Filip Duszyński

Abstract ‘Rock cities’ – a geomorphological term widely used in Czechia, but hardly formalised elsewhere – are spectacular rock-cut landscapes consisting of closelyspaced residual rock blocks separated by narrow intersecting corridors, imparting an overall visual resemblance to an urban landscape. The heights of the rock blocks in question – as compared with the floors of the corridors and passages – may reach many tens of metres. These landforms are known in a wide range of lithologies, including limestones, dolomites, conglomerates, tuffs and granites; but they are particularly well developed in regularly jointed sandstones which support a plateau and cuesta morphology. Typical geomorphic settings of rock cities are marginal parts of plateaus, backslopes of cuesta ridges and top parts of residual hills (mesas). Examples of sandstone rock cities from south-west Poland include the mesa of Szczeliniec Wielki and the plateau of Skalniak (the socalled Błędne Skały rock labyrinth, Dziedziniec), whereas they are even better represented in the adjacent part of Czechia (at the Adršpach and Teplice ‘Rock Cities’ and Ostaš). Further rock cities can be found in northern Czechia, within an extensive tableland built of Upper Cretaceous sedimentary formations, chiefly sandstones, and then in Saxony, Germany. The origin and evolution of the ‘rock cities’ are primarily controlled by structure, i.e. the pattern of discontinuities within the rock mass. These, preferentially eroded due to mechanical weakness, turn into ‘streets’, and into ‘squares’ at their intersections. However, the rock mass itself has to be strong enough to support steep to vertical rock faces, and in sandstones the strength is the combined result of wide joint spacing in certain sandstone variants and the presence of surface crusts of chemical and biochemical origin. The latter prevent steady grain-by-grain disintegration. A wide range of processes are thus involved in the formation of sandstone ‘rock cities’, including surface and subsurface weathering (including silica dissolution), mass movements of different types, underground erosion (piping), and subordinately fluvial erosion and aeolian abrasion. Despite these being spectacular landscapes, very few models of long-term evolution of ‘rock city’ and ruiniform relief have been presented in the literature, and it is anyway unlikely that any one scenario would apply to all situations. Rather, ‘rock cities’ are most probably examples of geomorphological convergence.

Keywords: geomorfologia strukturalna, rzeźba piaskowcowa, erozja podpowierzchniowa, ruchy masowe

Filip Duszyński [filip.duszynski@uwr.edu.pl], Uniwersytet Wrocławski, Instytut Geografii i Rozwoju Regionalnego
Piotr Migoń [piotr.migon@uwr.edu.pl], Institute of Geography and Regional Development University of Wrocław Pl. Uniwersytecki 1, 50-137 Wrocław: Poland

Citation

APA: Duszyński, F., & Migoń, P. (2018). Geneza skalnych miast na płaskowyżach piaskowcowych. Przegląd Geograficzny, 90(3), 379-402. https://doi.org/10.7163/PrzG.2018.3.1
MLA: Duszyński, Filip, and Migoń, Piotr. "Geneza skalnych miast na płaskowyżach piaskowcowych". Przegląd Geograficzny, vol. 90, no. 3, 2018, pp. 379-402. https://doi.org/10.7163/PrzG.2018.3.1
Chicago: Duszyński, Filip, and Migoń, Piotr. "Geneza skalnych miast na płaskowyżach piaskowcowych". Przegląd Geograficzny 90, no. 3 (2018): 379-402. https://doi.org/10.7163/PrzG.2018.3.1
Harvard: Duszyński, F., & Migoń, P. 2018. "Geneza skalnych miast na płaskowyżach piaskowcowych". Przegląd Geograficzny, vol. 90, no. 3, pp. 379-402. https://doi.org/10.7163/PrzG.2018.3.1

