Wyniki badań palynologicznych osadów zastoiskowych z Jeleniej Góry

Abstract

THE RESULTS OF PALYNOLOGICAL RESEARCH OF ICE-MARGINAL LAKE DEPOSITS IN JELENIA GÓRASummaryThe palynological research of stratified clays found to occur within the Jelenia Góra basin, madein 1968-1969, concerned the determination of the absolute age of these deposits. Samples for examination were taken in the active brickyard in Jelenia Góra, within the southern part of the town(Fig. 1). 42 samples (10cm apart) were taken from the deposits that underlie the ice-marginal lake clays, referred to Preglacial, and 4 check samples (50 cm apart) – from the morainic clay that overlies the stratified clays (Fig. 2).The Preglacial deposits revealed scarce amounts of pollen grains of Pinus silvestris, Artemisia, Gramineae. On the other hand, rich palynological material was ascertained to occur in the ice-marginal lake clays and in the overlying morainic clays.The spore-and-pollen assemblage from the section of the ice-marginal lake deposits and from the morainic clays of the brickyard in Jelenia Góra is characteristic of both the Tertiary and the Quaternary, although Quaternary sporomorphs are scarcely represented. In the deposits examined, the groupof conifers predominates, among them Taxodiaceae -Taxaceae- Cupressaceae – up to 40%Pinus silvestrisR u d o l p h and Pinus haploxyn R u d o l p h – 30%. Fairly rich are also assemblages of Sciadopitys, Picea, Larix, Nyssa, Quercoidites henrici R. P o t., Juglandaceae. Groups of pollen grains of Castaneoidites exactus, Pollenites liblarensis, Symplocos and Pa1mae appear in more than 10 samples, in an amount of 5%.Groups of the present-day types living in North and Central Europe are scarcely represented by Alnus, Betula, Carpinus, Salix and Tilia. Among herbaceous plants are found: Artemisia, Compositae, Ericaceae, Gramineae and Ephedra. The occurrence of marine microorganisms of “Hystrix”in the deposits examined is worthy of being emphasized here. These specimens were found in the morainic clay and at the top at the ice-marginal lake clays, in an amount of 3%. The representatives of “Hystrix”do not appear in the lowermost part of the section.The palynological analysis of the morainic clays and of the ice-marginal lake formations demonstrated the same composition of sporomorphs; in this way it proved the existing view on the Quaternary age of the deposits considered. The Tertiary sporomorphs found to occur in the deposits examinedare aresult of the erosion, transportation and deposition of these forms inabasin by melting glacier waters. This is evidenced by a lack of macroscopic fragments of plants, the presence of which is always a basis to state that a deposit is in situ. Erosional process affected here the shallow-seated freshwater sediments of Neogene age, developed as brown coals.