THE WATTEN BORING - AN EARLY WEICHSELIAN AND HOLOCENE CLIMATIC AND PALEOECOLOGICAL RECORD FROM THE FRENCH NORTH-SEA COASTAL-PLAIN

A deep boring (30 m), carried out at Watten (Nord, France) in 1990, ha s provided an opportunity to undertake palaeoecological studies based on stratigraphy, sedimentology, palynology, malacology and C-14 dating s on Early Weichselian and Holocene deposits. The location of the site in the inner zone of the coastal plain, extending in the Aa valley fr om the southernmost shores of the North Sea upstream to Watten, allows the comparison between interstadials recorded in a pure fluvial envir onment and the overlying Holocene sediments, in which alternation of m arshy, fluvial and marine deposits are observed. The Early Weichselian sequence can be correlated with the Brorup and Odderade interstadials described in northwestern Europe, and belongs within the same palaeog eographical area. At that time the conditions were already continental at Watten. However, the last (Holocene) interglacial has bean charact erized, at least since the Boreal chronozone. by an oceanic climate an d a progressive invasion of the sea, sometimes interrupted by stillsta nds and withdrawals.