Abstract The Stołowe Mountains,situated in the Middle Sudetes, form Poland’s only tableland, which is underlain by an alternating succession of sedimentary rocks, all of Permian and Late Cretaceous age. The morphology of the Stołowe Mountains is characterised by the presence of isolated mesas and plateaus. Nearly-level summits are bounded by precipitous escarpments up to 300 m tall. These are bipartite in profile, with stronger sandstones forming vertical cliffs and less-resistant marls and mudstones being truncated by concave slope sections. There seems to be general agreement that long-term escarpment retreat is the dominant pathway by which this tableland evolved geomorphically. However, ideas on the processes contributing to the scarp recession vary. Since the early 20th century, the dominant concept has ascribed a major role to catastrophic mass movements. Łoziński (1909) for example pointed to rock falls, and linked their origin with intense mechanical weathering. For their part, both Czeppe (1952) and Dumanowski (1961, 1967) underlined the crucial importance of subsurface water flow at the point of contact between the permeable sandstones and impermeable fine-grained rocks. In their opinion, that phenomenon results in the undercutting and destabilisation of rock faces. Pulinowa (1972, 1989) was of a similar view and suggested that plastic deformations of underlying marls and mudstones caused subsidence and the toppling of marginal parts of the sandstone caprock. Although deep clefts are a prominent feature of Mt Szczeliniec Wielki, no significant movements have been recorded in recent decades (e.g. Cacoń, 2008). Thus, from a present-day standpoint, the different outlooks mentioned above can be considered highly influenced by paradigms, while lacking in support where empirical data are concerned. In contrast, systematic study based on quantitative measurements has been engaged in recently by Duszyński and Migoń (2015) and Duszyński et al. (2016). They reveal that non-catastrophic disintegration of cliff lines appears to be a much more common phenomenon than rock failure. An alternative scenario assumes that the marginal parts of plateaus are separating along joints, due to underground erosion and removal of rock residuum. In this way, after a long period of time, a once-solid rock face becomes a mess of joint-bounded blocks. Transport downslope is then more apparent than real as progressively lower topographical positions are occupied, while the lower escarpment slope recedes. Landslides in the middle and lower parts of the slope (Duszyński et al., 2017), block ploughing (Pulinowa, 1989; Duszyński and Parzóch, 2016) and erosional incision (Migoń and Kasprzak, 2016) all do contribute to escarpment retreat, but their role is limited to single localities. Although our knowledge regarding the evolution of the Stołowe Mountains has improved greatly, we still lack chronological data, and are hence unable to pinpoint the environmental conditions proving particularly favourable to escarpment recession. There is also a need to determine whether the arenisation process often described in the foreign literature (e.g. Wray and Sauro, 2017) is actually responsible for the slow detachment of sand grains from quartz sandstone.

Keywords: Góry Stołowe, progi morfologiczne, procesy rzeźbotwórcze, historia badań

Filip Duszyński [filip.duszynski@uwr.edu.pl], Uniwersytet Wrocławski, Instytut Geografii i Rozwoju Regionalnego

Citation

APA: Duszyński, F. (2018). Mechanizmy i uwarunkowania rozwoju progów morfologicznych Gór Stołowych. Przegląd Geograficzny, 90(1), 7-33. https://doi.org/10.7163/PrzG.2018.1.1
MLA: Duszyński, Filip. "Mechanizmy i uwarunkowania rozwoju progów morfologicznych Gór Stołowych". Przegląd Geograficzny, vol. 90, no. 1, 2018, pp. 7-33. https://doi.org/10.7163/PrzG.2018.1.1
Chicago: Duszyński, Filip. "Mechanizmy i uwarunkowania rozwoju progów morfologicznych Gór Stołowych". Przegląd Geograficzny 90, no. 1 (2018): 7-33. https://doi.org/10.7163/PrzG.2018.1.1
Harvard: Duszyński, F. 2018. "Mechanizmy i uwarunkowania rozwoju progów morfologicznych Gór Stołowych". Przegląd Geograficzny, vol. 90, no. 1, pp. 7-33. https://doi.org/10.7163/PrzG.2018.1.1

