Eemian - Definition of The Eemian

Definition of The Eemian

The Eemian Stage was first recognized from boreholes in the area of the city of Amersfoort, Netherlands by Harting (1875). He named the beds "Système Eémien", after the river Eem on which Amersfoort is located. Harting noticed the marine molluscan assemblages to be very different from the modern fauna of the North Sea. Many species from the Eemian layers nowadays show a much more southern distribution, ranging from South of the Strait of Dover to Portugal (Lusitanian faunal province) and even into the Mediterranean (Mediterranean faunal province). More information on the molluscan assemblages is given by Lorié (1887), and Spaink (1958). Since their discovery, Eemian beds in the Netherlands have mainly been recognized by their marine molluscan content combined with their stratigraphical position and other palaeontology. The marine beds there are often underlain by tills that are considered to date from the Saalian, and overlain by local fresh water or wind-blown deposits from the Weichselian. In contrast to e.g. the deposits in Denmark, the Eemian deposits in North America have never been found overlain by tills, nor in ice-pushed positions.

Van Voorthuysen (1958) described the foraminifera from the type site, whereas Zagwijn (1961) published the palynology, providing a subdivision of this stage into pollen stages. At the end of the 20th century, the type site was re-investigated using old and new data in a multi-disciplinary approach (Cleveringa et al., 2000). At the same time a parastratotype was selected in the Amsterdam glacial basin in the Amsterdam-Terminal borehole and was the subject of a multidisciplinary investigation (Van Leeuwen, et al., 2000). These authors also published a U/Th age for late Eemian deposits from this borehole of 118,200 ± 6,300 years ago. A historical review of Dutch Eemian research is provided by Bosch, Cleveringa and Meijer, 2000.