Wiek oraz przebieg przyrostu miąższości mad na tarasie zalewowym Wisły w rejonie Warszawy w świetle stanowisk archeologicznych

Abstract

AGE AND COURSE OF THICKNESS INCREASE OF MUDS ON THE VISTULA HOOD TERRACE IN THE REGION OF WARSAW, IN THE LIGHT OF ARCHEOLOGICAL SITES Summary The article deals with the preliminary results of the researches an age determination and on the course of thickness increase of muds on the Vistula flood terrace in the region or (Warsaw) proved by the dated archaeological finds. It results from the analyses of geological sections of muds that show preserved and interfingered culture traces accumulated in a mould bed during a period to the late mediaeval period, that two different mud series have boon accumulated on the Vistula flood terrace. Accumulation of the muds of the lower series (older series) took probably place during the eubboreal period. Then, during a period of over 2000 years, maybe also during a longer period, the Vistula river flood waters did not accumulate muds on the terrace, thus did not invade cyclically the terrace considered. Accumulation of the muds of the upper series (younger series) began only at the late mediaeval time (XV century) and persisted up to the beginnings of the XX century, i.e. to the time of construction of a river embankment. On the average, the mean annual increase of muds of the upper series amounts to about 0.5 mm. The fossil mould bed with certain traces of human settlements and cemeteries, seen in the rounds of the flood terrace, prove that the Vistula river bed was, in the region here considered, throughout about 2500 years, fairly stable and did not undergo any greater lateral displacements.