- Tytuł:
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Rzeźba podczwartorzędowa okolic Szydłowca. Rola litologii i tektoniki
Sub-quaternary relief in the region of Szydlowiec. The role of tectonics - Autorzy:
- Kosmowska-Suffczynska, D.
- Powiązania:
- https://bibliotekanauki.pl/articles/2085672.pdf
- Data publikacji:
- 1988
- Wydawca:
- Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych
- Tematy:
-
Szydlowiec
rzezba podczwartorzedowa
litologia
tektonika
budowa geologiczna - Opis:
- The present article is an analysis of the relief of the Quaternary substratum, this relief being a background for further geomorphologic studies, particularly concerning the way of glaciation and deglaciation of the Riss Glaciation. The investigated area lies on the NE border of the Holy Cross Mts between Skarżysko-Kamienna and Szydłowiec (Fig. 1). On the SW it adjoins the Goleniów Ridge of the Końskie Hills, on the NE it passes into the Quaternary Radom Plain. Such a situation of the area determines certain features of its relief - namely the occurrence side by side, or the overlap-of two relief types of different age – rock relief and Quaternary relief. The rock relief is here much differentiated depending on the lithology; it is different within the Lower Jurassic, the Middle Jurassic and the Upper Jurassic (Fig. 3). Tectonics have also strongly influenced the relief (Fig. 5). In the Quaternary relief a prevailing feature is the occurrence of a number of irregularly scattered glacial hills. They owe their origin to the Riss ice-sheet at the time of its maximum extent. That glacier invaded the rock relief devoid (except valleys) of older glacial deposits. Basing on the map of the Sub-Quaternary relief which she has drawn (Fig. 8) and on cross-sections (Figs 7, 9), the author considers the question to what extent this relief depends on the tectonics of that area and to what extent it is conditioned by its lithology, i.e. what is the share of endogenous and exogenous factors. The sub-Quaternary relief, the same as that of today, generally slopes down from SW to NE, from a maximum altitude of 260 m to 200 m above sea level. The investigated area is cut by the valleys of the Szabasówka and the Iłżanka rivers the bottoms of which descend to 160 m above sea level. The smallest differences of altitude between the fossil sub-Quaternary surface and the present-day relief occur within the Lias rocks, i.e. in the SW part of the area, while the greatest ones - within the Malm rocks in its NE part. In the sub-Quaternary relief some units may be distinguished. The highest part of the area is occupied by a Lias plateau, mainly built of sandstone and mudstone, reaching 260-230 m of altitude. It is relatively flat and vast, with its edges cut by radially parting valleys, on the South it is limited by the valley of the Oleśnica (tributary of the Kamienna). The next element of the relief is a distinct slope of the Lias surface running in accordance with the line of a large dislocation, stretching far and called the Lubień-Mnichów dislocation (Fig. 6). The slope falls towards the valleys of the Szabasówka and the Iłżanka. Those valleys lie in the Dogger clays. Their rocky bottoms lie 30 m below the present-day bottoms. The valley of the Szabasówka is lengthened to the North by a sub-questa valley described by S. Z. Różycki (1972). Another distinct unit in the sub-Quaternary relief is a surface built of much differentiated Dogger rocks, varying from resistant to easily dicayed. A characteristic feature here is the occurrence of elevated, isolated heights; their longer axis (NW-SE) runs conformably to the main tectonic directions. They are built of sandstone series and their relative height reaches ca 50 m. As can be seen on the geologic map (without the Quaternary) (Fig. 3) those hills are inscribed into the network of tectonic transversal and longitudinal lines. The less resistant, clayey strata of the Dogger constituted the foundation of valley. These valleys were deeply cut and avoided rocky hummocks, forming probably a picturesque scenery. The next relief unit is the area lying eastward of the Szabasówka valley. Here the Quaternary substratum is partly built by Tertiary deposits which mask the sub-Tertiary relief. They fill the depressions mainly situated between the outcrops of the ore-bearing horizons of Czerwona and Mikołaj (the Bathonian and the Callovian) and in the border zone of the Dogger and the Malm. The thickness of Tertiary deposit reaches 25 m, their top lies at 190-210 m of altitude and the deepest bottom occurs at 165 m above sea level. The depressions in the Dogger rocks were very narrow and deep, their direction follows the direction of longitudinal dislocation lines. This type of relief can be observed in the area near Mirów (Figs 10, 11, 12). Owing to a thick network of borings it was possible also here to find one of the transversal tectonic lines. It runs crosswise to the strike of strata and has a NE-SW direction conformable to the tectonic lines drawn by Karaszewski (1961, 1975). The thrust value is 22 m at least. The worst known is the sub-Quaternary relief within the last of the distinguished units, i.e. on the area built of Malm carbonate rocks which occupy the NE edge of the studied region. The altitudes of the rocky substratum range from 180 to 195 m above sea level. The area is a plain with an outline of a vast depression without outflow. Owing to its geological structure the area is waterless. In her investigations on the origin of the sub-Quaternary relief the author has paid attention to the age relation - between gradational processes, which resulted here in the formation of the levelling Palaeogene surface, and tectonic occurrences (continuous and discontinuous deformations). There is no visible influence, in the relief, of continuous tectonics (anticlines, synclines). Instead, these tectonics have influenced the direction of the lithologic features of the area. The influence of discontinuous tectonics appears mare directly. Conformably to the run of the Wierzbnik-Chlewiska dislocation the Holy Cross Mts end and the upland begins. Along the next longitudinal dislocation there occurs a distinct, though gradual lowering of the surface built of Lias. The share of transversal dislocations in shaping the sub-Quaternary relief has also been considerable. Through frequent shifting of different parts of the area in relation to one another the transversal dislocations broke the lithological continuity of the particular outcrops and prevented the formation, on a larger scale of erosive and denudative forms of the cuesta type, which are common on the NE border of the mountains. The style here is that of horst relief with characteristic fault blocks cut by dislocations on two or three sides. The influence of tectonics may be also seen in the valley directions in the investigated area (Fig. 2). The directions of even small valleys reflect the directions of faults lines both transversal and longitudinal. This often results in an anomalous system of valleys which are perpendicular to one another. The author considers the problem of tectonic conditioning of the valleys run to be of great importance as she thinks they could have decided on the directions of water drainage from the dying ice and thus on the deposition and extent of glacial forms. It is also worth noting that the system of major roads and villages, through adaptation to the line of hills and valleys, has maintained the directions of the tectonic lines (Figs 1, 3). In answer to the question put at the beginning of the present paper concerning the role of tectonics and lithology in the formation of the sub-Quaternary relief, it should be stated that in the author’s opinion tectonics were of decisive importance through: directing lithological features of the area, imposing places for valley formation, preventing the development of cuestas, the formation of horst relief. Instead, lithology found its expression and influenced the further development of the relief only in places designated by tectonics.
- Źródło:
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Prace i Studia Geograficzne; 1988, 09; 13-52
0208-4589 - Pojawia się w:
- Prace i Studia Geograficzne
- Dostawca treści:
- Biblioteka Nauki
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