Abstrakt: | Lithological analyses and radiocarbon dating were used to elucidate the patterns and controls
of Late Quaternary valley floor development of the Kłodnica River, the Upper Odra Basin. The
research results were discussed with data obtained from valleys of rivers draining piedmont basins
and highlands of southern Poland. In consequence, five stages of morpho-sedimentary evolution of
the Kłodnica valley were distinguished. In the Late Vistulian a large-scale deposition of channel alluvium
took place in the conditions of high river discharges. This sedimentary style probably still existed
in the Early Pre-Boreal as long as open grass communities survived in the Kłodnica catchment.
The next phase, in the Late Pre-Boreal and Boreal, is characterized by a significant increase in accumulation
rate of biochemical facies.. The considerable restriction of minerogenic deposition was connected
with widespread of forest and gradual limitation of the river discharges. The third stage began
at the decline of the Boreal and was defined by decrease of accumulation rate or even biogenic accumulation
break. Synchronously, periodic increases of fluvial activity were noticed in the form of cutoffs
of meander loops and overbank deposition in oxbows. The beginning of the fourth period took
place not earlier than in the Early Sub-Boreal. This stage was distinguished by renewed peat
growth/increase in biochemical accumulation rate and periodic increase in alluviation, generally taking
place in the conditions of low channel-forming flows. The latest phase (from the Middle Sub-
Atlantic till now) is characterized by common initiation of slope deposition and a rapid increase in
fluvial sedimentation, especially overbank and tributary fan facies. An increase in minerogenic deposition
occurred in response to human impact, which became more significant from the Roman Period
and occurred on a large scale from the early Middle Ages. Older settlement phases, including intense
settlement from the Hallstatt Period, were not clearly recorded in the Kłodnica valley fill. |