National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Primary and secondary magnetic fabric as a tool for paleoenvironmental reconstruction
Žatecká, Michaela ; Chadima, Martin (advisor) ; Pruner, Petr (referee)
This diploma thesis deals with the research of primary and secondary magnetic fabric of aeolian loess sediments and paleosols on the cross-section temporary cropping out during the construction work in Prague 6. Magnetic enrichment - and the formation of magnetic nanoparticles in soil horizons - occurs during pedogenesis in warmer interglacials periods. The aim of this work is the interpretation of the paleoenvironment, weathering and pedogenic processes, by measuring the magnetic properties of sediments. Magnetic susceptibility, frequency-dependent magnetic susceptibility, anhysteresis remanent magnetization and natural remanent magnetization are used to detect the increased occurrence of magnetic particles, which indicate these pedogenic processes. The most developed paleosol horizon within the cross-section was the horizon of black soil and subsoil brown soil. Small signs of pedogenesis were revealed in the upper and lower loess part of the section. The magnetic fabric of loess, measured by means of anisotropy of magnetic susceptibility, reflects secondary sedimentary processes. This involves the displacement of clastic particles by flowing water and the redeposition of the material along the slope. The direction of movement of these sediments corresponds to the current geomorphology of the...
Application of environmental magnetic techniques in Quaternary sediment study
Žatecká, Michaela ; Kadlec, Jaroslav (advisor) ; Kletetschka, Günther (referee)
5 ABSTRACT: The Bachelor Thesis presents basic principles of the environmental magnetic methods and their applications in paleoenvironmental reconstructions from Quaternary sedimentary archives. Description of mineral and rock magnetic principles follows after an introductory sketch of historical development of the environmental magnetic topic. Next part of the thesis is focused on explanation of basic principles of the environmental magnetic methods and application magnetic history of the sedimentary rocks: namely different kinds of magnetic susceptibility, anisotropy of magnetic susceptibility, remanent magnetization and hysteretic parameters of the sediments. Application of the environmental magnetic methods enables interpretation of depositional and/or post- depositional history (e.g., directions of wind or water currents transporting clastic sediments) or intensity of geochemical weathering (connected with pedogenesis) which is directly controlled by climatic conditions and their changes. Examples of application of the environmental magnetic methods in paleoenvironmental research of the deep ocean, lacustrine and eolian natural archives are described in the final part of the thesis. Key words: environmental magnetism, paleoenvironmental reconstruction, sedimentary archives, Quaternary

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