25. Climate variability of the last five isotopic interglacials: Direct land-sea-ice correlation from the multiproxy analysis of North-Western Iberian margin deep-sea cores

Abstract

The last five isotopic interglacials (marine isotope stages 11, 9, 7, 5 and 1) were investigated in Iberian margin deep-sea cores, using terrestrial (pollen) and marine (planktic foraminifera assemblages, benthic and planktic oxygen isotopes) climatic indicators. This work shows that the climatic variability detected on the continent is contemporaneously recorded in the ocean, but temperature changes are not in phase with ice volume variations. The comparison of the different marine isotope stages highlights a common pattern within these stages. They are characterized by three major climatic cycles, related to orbital cyclicity, on which suborbital climatic fluctuations are superimposed. Particularly, suborbital events interrupt the deglacial warming associated with Terminations IV to I and the second major warm period of each isotopic interglacial as well as the transitions towards glacial marine isotope stages. MIS 7 displays a short first warm period (8kyr) followed by a striking cold and dry period succeeded by a new strong warmth. In contrast, MIS 11 presents the longest period (31kyr) of the last 450000 years. © 2007 Elsevier B.V. All rights reserved.