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Emplacement and magnetic fabrics in dikes of syenite porphyries (Western Moldanubian Zone)
Orságová, Lucie ; Verner, Kryštof (advisor) ; Žák, Jiří (referee)
ENGLISH ABSTRACT We present new results of structural and magnetic (AMS) analyses of selected dikes of melasyenite, quartz melasyenite to melagranite porphyries accompanied by lamprophyres (minettes). The studied dike from the locality Nihošovice were dated by U-Pb method on zircons at 338 Ma. The asymmetric structural pattern of the studied dikes gives an excellent evidence for their emplacement and orientation of magmatic flow. The studied dikes were emplaced into: (i) Prevailing parts of the Central Bohemian Plutonic Complex (locality Malčice) and (ii) host high-grade metamorphic rocks of western part of the Moldanubian Zone (locality Nihošovice). Despite of the extensive area of occurrence, compositional variations and age of emplacement of these dikes are relatively narrow. Their geochemical and petrological compositions broadly correspond to ultrapotassic plutonic rocks (durbachites). The dikes are steeply dipping in trend ~NNW-SSE to ~W-E, with range in width between ~20 and ~25 meters. In general, our results show: (i) A relatively low degree of magnetic anisotropy (P= 1.012 - 1.152); (ii) Mostly oblate (planar) fabric, especially in marginal parts of the intrusive bodies (T= -0.091 - 0.941); (iii) Evidence for subhorizontal magmatic flow trajectory defined for a newtonian magma with typical...
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GEOMORPHOLOGY OF VELKÝ AND MALÝ BLANÍK
Bártová, Jitka ; Votýpka, Jan (advisor) ; Verner, Kryštof (referee)
Thie thesis consists of three main parts: an introduction, a description of physical conditions in the studied area and a main part which includes results of geomorphologic research and mapping. The area of interest is situated in central Bohemia in preserved area called Blanik. In the region there are two structural hills where the research was done. The names of these hills are Velký and Malý Blaník. Geologic structure of the region is built of Proterozoic - Paleozoic metamorphic rocks of Moldanubicum. Moldanubicum is represented here by muscovite - biotite orthogneiss (called blanicka ) and muscovite - biotite paragneiss. Both hills are created by muscovite - biotite orthogneiss so all the landforms are of its origin. There were classified structural, cryogenic, fluvial and other landforms in this thesis. Special attention was paid to cryogenic forms: frost - riven cliffs, cryoplanation plateaux, pseudocirques, block fields and many others. Almost 1000 measurements of joints were done. Cloose` s rosettes show systems of joints which prove tectonic system in the region and determine different mezoforms. Mapping brought some more results. Fluvial erosional and accumulative forms were classified as well as the anthropogenous forms. Powered by TCPDF (www.tcpdf.org)
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