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Moisture regime in near sub-surface of porous rocks: measurement and visualization
Weiss, Tomáš ; Bruthans, Jiří (advisor) ; Migoň, Piotr (referee) ; Kumar, Navneet (referee)
Moisture regime in near sub-surface of porous rocks: measurement and visualization Doctoral thesis Tomáš Weiss Charles University, Faculty of Science Abstract The near-subsurface of porous rocks plays a critical role in hydrological, physical, and chemical interactions between the atmosphere and the lithosphere. Hydrologically, the area can be conceptually divided into two zones: the dry surface layer and a deeper zone with capillary water, separated by the so-called evaporation front between the zones. Since salts tend to crystallize at the evaporation front, knowledge of its depth is important for understanding weathering processes. However, measuring the depth of the front is difficult, as differences in water content above and below the front are too low to measure by most methods. This thesis presents new methods for studying the evaporation front and tests them in a variety of lithologies and climates. Na-fluorescein dye was used for visualization of the front either as a direct application to the material in the form of solution or powder or as a part of a moisture probe on which the dye dissolves in the capillary zone. This moisture probe (named uranine- probe) was successfully tested and used in a range of porous rock types, from sandstone and limestone to rhyolite, building materials, and soil;...
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