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Magmatic and Volcanic Evolution of the Doupovské hory Volcanic Complex
Rapprich, Vladislav ; Holub, František (advisor) ; van Wyk de Vries, Benjamin (referee) ; Renno, Axel D. (referee)
The Doupovské hory Volcanic Complex (DHVC) occupies the western part of the northeast- southwest trending Eger Graben in northwestern part of the Bohemian Massif. The Graben follows the older Variscan suture between the Saxothuringian and Teplá-Barrandian Domains. The rocks of the DHVC are alkaline with setting and composition similar to other Cenozoic intraplate volcanic complexes of the Central and Western Europe (CIMACi). The Doupovské hory Volcanic Complex started the activity in the Lowermost Oligocene and lasted until Lower Miocene. The volcanic activity resulting in accumulation of the Doupovské hory Volcanic Complex was several times interrupted by periods of volcanic edifice decay and sector collapses. The magmatic activity lasted for ca. 14 M.y. and built a volcanic complex of total thickness 600-1000 m. The earliest volcanic activity was explosive in style and the eruptions could be classified as Strombolian to Sub-plinian and phreatomagmatic. The eruptions deposited about 80 m of volcaniclastics. This initial activity was dated by paleontology to the Lowermost Oligocene. The volcanic activity subsequently became calmer and lava flows dominated over explosive events. The growth of the early DHVC edifice culminated with intrusions of the Flurbühl intrusive complex by about 30-29 Ma. The...
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Volcanism of Large Igneous Provinces in Earth's history; possible impacts on global ecosystem
Zajícová, Jana ; Holub, František (advisor) ; Rapprich, Vladislav (referee)
Large igneous provinces (LIPs) are huge accumulations of magmatic rocks originated during unusually short time and characterized by extremely high magma productivity. Among them, namely the continental flood basalts (traps) cover very extensive areas and may or may not be associated to rifting and breakup of continents. However, also highly voluminous oceanic plateaus were recognized and some authors count to LIPs even some other types of huge magmatic complexes. A large amount of gases is released with escaping magma, usually oxides of carbon, sulfur and nitrogen. These gases more or less have impact on the environment and thus also influence organisms. The formation of magmatic provinces repeated many times in the past. The best known are continental Deccan Traps in India and the most voluminous Siberian Traps. Oceanic LIPs are represented, e.g., by the Ontong Java Plateau in the west Pacific Ocean. There is a link in dating the emergence of large igneous provinces and mass extinctions. As an example, the largest known extinction at the end of Permian, which was broadly contemporaneous with the formation of the Siberian traps (approximately 250 Ma ago), or extensive loss of species on the boundary of Cretaceous / Tertiary, which coincides with the formation of the Dekkan in India (before about 65...
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Magmatic and Volcanic Evolution of the Doupovské hory Volcanic Complex
Rapprich, Vladislav ; Holub, František (advisor) ; van Wyk de Vries, Benjamin (referee) ; Renno, Axel D. (referee)
The Doupovské hory Volcanic Complex (DHVC) occupies the western part of the northeast- southwest trending Eger Graben in northwestern part of the Bohemian Massif. The Graben follows the older Variscan suture between the Saxothuringian and Teplá-Barrandian Domains. The rocks of the DHVC are alkaline with setting and composition similar to other Cenozoic intraplate volcanic complexes of the Central and Western Europe (CIMACi). The Doupovské hory Volcanic Complex started the activity in the Lowermost Oligocene and lasted until Lower Miocene. The volcanic activity resulting in accumulation of the Doupovské hory Volcanic Complex was several times interrupted by periods of volcanic edifice decay and sector collapses. The magmatic activity lasted for ca. 14 M.y. and built a volcanic complex of total thickness 600-1000 m. The earliest volcanic activity was explosive in style and the eruptions could be classified as Strombolian to Sub-plinian and phreatomagmatic. The eruptions deposited about 80 m of volcaniclastics. This initial activity was dated by paleontology to the Lowermost Oligocene. The volcanic activity subsequently became calmer and lava flows dominated over explosive events. The growth of the early DHVC edifice culminated with intrusions of the Flurbühl intrusive complex by about 30-29 Ma. The...
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Variscan igneous activity at the Bohemicum/moldanubicum boundary
Kubínová, Šárka ; Holub, František (advisor) ; Pertoldová, Jaroslava (referee)
Variscan dike swarms associated with the Central Bohemian Plutonic Complex (CBPC) at the boundary between the Teplá-Barrandian and Moldanubian Units of the Bohemian Massif represent one of the most interesting geological phenomena. Frequency of dykes and their chemical variability do not have any comparable analogy in the whole European Variscides. This work is focused on the study of dyke rocks in the NE periphery of CBPC in geologically very complicated area with intrusions of predominantly deformed granitoids, contact metamorphosed sediments and magmatic rocks of "Islet Zone" with different protolith ages (forming remnants of the original roof of CBPC), deformed basic rocks of uncertain origin and age. The area extends up to the western boundary of the northernmost part of the Moldanubian high-grade metamorphic complex, the boundary itself being also tectonically problematic. Several localities with dyke rocks under study are situated in the area east of Senohraby (SE of Prague), on the northern side (right coast) of the Sázava river, and extend up to the area of Stříbrná Skalice. This area is rich in dykes of gabbro to diorite porphyry accompanied in some places with tonalite (rarely quartz diorite) porphyry and more rarely with amphibole lamprophyres (spessartite). Significantly younger dykes...
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