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Emplacement and fabric patterns of plutons in the eastern periphery of the Moldanubian Zone; implications for geodynamic evolution of the Bohemian Massif
Vondrovic, Lukáš ; Verner, Kryštof (advisor) ; Melichar, Rostislav (referee) ; Johnson, Kenneth (referee)
The Ph.D. thesis focuses on an analysis of the structural record and geochronology of selected calc-alkaline plutons emplaced in the rocks of the eastern periphery of the Moldanubian Zone (eastern margin of the Bohemian Massif). In addition, it includes an analysis of the tectonic and metamorphic record of the host rocks of the Polička and Zábřeh Units. The results revealed a number of important implications regarding the geodynamic evolution of the north- eastern part of the Bohemian Massif. The rocks of the Zábřeh Unit were metamorphosed under middle temperature and lower pressure conditions (T: 660 C, P: 0.6 Gpa). The structural record is defined by the superposition of regional steep E-W trending metamorphic fabric (S1) which was variably obliterated by means of intensive folding into S2 flat-lying foliation. This unit is in the northern part intruded by calc-alkaline rocks of the Zábřeh Intrusive Complex (354±4Ma, U/Pb on zircons) with calculated P-T crystallisation conditions of 706-795 řC and P: 0.3-0.4 Gpa. A contact metamorphic event took place within the host rocks in the proximity of the intrusion (T: 599-663 C, P: 0.4 Gpa). The internal fabric of the Zábřeh Intrusive Complex exhibits a magmatic to submagmatic gradient and the orientation of the intrusive contacts and magmatic...
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Petrology of differentiated alkaline, high-level intrusive bodies in the Zahořany - Chotiněves belt
Mysliveček, Jakub ; Verner, Kryštof (advisor) ; Erban, Vojtěch (referee)
The aim of the work was petrological research focused on alkaline volcanic bodies in line between villages Zahořany - Chotiněves near Litoměřice. Part of the area is covered by Tertiary volcanism products, which affected large parts of Europe and in our territory extends in the form of extensional structure of Ohře rift. The Field of studied objects is located nearby the southern edge of České středohoří vulcanic complex and the northern edge of the Central Volcanic Field. The question was whether studied area belongs, if it's still České středohoří volcanic complex or it belongs to Central Bohemian volcanic field. The area was visited several times for determinate the volcanic bodies and have been identified six localities which were collected rock samples for geochemical analysis and Probe Micro Analysis. Also, the detailed mapping of the bodies and their spatial extensions was performed because currently available geological map of 1: 50 000 do not correspond to reality. The area is situated close to Litoměřice break, which probably caused the linear distribution of magma in the direction of fracture, approximately NE - SW. Studied rocks by the classification TAS are classified as basaltic trachyandesites and are mainly composed by plagioclase, clinopyroxene, magnetite and to a small extent from biotite...
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Structural evolution of the Královský Hvozd Unit
Vrtiška, Luboš ; Verner, Kryštof (advisor) ; Žák, Jiří (referee)
5 English abstract The introduction of the thesis represents a profound research of current knowledge and survey results to date about the geodynamic tectonic boundary development of the Teplá- Barrandien unit/Moldanubian senzu stricto and the Královský Hvozd unit in the Šumava Mountains. It also describes in detail lithology of the Královský Hvozd unit and historical as well as contemporary opinions of the tectonometamorphic development of the Královský Hvozd unit and adjacent Moldanubian unit and Teplá-Barrandien unit. The research part of the thesis brings results of the analysis of the Královský Hvozd unit tectonic development in relation with the tectonic development of broader surrounding area. The research combines field structural data, detailed microstructure data acquired from collected samples and results of studying deformation mechanisms on orthogneiss samples from the Královský Hvozd unit using the EBSD (Electron Back Scattered Diffraction) performed on partly recrystalised quartz aggregates. The research output is a construction of a tectonic development model of the Královský Hvozd unit and the adjacent area. Four main deformation events (D1-D4) were determined on the basis of structural record and their time sequence in the rocks of the Královský Hvozd unit. On the basis of kinematic...
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Fabrics and geodynamic evolution of orthogneisses in the Moldanubian Zone
Kryl, Jakub ; Verner, Kryštof (advisor) ; Venera, Zdeněk (referee)
Fabrics and geodynamic evolution of Moldanubian orthogneisses English abstract The aim of this paper is a structural analysis of selected mostly Cambro-Ordovician orthogneisses cropping out in a part of high-grade rocks of western Moldanubian Zone. These rocks have been affected by HT-MP/LP metamorphism and the polyphase deformation during the Variscan orogeny. In the blaník orthogneisses, (Qtz + Kfs + Plg + Bt ± Ms ± Sill ± Ky) an early deformation banding dips steeply to SSE to ESE. These fabrics were overprinted by NW to N gently dipping foliation with well developed stretching lineations plunging to W. Rare kinematic indicators (e. g. fold and pressure shadows asymmetry) reveal a strong subvertical contraction and stretching in the ~N-S direction. Based on the microstructural analysis this contractional event was connected with the activity of "Grain Boundary Migration Recrystallization" (GBM). Ductile shear zones dipping to E, locally ESE or ENE were identified. Bechyně orthogneisses (Qtz + Kfs + Plg + Bt ± Ms) is a N-S elongated body with the presence of regional pervasive metamorphic foliation dipping homogenously under low angles from SSW to WNW . These foliations bear well developed mineral or stretching lineation of quartz, biotite and feldspar aggregates plunging to ~SW. In the blaník orthogneiss...
