Late Middle Pleistocene palynostratigraphy and landscape evolution in Western and Central Europe: Will the real Holsteinian Please Stand Up?

The chronostratigraphic position of the Holsteinian interglacial is a long-standing debate. Although few doubt the typical vegetation dynamics reflected in pollen diagrams, some researchers still disagree about the age: Marine Isotope Stage (MIS) 11 or MIS 9. At the same time, this disagreement hinders the construction of a solid late Middle Pleistocene (LMP) palynostratigraphic framework for Western and Central Europe. The presented solution focuses simultaneously on the chronostratigraphic position of the Holsteinian and the development of a palynostratigraphic framework by combining the palynology with the stratigraphic context of organic LMP deposits. The authors demonstrate the differences in geomorphological position and vegetation dynamics between the MIS 11 Holsteinian on the one hand and MIS 9 sequences on the other by visually comparing pollen diagrams and looking for MIS 9 and MIS 7 correlations in Western and Central Europe. Some pollen profiles previously interpreted as Cromerian reflect MIS 9 palynology as described in this paper. The revised palynostratigraphic framework results in a new landscape evolution model, a compromise between the law of superposition and river terrace models, that explains the stratigraphic context of the different LMP interglacial complexes, i.e. MIS 11, 9 and 7: a phase of pronounced fluvial incision during MIS 10 was followed by net accumulation during MIS 9–8-7 in Western and Central Europe.