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Biotites of the Třebíč pluton
René, Miloš
Biotite of the Třebíč pluton could be divided into four varieties with variable Fe/Mg ratios. Biotites of durbachites and basic enclaves are enriched of eastonite component, biotites of biotite- and garnet-biotite granites are enriched of siderophyllite component.
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Dynamics of Earth gases emissions in Czechia
Kroufek, J. ; Stejskal, M. ; Šebor, G. ; Mrlina, Jan ; Tesař, J. ; Suchý, V. ; Zeman, A.
A monitoring of the Earth gases emissions was carried out at selected sites in Cechia. Particularly, methan, CO2, SO2, Rn a H2S were investigated. It was proved that neither the chemical composition, nor the emissions themselves can be considered as permanent. They may be affected by geological processes including earthquakes, as well as by man-made activities.
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Staurolite-bearing rocks of the Hrubý Jeseník Mts
René, Miloš
Staurolite-bearing rocks accompany in the Hrubý Jeseník Mts. muscovite, muscovite-biotite micaschists and biotite gneisses in the Devonian envelope of the Desná Dome. Staurolitebearing rocks form variously thick lenses and irregular layers in the series of strata micaschists and gneisses.
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Evolution of topaz-bearing granites in the Krásno and Vysoký Kámen area (Slavkovský les Mts.)
René, Miloš ; Kempe, U. ; Wolf, D.
In the area between Krásno and Vysoký Kámen, southwestern of Karlovy Vary some stocks of topaz-albite granites are evolved, which are part of the Krudum granite massif. The Krudum massif has a markedly zoned internal structure with the oldest porphyritic biotite granites in its central part and younger two-mica granites and topaz-albite granites on its periphery. Topaz-bearing granites are evolved by means of progressive fractional crystallization from peraluminous granite melt.
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Cenozoické vulkanické série v západní části Českého masívu
Ulrych, Jaromír ; Novák, Jiří Karel ; Lloyd, F. E. ; Balogh, K. ; Hegner, E. ; Viereck-Götte, L. G.
The western part of the Ohře/Eger Rift is a geodynamically active area in the Alpine foreland. Associated Cenozoic alkaline volcanism, particularly that of Quaternary age, plays an important role in the seismic active region of the W Bohemia and Saxony and is accompanied by intensive manifestations of mantle degassing (CO2, He, N). Three Tertiary to Quaternary alkaline volcanic rock series were recognised there: 1. Early Oligocene to Early Miocene (31-20 Ma) in the Doupovské hory Mts. and western Ohře Riftu. 2. Middle to Late Miocene (16-8 Ma) associated with the Cheb-Domažlice Graben. 3. Pleistocene (0.43-0.26/0.11 Ma) associated with the Ohře Rift and Cheb-Domažlice Graben junction. On the basis of isotopic and geochemical data of the primitive mafic volcanics of all series the source of magmas is a sublithospheric HIMU mantle source.
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