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Genesis of granite caves in the Krkonoše Mts.
Tomíček, Jiří ; Engel, Zbyněk (advisor) ; Hartvich, Filip (referee)
In the Giant Mountains have been recorded 16 granite caves in total, they can be classified into 4 morphogenetic groups: crevice caves, crevice - collapse caves, talus caves and rockwall niches. The spatial distribution of caves is very irregular - 13 caves in the Pogórze Karkonoskie and 3 in the Giant Mts. ridge. Caves, associated with the rock blocks movements (crevice, crevice - collapse, talus caves), have formed in periglacial conditions by cryogenic and gravitational processes. Rockwall niches have formed by selective weathering along horizontal fractures. The most suitable granite of Giant Mountains is coarse - grained porphyric type, which has an irregular primary joint system and is less resistant to selective weathering. The investigation of a present - day development of Krakonošova klenotnice and Lomená caves in Pančavská jáma cirque should be focused on monitoring of recent rock blocks movements and on relative dating of joint planes.
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Thermal regime of moraine cover in the Adygene valley, Kyrgyz Range
Martinásková, Daša ; Engel, Zbyněk (advisor) ; Uxa, Tomáš (referee)
Submitted Bachelor thesis is focused on thermal regime of the morain covering, which is one of the main indicators of the extension in periglacial and glacial zone in the mountain environment. Introductory part is concluded from themed literature and is primarily focused on the characteristics of the thermal regime of sediments and their relationship to the boundaries of the mountain permafrost, position of equilibrium snow line and temperature-based mountain glaciers. The following sections of this work are describing physical and geographic conditions of the valley of Adygine in Kyrgyz Range area (northern Tien-Shan) as well as the methodologhy of the used work The main part of this document is the evaluation of measured temperature in the morain cover in the area of interest. At first from general point of view, then in terms of freeze-thaw characteristics and finally relate these findings to the local conditions of the glaciál environment. According to the measured results, is it clear that there are many factors influencing the soil temperature regime. Among the most fundamental, the most important include air temperature, local circulation conditions, snow cover and local habitat conditions. Knowledge gained from the practical part shows that the measurement localitions are characterized by...
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Evaluation of physical-geographical research of the High Tatra Mts in the period 1969 - 2008
Jurdík, Michal ; Kalvoda, Jan (advisor) ; Engel, Zbyněk (referee)
This bachelor thesis deals with physical-geographical researches about High Tatra Mts published in 1969 - 2008. It compares recent knowledge about nature of High Tatra Mts. with knowledge published few decades ago. This work describes the most important researches. It also describes this mountain range within it's geomorphological, hydrological, climate, soil and other features. High Tatra Mts. build an exclusive complex of landscape natural components. Lots of landform factors in small area and vertical zonation with variable characteristics makes this area a good model for geographical studies. Key words: physical geography, High Tatra Mts.
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Rockfalls in the Jestřebí Castle area
Kaňková, Helena ; Kalvoda, Jan (advisor) ; Engel, Zbyněk (referee)
Rockfalls in the Jestřebí Castle area Abstract Rockfalls are one of essential causes of direct as well as indirect damages in residential areas. To mitigate negative impacts on society it is necessary to assess the risk posed by rockfall and choose suitable protective measures. Achievement of these targets needs a better understanding of the whole process of rockfall including natural conditions and trigger factors. Presented case study deals with rockfalls in the Jestřebí Castle area. The castle bedrock is formed by quartzose sandstones of the Cretaceous age. Stability of the masiff deteriorates in the last 200 years. The first rockfall was registered in the year 1811. Main cause is imputed to human interventions after 1400 AD when construction of the castle began, including the sandstone quarrying in 1750 - 1850 AD. As additional adverse conditions and factors were identified the weathering along conglomerate and bioturbated horizons resulted in a horizontal dissection of the sandstone outcrop and also a vertical separation along joints caused by nearby fault zone. The latest significant rockfall in October 1st 2009 wasted over 100 m3 of rocks from the western wall of the sandstone massif. Further rockfalls due to low stability of the massif can be expected in the near future. Keywords: rockfalls, slope...
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EVOLUTION OF ICEFALL IN LABSKÁ ROKLE RAVINE DURING 2014-2016
Švec, Matěj ; Engel, Zbyněk (advisor) ; Šťastná, Petra (referee)
The objective of this thesis is to characterize the Labská rokle creek icefall in terms of its morphology and types of ice structures. It describes the icefall's development during the winter season and analyses the impact of meteorological factors. The data about the icefall's volume were collected via sequential photographing and 3D scanner measuring during the winter seasons 2014/15 and 2015/16. The collected data were compared with the data from temperature sensors situated below the icefall and in its close proximity and with the data from the meteorological station in Labská bouda hut. The given icefall showed a very fast growth in the first phase of its development. This phase was followed by a typically stable phase of small fluctuations and subtle reactions to surrounding stimuli. In the third phase, a rapid decline in volume occurred as a result of either episodic events, such as when a larger piece of ice came loose, or progressive thawing. Regarding the factors, it was confirmed that temperature had the biggest impact on the volume of the icefall. A very high correlation was also found to be between the icefall's volume and the height of snow. A bigger snow height apparently puts off the stable phase and allows a greater accumulation of ice. The impact of global radiation and sunlight...
