Geographia Polonica (2008) vol. 81, iss. 1
Modelling of high-mountain relief
Geographia Polonica (2008) vol. 81, iss. 1, pp. 7 | Full text
Geographia Polonica (2008) vol. 81, iss. 1, pp. 9-18 | Full text
Valuable estimates of Holocene solutional erosion rates are offered by ice-scouredlimestone pavements which provide adequate reference surfaces and reliable chronological control.From Spitsbergen to the equatorial mountains and hyperhumid Chilean Patagonia, increasingrates of surface lowering due to carbonate solution coincide with increasing precipitationamounts. Additional data from other environments confirm the primacy of this climatic control,but also point to the need for rock control (e.g. porosity and jointing) to be taken into accountin comparative studies. As shown by Goldie (2005), when obtained in densely jointed and/orbedded limestones, the so-called ‘solution rates’ correspond to rates of mechanical weatheringand cannot be compared to genuine solution rates obtained on compact and massive carbonateoutcrops.
, Laboratory of Physical and Environmental Geography GEOLAB—UMR 6042 CNRS / Blaise Pascal University MSH 4 rue Ledru 63057 Clermont-Ferrand Cedex 1 (France)
Geographia Polonica (2008) vol. 81, iss. 1, pp. 19-28 | Full text
The occurrence of permafrost in the Italian Alps is an important predisposing factorfor landslides. Debris flows are frequent on slopes overlying permafrost and are likely the resultof active-layer supersaturation. The role of permafrost degradation in triggering landslides fromhard rock slopes as a response to climatic warming has been pointed out only recently. Geotechnicalinvestigations demonstrate that ice-filled fractured rock slopes at temperatures between–2° and 0° C are less stable than when in an unfrozen state. The Val Pola rockslide, whose accumulationmass included ice-cemented blocks, could be explained therefore as the result of strengthreduction along pre-existing potential sliding surfaces, filled with warming ground-ice.
, Department of Structural and Functional Biology, Insubria University via J H. Dunant, 3-21100 Varese, Italy
Geographia Polonica (2008) vol. 81, iss. 1, pp. 29-40 | Full text
Mountain-top detritus characterizes the two high summits of the Gaspésie Mountains,eastern Canada. It is suggested that these angular rock-rubble accumulations developed from thedisintegration of coarse-grained igneous bedrock exposed to thermal stress and ice segregationduring prolonged episodes of permafrost formation in the cold periods of the Pleistocene. Frostwedging and frost heaving (‘jacking’) were the primary mechanisms. Today, climatic conditionson the summits permit only thin and marginal permafrost bodies. Stone nets and stripes aredeveloped where a residual bedrock-derived debris mantle is present. They reflect frost-inducedmovements within the active layer. The latest of these movements probably occurred during thecold period following the LGM and persisted into the mid-Holocene. The transition from nets tostripes relates to slope angle.
Geographia Polonica (2008) vol. 81, iss. 1, pp. 41-52 | Full text
This paper attempts to determine the relationship between multi-annual variability of airtemperature, precipitation and wind velocity, and changes in the front limits of the perennialfirn-ice forms (glacierets) developing under different topographic conditions. Problems with thepalaeoclimatic interpretation of their internal structure are also discussed. The obtained resultsattest to the fact that fluctuations in firn-ice patches in the Tatras are probably most connectedwith the weather regimes in winter seasons. Similar changes of individual forms depend on theirsimilarity in terms of type of snow accumulation and the altitude at which they are located.
, Faculty of Earth Sciences University of Silesia in Katowice Będzińska 60, 41-200 Sosnowiec: Poland
Geographia Polonica (2008) vol. 81, iss. 1, pp. 53-66 | Full text
The energy of high-mountain georelief is evidently transformed into intensity and rangeof impact of gravitational, water- or snow-induced processes, cryogenic processes, solifluctionand deflation. The altitude and climatic conditions of the alpine zone allow for the conservationof some relict or development of some recent processes in the periglacial environment. This paperpresents the results of direct measures of some geomorphic processes acting, or said to be active,in the alpine area of the Tatra Mountains. Measurements of debris flows and debris slides, aswell as of eolian-nivational, solifluction and ploughing boulder processes, have been conductedat 25 sites distributed across: the Jalovecká Valley in the Western Tatra Mts. of Slovakia, as wellas the source area of the Predné Meďodoly and Zadné Meďodoly Valleys in the Belianske Tatry.The results have been compared with those from previous observations.
email@example.com], Department of Ecology and Environmentalistics Faculty of Natural Sciences Constantine the Philosopher University in Nitra
[firstname.lastname@example.org], Department of Ecology and Environmentalistics Faculty of Natural Sciences Constantine the Philosopher University in Nitra
, Institute of Landscape Ecology SAS Bratislava, branch in Nitra Akademická 2, 949 01 Nitra, Slovakia
, Institute of Landscape Ecology SAS Bratislava, branch in Nitra Akademická 2, 949 01 Nitra, Slovakia
Geographia Polonica (2008) vol. 81, iss. 1, pp. 67-78 | Full text
The Monts Dore massif is a typical high-mountain area with nival relief dominant abovethe timberline. The massif is situated at the centre of the Massif Central and constitutes its highestpart. Nivation, cryogenic processes and deflation are the key morphogenetic processes, butrunoff action, especially on slopes with deteriorated vegetation cover, plays an equally importantrole due to the dominant maritime climate.
