Karol Rotnicki
Articles
Main phases of erosion and accumulation in the Prosna valley in the last glacial-interglacial cycle
Geographia Polonica (1988) vol. 53, pp. 53-66 | 
Full text
Abstract
The problem of associating the main phases of erosion and accumulation in rivervalleys with specific climatic phases of the glacial-interglacial cycle has been known for along time (Soergel 1921; Penck 1938; Trevisan 1949; Jahn 1956a, b; Schumm 1965;Rotnicki 1974a; Kozarski and Rotnicki 1977, 1978, 1983; Starkel 1983). In the initialperiod of the investigation of this problem the prevailing view was that expressed bySoergel (1921), among others, that conditions existing in cold periods of the Pleistocenefavoured intensive accumulation in river valleys resulting in high valley filling. By thesame view, interglacial periods were characterized by deep erosion.
As the time passed, newer and newer studies kept modifying this view. Jahn(1956a, b) expressed the opinion that the erosion phase appears twice in theglacial-interglacial cycle: first at the turn of an interglacial and a glacial, and then at thetransition from the glacial to a temperate period. Schumm (1965) presents a somewhatdifferent view on this problem. According to him, the erosion appears in a late glacialand keeps operating well into early phase of an interglacial, and the tendency towardsvertical stabilization of valley floors appears in the optimum of the interglacial. He is ofthe opinion that in interglacial periods accumulation and aggradation cannot be tracedin river valleys. They appear only at the beginning of a next cold period. There is noerosion phase between those of interglacial stabilization and cold aggradation assumedby Jahn (1956a, b).
Later, opinions on this matter underwent further evolution, especially concerningthose river valleys which were directly affected by the recession of the last inland ice. Insuch valleys the phase of deep erosion took place much earlier, viz. when deglaciationstarted, that is, about 18000 years BP. This was pointed out by Rotnicki (1966, 1974a),Galon (1968), Maruszczak (1968) and Różycki (1972). It should also be added thatopinions concerning Holocene tendencies of fluvial processes are not as undivided asthose referring to Pleistocene interglacial periods.
, Quaternary Research Institute, Adam Mickiewicz University, Poznań, Poland
Geographia Polonica (1969) vol. 17, pp. 231-248 | Full text
Abstract
A considerable growth of interest in the problem of eolian phenomena in West-Central Poland could be traced in the course of the last decade. As a result, numerous papers dealing with this subject have been pu-blished. The growing interest has been followed by a broadening of the scope of problems under consideration. Whereas in previous publications morphological features of the dunes as well as the structural and textural features of their sands has been accentuated, the more recent works are rather concerned with problems of chronology of phases of intensive eolian activity leaving their marks not only in the relief, but also in the formation of cover deposits and the fossilization of Late Würm ice-wed-ges. Thanks to detail investigations in a large number of sites (Fig. 1) the relation between dune sands and peats has been established; in ad-dition, fossil soil appearing in dunes have been examined. The age of peats and fossil soils was determined by means of the pollen analysis, and in some sites archeological materials and radiocarbon 1 dating have also been used as age indicators.
The facts gathered allow for assuming that the main, climate-condi-tioned phases of eolian activity coincided with the Late Würm cold pe-riods. Eolian activity in Holocene, was limited in space, and not caused by climatic changes, but by man intervention in the geographical en-vironment.
, Committee of Geographical Sciences, Polish Academy of Sciences
, Department of Plant Taxonomy and Geography Adam Mickiewicz University Poznań
, Quaternary Research Institute, Adam Mickiewicz University, Poznań, Poland
, Quaternary Research Institute, Adam Mickiewicz Universitety, Fredry 10, 61-701 Poznań. Poland