RIVER RESPONSE TO THE HOLOCENE CLIMATIC FLUCTUATIONS: A CASE STUDY FROM ZELVIANKA RIVER VALLEY (BELORUSSIA)

Abstract

Kalicki T. (et.al.), River response to the Holocene climatic fluctuations: a case study from Zelvianka river valley (Belorussia).
(IT ISSN 0394-3356, 2004).
A multidisciplinary research aimed at depicting the evolution of Zelvianka river valley (NW Belorussia) during the Holocene has been
carried out. The valley incision started at the local ice-sheet terminus in the Young Pleniglacial following the Pomerian stage of the last
glaciation (some 16÷15 ka BP) and, as marked by important changes of the river regime, was virtually over at c. 13.8 ka BP (Middle
Lithuanian stage of deglaciation). Detailed geomorphologic survey coupled with stratigraphic analysis, 14C dating and pollen spectra
provided sound evidence that the complex structure of the valley bottom resulted from the lateral migration of the river which in turn
depended upon large-scale climatic changes. Besides of critically reviewing the literature data new, 14C dated pollen chronostratigraphies, fairly consistent with the up to date regional palynologic framework were obtained. Actually it has been found that the most important channel and sedimentation changes cluster at the AL/YD transition, c. 9300 BP, BO/AT transition, middle Atlantic, c. 4200 BP, c. 3250-3000 BP, Roman time (2100 BP) and 1000-900 BP, thus matching the timing of humid and cool climatic phases recorded by the enhanced activity of Belorussian and central European rivers. Though the first prehistoric settlements over the study area date back to Late Neolithic, Zelvianka valley was virtually unaffected by the human impact, except from some low intensity, local aeolian processes which developed in the Subboreal and Subatlantic on the deforested spots.