Processes that can disturb the chronostratigraphy of laminated sediments and pollen deposition

Abstract

The sediment trap technique was used to study the sedimentation processes in two parts of Lake Gościąz, central Poland, the deep of the main basin and the shallow bay area. From field and lab data was noted that seasonal and annual deposition of pollen grains on the lake bottom was disturbed in the main basin by an increase in water mass dynamics and by resuspension and focusing. Greater concordance between pollen sedimentation and the flowering periods of plants was found in the bay area, where sediment resuspension took place sporadically and with less intensity, compared to the main basin. Futhermore, it is suggested that resuspension of pollen can occur even if laminated sediments are formed, a process which therby diminishes the chronostratigraphic value of sediments and pollen analyses.