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This research sought to indicate changes in the area of plant communities designated for protection in part of the middle Vistula river valley. The study concerned the 50-year period 1949-2001, with the changes registered cartographically. The study area (about 905 km2) is located between the Sanna confluence above Annopol and Góra Kalwaria (from km 295 to km 482 of the river course). The analysis of changes determined the general trends of the natural environment transformation in the second half of 20th century that helped to indicate areas that should be protected additionally. Nineteen types of habitats listed in legal statutes (Habitats Directive etc.) were identified in the chosen part of the valley. Over 50 years, grassland communities have undergone the most significant modifications. Vegetation changes reveal a tendency of a lowering of the water level or a change in the horizontal movement of water as well as of aggradation (increased sediment accumulation) in the river-channel. There are indications that two specific areas should be protected additionally because of the definite presence of valuable natural habitats.
Within the channel zone of the Middle Vistula River, elevations of the Holocene alluvial basement occur, composed of deposits resistant to erosion. In this paper two kinds of such forms are discussed. Within the Małopolska gorge (an upstream part of the Middle Vistula, near Kępa Gostecka and Zakrzów), the elevations are composed mainly of Upper Cretaceous and Paleogene rocks covered with clayey debris and residual lags. Below this, the elevations are built of Paleogene and Neogene soils as well as of various Pleistocene glacial deposits, and are of ten covered by residual lags. This type of valley stretch occurs in the vicinity of Dęblin. The surface of the erosion-resistant Holocene alluvial basement averages at 5-7 m below the mean water level. It is exposed on the channel bottom during high-water stages, as seen from a residual layer and from the low density of the contemporary channel deposits above them. The morphology of these elevations influences the pattern of the main stream also during mean-water stages. The trend to flood flow concentrations is also seen in the relief of the floodplain.
Content available remote Palinologiczny zapis trzeciorzędu w dolinie środkowej Wisły
Ter tiary depos its in the Mid dle Vistula River val ley have been paly no logi cal ly stud ied. Sed i ments were inves ti gated dur - ing research for sev eral sheets (Dęblin, Kozienice, and Puławy) of the Detailed Geo log i cal Map of Poland in 1: 50,000 scale —. Seven palynological assem blages were rec og nized, con tain ing Upper Paleocene, Mid dle and Upper Eocene, Lower Oligocene, and Mid dle Mio cene palymomorphs. In the Paleogene marine depos its, a rich dinocysts assem blages becomes palynological marker, sporomorphs are less numer ous. In the Neo gene, sporomorphs are abun dant. Phytoplankton assem blage from the Paleocene depos its show pre dom i - na tion of marine coastal facies. Palynomorphs from Eocene sed i ments were depos ited far ther from the shore. The lower Oligocene assemblage was characteristic for brackish deposits with substantial admixture of sporoporphs and phytoclasts of continental origin . Middle Miocene sporomorphs characterize two types of vegetation assemblages. Lower parts of the Middle Miocene (VI Tricolporopollenites megaexactus zone) contain pollen grains from shrubby peatbogs and mixed mesophilous forest, indicating warm and dry climate. Upper part of the Middle Miocene (IX Tricolporopollenites pseudocingulum zone), dominating plant communities were swamp and riparian forest, thus indicating warm and wet climate.
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