Recolonization of a Middle Eocene volcanic site: quantitative palynology of the initial phase of the maar lake of Messel (Germany)

The research well “Messel 2001” penetrated the sediments of the Middle Eocene maar lake at Messel (near Darmstadt, Hesse, Germany) completely. The core includes 140 m of lacustrine oil-shale overlying 90 m of clastic lake sediments which are assigned to the Middle and Lower Messel Formation, respectively. Numerical techniques like TWINSPAN and correspondence analysis have been applied to a high-resolution palynological study. The Lower Messel Formation is equivalent to the Initial Lake Phase and shows a clear succession of pollen and spore associations representing a succession of plant communities colonizing and invading the area which was previously devastated by the eruption(s). On the basis of the TWINSPAN, an Early and a Late Initial Lake Phase may be distinguished. But, throughout the Initial Lake Phase, the regional climax vegetation did not change substantially and had re-occupied the area finally at a time roughly representing the boundary between the Lower and the Middle Messel Formation.