Lithology, stratigraphy, and palynology of Holocene deposits in the Drentsche Aa valley system

Abstract

The brook deposits of the Singraven Formation in the Aa valley are described and dated by respectively six cross sections and seven pollen diagrams. Three lithozones are discriminated: a sand bed, a detritic gyttja bed and a peat bed. The influence of the Holocene sea level rise on the deposition of the detritic gyttja bed in the downstream part of the valley is discussed. From the palynological data it is concluded that the Singraven Formation in the valley is confined to the Holocene. Two fluvial erosion phases causing headward erosion are distinguished: a Late Dryas phase, anticipating the deposition of the Singraven Formation, and a Late Boreal/Early Atlantic phase. Possible causes of these erosion phases are mentioned.