Marine Isotope Substage 5e and the Eemian Interglacial

The subdivision of Marine Isotope Stage 5 (MIS5) into five substages is robustly applicable to benthic oxygen isotope records from almost all areas of the ocean. The association of the Eemian Interglacial (in the sense that this concept is utilized by palynologists) with MIS 5e is widely agreed on the basis of a diversity of evidence. Here we present the first direct evidence regarding the relationships between the boundaries of these two stratigraphic entities. The base of the Eemian as recognized here is significantly younger than the base of MIS 5, and indeed falls within the isotopic “plateau” of MIS 5e during which global sea-level is thought to have been a few meters higher than at present. The termination of the Eemian Interglacial in Portugal as recognized in the palynological record in this core off southern Portugal is well within MIS 5d.