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Fabrics and emplacement of Weinsberg - type granitoids (Moldanubian Batholith)
Pour, Ondřej ; Verner, Kryštof (advisor) ; Buriánek, David (referee)
English abstract This diploma thesis is concerned with the brief introduction to the structures and fabrics in granitoid plutons. In the next part of this work are sumarized results of structural analyses of Weinsberg-type granite intrusion (Prášily and Strážný pluton) located in the SW part of high-grade rocks of the Moldanubian Zone. This research proceeded based on a combination of field structural data and results of AMS (Anisotropy of magnetic susceptibility) method. The emplacement and crystallization of both studied magmatic bodies took place in cooperation with the final phases of S3-fabrics development. This "bavarian phase" has a character of heterogenous deformation with indications of the dextral subhorizontal shear (WNW-ESE strike). During this event, syntectonic emplacement and internal fabrics development of strážný pluton took place at ~322 Ma. The transpression was followed by the localized transtension tectonics in NE direction, probably in cooperation with exhumation of high-grade metamorphic rocks of Bavarian terrane. In this phase, at ~320 Ma, the granitoids of Prášily pluton were emplaced into the considerably exhumed crust of the Moldanubian region.
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Geodynamic evolution and emplacement of Eisgarn - type granitoids (Moldanubian Batholith)
Paclíková, Jana ; Verner, Kryštof (advisor) ; Franěk, Jan (referee)
English abstract This diploma thesis deals mainly with identification of magmatic (respectively magnetic) fabrics, geodynamical aspects of emplacement and geochronology of the Eisgarn granitoids. For the analysis Klenov and Mrákotín pluton were chosen, which is placed in the eastern part of the Moldanubian Batholith. This thesis contains petrological and mezoscopic structural analysis of the host metamorphic rocks of the Moldanubian Unit and it includes calculation of P-T conditions of the main mineral assemblage. This is followed by petrological, geochemical and mezoscopic structural analysis of the Klenov and Mrákotín pluton and analysis of the anisotropy of magnetic susceptibility, geochronology of the Klenov pluton, gravimetry analysis and determination of the orientation of density interfaces in different depths. Granitoids of the Klenov and Mrákotín pluton are characterized as S-type granitoids, whose protolith were probably metasedimentary rocks. From the analysis it is also evident that the Klenov pluton records lower degree of magma fractionation than the Mrákotín pluton. The emplacement and crystallization of both studied magmatic bodies took place in cooperation with a development of regional metamorphic fabrics, which originate between 329 and 327 Ma. During this period a rapid exhumation of...
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Magnetic fabrics and emplacement of the Eisgarn granitoids (Moldanubian Plutonic Complex)
Paclíková, Jana ; Verner, Kryštof (advisor) ; Buriánek, David (referee)
English abstract We consider our preliminary results of structural and AMS analyses of granitoids of the Mrákotín and Klenov Plutons located in the northeastern part of the Moldanubian Plutonic Complex. Both plutons have a peraluminous, high-K character formed by partial melting of a crustal metasedimentary (metapelite) source at relatively lower temperatures. The Mrákotín pluton (eastern part of the plutonic complex) was emplaced posttectonically at around 327 Ma and records a crucial role of magmatic stoping during magma ascent and emplacement. In contrast, the Klenov pluton (western part of the plutonic complex) was emplaced syntectonically with regional HT-LP tectonometamorphic event (formation of gently to moderately NNE dipping metamorphic schistosity).
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Fabrics of the Weinsberg granitoids on example of the Prášily pluton (Moldanubický plutonický komplex)
Pour, Ondřej ; Verner, Kryštof (advisor) ; Racek, Martin (referee)
This bachelor thesis is concerned with the brief introduction to the structures and fabrics in granitoid plutons. In the next part of this work are sumarized results of structural analyses of Weinsberg-type granite intrusion (Prášily pluton) located in the SW part of high-grade rocks of the Moldanubian Zone. This research proceeded based on a combination of field structural data and results of AMS (Anisotropy of magnetic susceptibility) method. The internal fabrics and structures of the Prášily pluton reflect emplacement mechanisms, kinematic history and evolution of the regional strain field during Variscan orogeny at around 330 Ma. The examined area provides crucial constraints for the geodynamic models of geological evolution of deeper parts of the Variscan orogen in the SW part of the Bohemian Massif.
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