Abstract The aim of this review has been to describe the phenomenon of the dendrochronological recording of air pollution. Special emphasis was placed on: (1) summarising relevant studies conducted previously both in Poland and abroad, (2) highlighting the research techniques applied most commonly, and (3) presenting the basic physiological and morphological consequences of the exposure of plants to harmful chemical substances present in the air. Although the problem of growth–ring reductions to industrial emissions has gained frequent investigation (e.g. Danek, 2007; Szychowska-Krąpiec, 2009; Malik et al., 2011, 2012), this paper would seem to represent a first attempt to review the achievements of the method in the Polishliterature.The dendrochronological method is widely regarded as the most precise dating technique in the Earth Sciences (e.g. Gärtner, 2007). As the final width of a single tree-ring refl ects both genetics and certain external factors, it is possible to make reference to rings in studying the spatial and temporal differentiation characteristic of various environmental phenomena. Since the 1970s, it has become clear that air pollution episodes may be recorded effectively in tree-ring series. Such chemical substances as sulphur dioxide, oxides of nitrogen, fluorides and ozone are all toxic to plants, inasmuch as that they individually and collectively exert a negative influence on key physiological processes. They are thus responsible for patterns of reduced growth that can be dated with the year-to-year accuracy by means of dendrochronological techniques.Over the last forty years, much work around the world has been devoted to the above problem. Most has focused on study of the impact of harmful gaseous substances emitted from such point sources as smelters (e.g. Sutherland and Martin, 1990; Nojd and Reams, 1996) or fertiliser factories (e.g. Evertsen et al., 1986; Stravinskiene et al., 2013). Beyond that, some works haverepresented a broader approach researching air pollution impacts on a regional or international scale (e.g. Danek, 2007; Elling et al., 2009). In each case, the results reveal a more or less serious reduction of tree-rings corresponding well with periods of low air quality.The range of techniques gaining application in the studies described has been wide, though in the main it is the more complex ones that have generated more precise and reliable results. The simplest method is based on visual assessment of a curve showing the width of tree-rings over time. Visible, persisting low values combined with knowledge of the activity of some factory in the vicinity can lead to the drawing of conclusions as regards the causal relationship. Much fi eldwork is tailored to the sampling of reference (control) sites, not affected by air pollutants. Data from the study and the reference site are then compared using different statistical methods. Narrower rings formed by trees growing at the study site are taken to confirm thepresence of a phenomenon reflecting emissions from local industry. Another method, proposed by Schweingruber et al. (1985), is based on the analysis of characteristic years and abrupt growth changes.

Keywords: dendrochronologia, zanieczyszczenie powietrza, bioindykacja powietrza

Filip Duszyński [filip.duszynski@uwr.edu.pl], Uniwersytet Wrocławski, Instytut Geografii i Rozwoju Regionalnego

Citation

APA: Duszyński, F. (2014). Zapis zanieczyszczenia powietrza w przyrostach rocznych drzew. Przegląd Geograficzny, 86(3), 317-338. https://doi.org/10.7163/PrzG.2014.3.2
MLA: Duszyński, Filip. "Zapis zanieczyszczenia powietrza w przyrostach rocznych drzew". Przegląd Geograficzny, vol. 86, no. 3, 2014, pp. 317-338. https://doi.org/10.7163/PrzG.2014.3.2
Chicago: Duszyński, Filip. "Zapis zanieczyszczenia powietrza w przyrostach rocznych drzew". Przegląd Geograficzny 86, no. 3 (2014): 317-338. https://doi.org/10.7163/PrzG.2014.3.2
Harvard: Duszyński, F. 2014. "Zapis zanieczyszczenia powietrza w przyrostach rocznych drzew". Przegląd Geograficzny, vol. 86, no. 3, pp. 317-338. https://doi.org/10.7163/PrzG.2014.3.2