Stratigraphy of alluvial fills and phases of the Holocene floods in the lower Wisłok River valley, SE Poland

Abstract

Stratigraphy of alluvia and chronology of the Holocene flood events were studied on the basis of 50 radiocarbon dates as well as sedimentological and palynological analyses made on 20 depositional sequences of sediments in the lower section of the Wislok River valley. These sites evidence the occurrence within the 4–5 m and 6–7 m high levels of the floodplain of separate alluvial fills and palaeochannel systems, recording phases of increased Wislok activity and frequent floods dated at: the Allerod-Younger Dryas Phase, 9,900–9,600 BP, 8,500–8,000 BP, 6,600– 6,100 BP, 5,400–5,000 BP, 4,400–4,000 BP, 2,100–1,700 BP, as well as the 11–13th centuries AD and the middle of the 18th century AD. These periods are in accordance with the phases documented earlier within the Upper Vistula River drainage basin, particularly in the for-mountainous section of the Wisloka River valley, Vistula River valley downstream of Krakow , as well as in the Lower San River valley.