Contribution to the stratigraphy of the Weichsel Pleniglacial in the Belgian Coversand area

Abstract

Earlier stratigraphical studies of the upper Quaternary in N.W. Belgium have been supplemented with some recently obtained dates, which allowed to make a new approach to construct a more detailed stratigraphical table of the Weichsel Pleniglacial in this region. Between a series of "laminated sands and silts" (undermost part) and a series of "coversands', (uppermost part) an important peat bed was found (Assebroek peat). The pollen spectrum indicates relative warm conditions. A 14 C-date of 30,700 BP was obtained and therefore the peat is correlated with the Arcy-Kesselt interstadial. The overlying "coversands" are characterized by three levels of ice wedges and frost cracks and by one pebble string. The formation of the lowermost level of large deep ice wedges is dated between 26,220 BP and 24,760 BP. It is shown that the severest climatic conditions during the Weichselian started very soon after the Arcy-Kesselt interstadial.