Reconstruction of hydrological changes between 7000 and 3000 BP in the upper and middle Vistula River Basin, Poland

Abstract

Rhythmic fluctuations in the hydrological regime are demonstrated based on a review of records sensitive to relative climatic stability between 7000 and 3000 BP in the upper and middle parts of the Vistula River Basin, central Europe. In the fluvial deposits and landforms these variations are very clear; phases of higher flood frequency are dated 6600-6000, 5500-4750, 4500-4100 and 3250-3000 BP. These phases coincide very well with sparse information on landslides, data on high lake levels in the early Subboreal, phases of forest-ecosystem transformation and, finally, the reaction of human cultures to these changes. Their rhythmicity correlates well with records from the Alps and the Alpine foreland but poorly with those from Scandinavia. This may be explained by changes in the zonal pattern of air- mass circulation. Among the causes of the humid phases, it is the frequency of volcanic eruptions which should be taken into consideration.