/dry connection differs from other western Mediterranean records, supporting previous interpretations of a regional climate gradient in western Europe. As occurs at present, isolation from the influence of the humidity of the Mediterranean Sea during warm periods as a result of' to the local orography could well have been the cause of regional differences.