Deeply incised rivers between Montfoort and Zevenhuizen

Abstract

In the area between Montfoort (province of Utrecht) and Zevenhuizen (province of South- Holland) in the Netherlands, four instances of deep depressions in the Weichselian terrace level were investigated. It was suspected that these depressions were the remnants of early Holocene (10.150 – 6000 BP) incised rivers in the area. Old and new corings were investigated in terms of lithology and a number of cores was analysed by loss-on-ignition and palaeobotany to gain insight in the geographical spread, way of forming and age of the depressions. On three locations it was determined that the present depressions represented residual channels of early Holocene incised riviers. The channels are mostly filled with clastics, probably because of the activity of younger aggrading rivers. On the research location of Haastrecht it was determined that the present depression represents a residual channel of Weichselian age, which was filled with organic deposits in the Early Holocene.