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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Primární a sekundární magnetická stavba spraší jako nástroj pro rekonstrukci paleoprostředí / Primary and secondary magnetic fabric as a tool for paleoenvironmental reconstruction

Žatecká, Michaela January 2021 (has links)
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...
2

Rudistová společenstva svrchní křídy ve výplních kapes teplického ryolitu - systematika, paleoekologie, stratigrafie / Rudist assemblages of the Upper Cretaceous "pocket" infills in the Teplice rhyolite - systeamtics, palaeoecology, stratigraphy

Křížová, Barbora January 2018 (has links)
The study (MS, diploma thesis) is based on more than 1500 rudist samples from the Upper Cretaceous sediments of localities Písečný vrch and Na Stínadlech (near Teplice). Investigated samples come mainly from the collection of A. H. Fassel and were collected at the end of the 19th century, currently stored in the Regional museum in Teplice and National museum in Prague. The rudist shells were determined by generic and species levels, including five genera and eight species. The stratigraphic age of both localities has been a subject of discussion since the second half of the 19th century. In the recent decades, the opinion on the lower turonian age prevailed. However, five of the eight species present in the studied localities demonstrate the upper cenomanian age of the assemblages, making them probably the oldest known rudist-corals assemblages of its kind. The palaeoecological analysis and the ecological relationships proposal for the studied localities is based on the research in literature on palaeoecology and evolution of the rudists, also presented in the study. Key words: Bohemian Cretaceous Basin, Cenomanian - Turonian, rudists, corals, palaeoenvironment, Teplice rhyolite

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