Analysis of benchmark height changes along national 1 st order precise levelling lines crossing the Middle Odra Fault Zone in the Wroclaw area has been presented in this paper. The zone separates Fore-Sudetic Block from the Fore-Sudetic Monocline and is one of the main geological structures in Lower Silesia. Five national precise levelling lines cross the research area: Ząbkowice Śląskie – Wroclaw, Sycow – Wroclaw, Karczow – Wroclaw, Kawice – Wroclaw oraz Krotoszyn – Wroclaw. These levelling lines were measured in 1956-58, 1975-80 and 1999. Changes of benchmark heights have been presented in comparison with geological cross-sections made along the levelling lines. In the result, areas of the greatest relative vertical displacements correlated with geology and tectonics have been found.
Terraces of Nysa Klodzka river and small-scale tectonic structures close to the Sudetic Marginal Fault at Janowiec (Bardo Mts.). S u m m a r y . New research in the N part of the Bardo Gorge (close to the Sudetic Marginal Fault) evidenced the occurrence of two hitherto unknown Pleistocene river terraces. The terraces were interpreted basing on digital elevation model (DEM) 1:10,000 and radars sweeping of the Earth’s surfaces (DETM level 2). Moreover, the results of petrographical analysis of deposits exposed in the 22 high river terrace show two-tier structure of the terrace. This suggest a polygenetic age of the terrace. Within the last terrace fractured clasts and small-scale faults were observed. Fractured clasts were studied in the bottom part of the 22-m-high river terrace where numerous fractured clasts occur. This part of the terrace is composed of gravels containing clasts up to 80 cm across. The matrix is sandy-clayey. The fractures are usually restricted to particular clasts. The fractures compose two sets striking NW-SE and N-S. Gravels exposed in the uppermost part of the terrace are cut by few strike-slip, N-S striking, sub-vertical faults which can be traced along a vertical distance up to 50 cm. These faults cut the gravel matrix but omit clasts. Fractures cutting the clasts do show a well organized architecture which is independent of orientation of a-b surfaces of the host clasts. These features indicate that the fractures were formed in situ within the studied gravels. Furthermore, for the majority of fractures, the angle between the fracture and the a-b surface of the host clast is less than 80o, confirming the in situ origin of fractures. The fractures of one set are parallel to the strike of the Sudetic Marginal Fault. This suggests that the origin of the fractures is related to that of the fault. The fractures of the second set may represent Riedel shears associated with the activity of the Sudetic Marginal Fault. The orientations of minor faults confirm this supposition. Summing up, we believe that during the Pleistocene, the Sudetic Marginal Fault was a dextral strike-slip fault, at least in the discussed area.
We analysed a nearly 133-km-long portion of the Sudetic Marginal Fault (SMF) in Poland (99.7 km) and the Czech Republic (33.8 km), comprised between Zlotoryja in the NW and Jesenik in the SE. The fault trace has been subdivided into fifteen segments showing different orientation (N29°W to N56°W, and even N111°W SE of Zloty Stok), geological setting, length (8.8-22.9 km in Poland and 1.4-7.5 km in the Czech Republic), and height of the fault- and fault-line scarps (5-75 m to 200360 m). Orientation of the entire fault trace approaches N41°W, and the mountain front sinuosity amounts to 1.051. Individual fault segments bear a flight of two to five tiers of triangular facets, showing differentiated state of preservation and degree of erosional remodelling. The highest triangular facets are confined to Rychlebske (Zlote) and Sowie Mts. This tiering points to at least five episodes of uplift of the SMF footwall, starting shortly after 31 Ma, i.e. after basalts of the Sichow Hills area were displaced by the fault, and most probably postdating 7-5 Ma time interval, during which rapid cooling and exhumation of the Sowie Gory Mts. massif took place. Morphometric parameters of 244 small catchment areas of streams that dissect the fault scarp include, i.a. elongation, relief, and average slope of individual catchment areas, together with values of the valley floor width to valley height ratios. These figures point to moderate tectonic activity of the SMF and allow us to conclude about Quaternary uplift, particularly important in the Sowie and Rychlebske (Zlote) segments.
SEDIMENTOLOGICAL AND PALAEOBOTANICAL RECORDS OF CLIMATIC CHANGES WITHIN PLIOCENE FLUVIAL SEDIMENTS IN THE SOUTHEASTERN SILESIAN LOWLAND Abstract. Neogene fluvial deposits of the Gozdnica Formation constitute a continuous cover in the southeastern part of the Silesian Lowland, in the Nysa Klodzka and Odra interfluve. The 18 m thick succession of these deposits was studied in the Tulowice site on the Niemodlin Plain. Heavy mineral analysis indicates that deposits of the lower part of the succession were probably accumulated by the Nysa Klodzka River, and those of the upper part — by the Odra River. Detailed sedimentological research was conducted in an excavation where the latter deposits are exposed. Four lithologic complexes were distinguished. It was found that three older complexes were formed mostly ha a meandering river system. The deposits of complex 4 represent alluvium of an anastomozing river system. Palaeobotanical analyses were made for silty-clayey deposits of complexes 1 and 2, and revealed plant cover variability indicating a climatic tendency for short-term oscillations of mean temperatures and humidity. Pollen spectra evidenced Pliocene age of the deposits under study. Both sedimentological and paleobotanical data indicate that the change of fluvial environment could have been associated with a progressive climatic change during the Late Pliocene, directly preceding the Early Pleistocene cooling.
The results of a comprehensive study of Pleistocene fish‐bearing localities from the territory of Poland are presented. Fish remains came from lacustrine deposits and cave sites representing a time‐span from the late Early Pleistocene until the Early Holocene. Here we present the taxonomic composition and species diversity of all known fish assemblages from Poland. In total, 23 species belonging to 20 genera of eight families were identified. Cyprinids were the most taxonomically diverse, followed by salmonids and percids. Other families were each represented only by a single species. The roach, rudd, bream, pike and perch were the most common components of the Pleistocene fish assemblages of Poland. These assemblages are clearly divided into two groups representing palaeolakes and cave sites. A significant taxonomic similarity is observed between fish assemblages from Poland and those of Chibanian and Late Pleistocene ages from central and eastern Europe. Pleistocene environments and climates of Poland are characterized using a multi‐proxy approach (analysis of stable isotopes, plant macro‐remains, pollen, molluscs and cladocerans). Obtained data allowed us to estimate a number of parameters of Pleistocene water bodies of the Polish Lowland (reservoir type, trophism, oxygen content, depth and water level changes, bottom character, and flow speed). The formation of freshwater fish assemblages was influenced by dynamic changes in the hydrographic network, and climatic changes during the Pleistocene and Holocene. Their development was favoured by the formation of lakes after melting of the ice sheet.