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Retreat of mountain glaciers from the Little Ice Age maxima in western Canada
Balkhausen, Maximilian ; Margold, Martin (advisor) ; Engel, Zbyněk (referee)
The Little Ice Age is a term describing a period of significant cooling compared to the long- term average of the current interglacial. During this period, there was a significant expansion of mountain glaciation worldwide. This study deals the retreat of mountains glaciers from the Little Ice Age maxima in western Canada. A total of 60 glaciers were mapped in three study areas in the mountains of northern British Columbia along the west-east climate transect. The study areas are located in the northern Coast Mountaisn, the northern Interior Mountains and the northern Canadian Rocky Mountains. The monitored glaciers were manually mapped using Landsat satellite imagery from 1977, 1987, 1997, 2007 a 2017. The glacier extent during the Little Ice Age maxima was mapped using PlanetScope satellite imagery with a resolution of 3 m, where it was possible to trace moraines from this maxima. The decline of the glacial area in the northern Coast Mountains from the Little Ice Age maxima to 2017 was 22,1 %, in the northern Interior Mountains 41,3 % and in the northern Canadian Rocky mountains 41,0 %. High variability was found for the relative glacier retreat among smaller glaciers in all study areas. This suggests that glacier response to climate change is not only conditioned by climatic factors, but also by...
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Remote Sensing of Surface Meltwater on the Glaciers of Svalbard
Sieglová, Eliška ; Margold, Martin (advisor) ; Engel, Zbyněk (referee)
Supraglacial lakes pond meltwater on the surface of glaciers. They form in the ablation zone during the ablation season and their darker surface lowers the albedo of the glacier. Once drained to the glacier bed, they may affect basal sliding and flow velocities of the glacier. High- resolution imagery from the Sentinel-2 mission was used to characterize the ablation season on two glacier regions of Svalbard: Hinlopenbreen glacier on the east coast and Kongsbreen and Kronebreen glaciers on the west coast of Spitsbergen. The first supraglacial lakes appeared in the first half of June in the west region and in the second half of June in the east region. The peak of the lake area was observed around the turn of June and July in the west region and around the half of July in the east region. The time of the first appearance of supraglacial lakes corresponded with temperatures reaching positive values. They first formed in lower elevations and started progressing higher with rising temperatures. Most supraglacial lakes formed between 600 and 700 m a.s.l. in the west region and between 400 and 500 m a.s.l. in the east region. In the east region a significant number of the supraglacial lakes (12 % of their total area) formed above the estimated equilibrium line altitude of 600 m a.s.l. Further research...
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Paleogeographic development of the Cenozoic river systems in the central and northern Bohemia and its link to climatic changes and neotectonics
Štor, Tomáš ; Martínek, Karel (advisor) ; Engel, Zbyněk (referee) ; Nichols, Gary (referee)
The main aim of this thesis is to provide greater details on the timing of the fluvial river systems formation in the middle and the northern Bohemia. We focused on the Ploučnice River and Vltava River evolution. The river systems are very complex therefore we have used multiple approaches of the research with the disciplines range from geology, sedimentology, geomorphology, geochemistry, over different dating methods such as 10Be and 26Al isochron burial dating, optically stimulated luminescence dating and radiocarbon dating methods. Our results suggests that the terraces are significantly older than previously proposed. The fluvial style of the Ploučnice River system changes from high-energy braided to long-bend meandered river in the upper terrace levels (36 to 29 m above the modern river) and from high- to medium-energy braided river in the middle terrace levels (22-14 m). In the lower terrace levels (13 to 5 m) high-energy braided to long-bend meandered river environments were identified. Terraces were dating at 34 m, 29 m and 14 m above the modern floodplain with cosmogenic radionuclides while the 19 m, 12 m and 6 m above the modern floodplain terraces were dating with OSL. The time span represented by the river terraces remains unclear and varies from Eburonian to Eemian (1.68 to 0.056 Ma)....
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Geomorphological conditions for debris-flows in the central part of the Western Tatras
Dlabáčková, Tereza ; Engel, Zbyněk (advisor) ; Vilímek, Vít (referee)
This thesis focuses on morphometric characteristic of debris flows and also areal and frequency changes over time in the Roháčská Valley and its tributary valleys, Western Tatra Mountains. Aerial images taken in 1973, 1986, 2003 and 2015 were used to delineate the spatial extent of debris flows transportation-accumulation zones as well as their length in each period. Changes within the whole period 1973 - 2015 were quantified and a general trend in debris flows spatial extent was outlined. Selected morphometric characteristic (e.g. elevation, slope, aspect or solar radiation) for both the initiation and deposition areas were determined for the present debris flow tracks using the digital elevation model. Field works were aimed to delineation of transportation-accumulation areas below the tree line (paticular attention was given to frontal parts and lateral léves of debris flow accumulations). The degree of weathering of selected boulders (Schmidt hammer test) was determined and also the diameter of Rhizocarpon geographicum thali was measured. About 98 debris flow tracks presently occur in the study area. In the periods of 1973 - 1986 and 2003 - 2015 decrease of debris flows transportation-depositional zones was observed, unlike the period of 1986 - 2003 when slight increase of debris flows...
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