, Institute of Geography, Jagiellonian University, Cracow, Poland
Geographia Polonica (2008) vol. 81, iss. 1, pp. 79-92 | Full text
Rockfall accumulation was measured in 1981 and 2000 along ca. 850 m of the formerBanff-Jasper highway that skirts a large talus cone from Mount Wilcox in Jasper National Park,Alberta. Approximately 34.5 m3 of rockfall debris has accumulated on the roadbed since it wasabandoned in 1961. The largest boulder was 4.65 m3 and 5 others were >0.95 m3. Estimatedminimum accumulation rates from 20–30 m sections of highway adjacent to the base of the coneare mainly between 0.1–0.3 mm yr -1, with rates >0.4 mm yr -1 reflecting the presence of individuallarge boulders. These rates correspond to a thickness of 1–5 m over the Holocene and may bereasonable estimates for deposition at the outer talus fringe of such large cones. Over the observationperiod, approximately 10 rockfalls > 0.25 m “a” axis were deposited on the road eachyear, but only one every two years was > 0.5 m. Much larger rockfalls (up to 6–10 m3) havetraveled across the road, creating bumpholes, and been deposited on the outwash. These resultsindicate some of the problems with trying to estimate rates of contemporary rockfall activity fromsampling programmes based on relatively short periods of time and limited depositional areasbecause of the magnitude frequency distribution of the rockfall events.
, Department of Geography, University of Western Ontario London, Ontario, Canada N6A 3K1
Geographia Polonica (2008) vol. 81, iss. 1, pp. 93-100 | Full text
This article focuses on the rate of present-day retreat of slopes, as determined by directmeasurement, both above and below the upper timberline, and in relation to erosion, mass movements,cryogenic processes, nivation, aeolian processes, etc.Rates of surface erosion processes—the most widespread geomorphic processes operating at highaltitude in the Western Carpathians—range from low to high. In the forest belt below the uppertimberline, in the dwarf pine scrub and on surfaces with grassland, the mean rate of soil removalis of only 0.001–0.007 mm yr -1. In the case of denuded surfaces with destroyed cover this rises to3.4 mm yr -1 on average, while linear erosional landforms lose as much as 17.4 mm yr -1.As a whole, the area above the upper timberline in the Slovak geomorphic units of the WesternCarpathians is characterised by medium to relatively high real denudation rates, the mean rateof slope retreat being 0.27 mm yr -1.
, Institute of Science and Research, Matej Bel University in Banská Bystrica Cesta na amfiteáter 1, 974 01 Banská Bystrica, Slovakia
Geographia Polonica (2008) vol. 81, iss. 1, pp. 101-116 | Full text
The forested mountains ranges of the Bohemian Massif, including the Sudetes, typifymoderately high mountain geomorphology (Mittelgebirge). However, the most elevated partsof the Sudetes also have landscape elements more readily associated with high-mountain relief.These include sub-alpine meadows and bare regolith-covered slopes, a multitude of relict periglaciallandforms, as well as inherited Pleistocene glacial landforms. The present-day geomorphologicalactivity in the terrain located at and above the timberline is much more evident thanthat recorded in the lower forested belt. Debris flows triggered by occasional downpours arethe most potent geomorphic agents, also influencing hydrological conditions and vegetation patterns.Avalanches play a further role in determining the position of the timberline, but rockfallsare very rare. The contemporary development of certain small-scale periglacial landforms hasbeen recognized, and close correspondence is found to exist between the tiered structure of morphogeneticdomains recognized in the Carpathians and the highest massifs in the Sudetes.
, Institute of Geography and Regional Development University of Wrocław pl. Uniwersytecki 1, 50-137 Wrocław: Poland
Geographia Polonica (2008) vol. 81, iss. 1, pp. 117-133 | Full text
This paper concerns itself with the issue of relief and permafrost in mountains in whichthe latter phenomenon is only present in the form of isolated patches, as is the case in the TatraMountains. Thus the slope morphology and morphodynamics at three permafrost sites in theTatra Mts. are discussed in the context of the presence of periglacial landforms, especially indicativeforms of permafrost. No distinct morphological evidence as to the presence of permafrostwas in fact noted.
email@example.com], Institute of Geography and Spatial Organization Polish Academy of Sciences, 31-018 Krakow, Sw. Jana 22, Poland[