The Eemian stage in the Netherlands: history, character and new research

A historical outline of the Eemian research in the Netherlands is presented as an introduction to recent research in the type area. At the end of the 19th and during the first parr of the 20th century, Eemian sediments were r ecognized because of the presence of lusitanian and mediterranean mollusc s pecies. From 1930 onwards, pollen analysis made it possible to identify als o non-shell-bearing deposits and to equate them with the Eemian. At the sam e rime this technique proved a valuable tool for understanding the vegetati on development during this interglacial. Pollen zonation offered a unique p ossibility for the correlation of terrestrial sequences in North-West Europ e. The type area of the Eemian, near Amersfoort, was described by Harting in 1 874 and was comprehensively restudied by Zagwijn (1961). A pollen zonation was introduced as a standard for the Netherlands, allowing the correlation of pollen records from both marine and non-marine depositional environments . This enabled a more detailed temporal resolution, resulting in a better u nderstanding of the distribution of the various environments in the type ar ea. In the northern and central parts of the Netherlands, the identification of the marine sequence was, apart from the occurrence of the specific mollusc fauna, facilitated by the presence of a till of Saalian age underlying the Eemian deposits. The presence of deep glacial basins in these areas enable d the deposition and preservation of a complete Eemian record in a marine s etting. Sediment accumulation in the basins began immediately following deg laciation at the end of the Saalian. The Eemian type sections at Amersfoort are situated near the margin of one of these basins. Recent research of the Eemian focused on the integration of lithostratigrap hic evidence and information on the sedimentary environment as derived from diatoms, dinoflagellates, foraminifers, molluscs and pollen.