This Masetr thesis looks into weathering pits of nature park Česká Kanada. The theoretical part of the thesis investigates research of weathering pits done in the Czech Republic as well as abroad. The practical part deals with weathering pit-bearing as well as weathering pitabsent blocks of rock within the study area. It describes their geological-geomorphological environment and attempts to find differences between the weathering pit-bearing and absent blocks (the presence of cracks, altitude, landforms, shape of the rock block and more). Furthermore it was established that a suitable rock block morphology (respectively the existence of horizontal plane) is important for formation of weathering pits. It also studies water properties in selected weathering pits, relationship of overhangs to prevailing wind directions. A correlation between overhang and wind direction was found in sense that NW to W winds correspond with overhang formation on eastern sides of weathering pits. Water in weathering pit of Čertův kámen located in sunny bare landscape shows significantly different properties in comparison with water properties of remaining weathering pits located in forrested areas.

abstract: Gnamma pit is an Australian aboriginal term for weathering pit. A mix of weathering and aeolian processes controls the formation of gnamma pits. There is a potential to utilize gnamma as an indicator of paleowind intensity because gnamma growth is promoted by the removal of particles from gnamma pits by wind, a process referred to as deflation. Wind tunnel tests determining the wind velocity threshold of deflation over a range of pit dimensions and particles sizes are conducted. Computational fluid dynamics (CFD) modeling utilizing the Re-Normalisation Group (RNG) K-Epsilon turbulence closure is used to investigate the distribution of wall shear stress and turbulent kinetic energy. An empirical equation is proposed to estimate shear stress as a function of the wind velocity and pit depth dimensions. With this equation and Shields Diagram, the wind velocity threshold for evacuating particles in the pit can be estimated by measuring the pit depth ratio and particle size. It is expected that the pit would continue to grow until this threshold is reached. The wind speed deflation threshold is smaller in the wind tunnel than predicted by the CFD and Shields diagram model. This discrepancy may be explained by the large turbulent kinetic energy in the gnamma pit as predicted by the CFD model as compared to the flat bed experiments used to define the Shields diagram. An empirical regression equation of the wind tunnel data is developed to estimate paleowind maximums. / Dissertation/Thesis / Masters Thesis Geography 2015