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Diploma thesis deals with geological, petrological, structural and geochemical studies of the most probably neoproterozoic volcanic and sedimentary rocks of the Pičín belt in the area NW from Dobříš, approximately between the villages Trnová and Chouzavá. Volcanics of Kozí hory area, which are demonstrably included into Davle Formation have beeen used for comparison with the Dobříš area. One of the major part of the work includes geological mapping on scale of 1:10 000, which served as a base for a more detailed petrological, structural and geochemical studies. Some lenses of lava and volcanoclastic breccia and minor layer spilite were newly discovered, areal extent of some cherts bodies and basaltic dykes were modified. Basalts, andesites and dacites bodies have been reclassified against the basic geological map of 1:25 000 (Havlíček, 1985; Mašek, 1987). Basalts in the Havlíček's (1985) map actually represent a very fine-grained rhyolites (ignimbrites) with disseminated ore minerals with layers of pyroclastic rocks (ignimbrites, volcanoclastic breccia). Areal extent of andesites and dacites bodies were modified and new body of trachyandesite was detected. Extremely fast cooled grained textures and series of features corresponding to welded tuff (ignimbrites) shows that the tuffs were deposited in... |
