Holoceńska sukcesja roślinności w profilach Niechorze III i IVa (Pomorze Zachodnie)

Abstract

Przedstawiono wyniki analizy palinologicznej dwóch profili ze stanowiska Niechorze (III i IVa). Dają one obraz holoceńskiej sukcesji roślinności i poparte datowaniem 14C pozwalają na odtworzenie procesów klimatycznych od młodszego dryasu do okresu subatlantyckiego. Wyniki opracowania mogą być pomocne do określenia wieku maksymalnej transgresji Morza Bałtyckiego w rejonie Pomorza Zachodniego oraz korelacji wiekowych z obszarami południowej Skandynawii.HOLOCENE VEGETATIONAL SEQUENCE IN THE SECTIONS NIECHORZE III AND IVA (WESTERN POMERANIA) Palynological studies on the sections Niechorze III and IVa were carried out as a continuation of the studies on sediments of ancient sedimentary reservoirs Niechorze I and II, cropping out in coastal . cliff in the vicinities of Niechorze (Figs. 1-4), initiated in 1974. The section Niechorze III has been compiled on the basis of results of an exploratory drilling made in 1975 for the Geological Institute, within the frame of works on the Detailed Geological Map of Poland in the scale 1: 50,000, Niechorze sheet. In the scetions Niechorze III and IVa, there were identified sediments of successive time intervals of the Holocene, with relics of characteristic vegetational covers and the Younger Dryas (Niechorze Ill) with relics of vegetation subarctic in character. The Preboreal interval was characterized by development of birch-pine forests with patches of steppe vegetation (section Niechorze IVa), and the Boreal - by predominance of forest assemblages mainly comprising pine and other trees such as Corylus, Quercus, Tilia and Ulmus. In the Atlantic time, the latter trees were luxuriantly growing and predominating in forest assemblages, in which pine and birch were forming subordinate admixtures only. General changes which have taken place in vegetational cover in the Subboreal time (according to 14C datings), were connected with deggradation of hitherto dominating forests. The changes are reflected by an increase in share of pine as well as herbaceous plants. In the Subatlantic time, meadow areas were markedly growing and traces of agricultural activities (corn pollen and weeds) began to appear, which was accompanied by regression of all the trees except for birch and pine. The changes suggest that the Man activity was aimed at deforestation of these areas. The section Niechorze III reflects influence of the Baltic Sea and its role in formation of the studied reservoir. Atlantic sediments of that reservoir yield large admixture of pollen derived from older strata. This seems to evidence some scouring in times of the Littorina transgression in the Baltic. No pollen material was found in fine-grained and silty sands from the depth interval 2.75 - 7.25 m, referable to the Subboreal interval of time. This may be explained by origin of a sand-bar, separating the Niechorze Lake from the sea. The section Niechorze IVa displays continuous and consequent image of successions of Holocene vegetation and it markedly supplements the previously studied Holocene sections.