|
|
Differentiation and crystallization of evolved granitic melts, the Říčany pluton, central Bohemian Massif
Jandová, Tereza ; Dolejš, David (advisor) ; René, Miloš (referee)
Evolved silicic rocks display a variety of igneous textures, which can provide important information on crystallization kinetics and rheology in natural magma chambers. Individual kinetic effects such as diffusion rate, nucleation rate, growth rate and post-solidification modifications are likely to be reflected in the modal and textural appearance of the resulting rock. This work focuses on characterization and interpretation of solidification textures in a 600 m wide and 5 km long body of highly evolved, boron-rich aplites and pegmatites at the southern endocontact of the Říčany granite pluton (Central Bohemian Plutonic Complex). This rock suite is associated with biotite Říčany granite, hosting microgranite and aplite dyke swarm, and it is built up by massive tourmaline aplites, layered aplites with tourmaline-rich or locally garnet-rich bands, pegmatite pockets, pegmatite layers with unidirectional solidification textures (comb layers), megacryst zones (analogous to stockscheider), and late pegmatite dykes discordant to layering. Textural as well as modal variations are usually sharp and observable megascopically as well as on the microscale. All aplites and pegmatites usually contain similar proportions of quartz, albite-rich plagioclase, K-feldspar, various proportions of tourmaline (up to...
|
|
|
Differentiation and crystallization of evolved granitic melts, the Říčany pluton, central Bohemian Massif
Jandová, Tereza ; Dolejš, David (advisor) ; René, Miloš (referee)
Evolved silicic rocks display a variety of igneous textures, which can provide important information on crystallization kinetics and rheology in natural magma chambers. Individual kinetic effects such as diffusion rate, nucleation rate, growth rate and post-solidification modifications are likely to be reflected in the modal and textural appearance of the resulting rock. This work focuses on characterization and interpretation of solidification textures in a 600 m wide and 5 km long body of highly evolved, boron-rich aplites and pegmatites at the southern endocontact of the Říčany granite pluton (Central Bohemian Plutonic Complex). This rock suite is associated with biotite Říčany granite, hosting microgranite and aplite dyke swarm, and it is built up by massive tourmaline aplites, layered aplites with tourmaline-rich or locally garnet-rich bands, pegmatite pockets, pegmatite layers with unidirectional solidification textures (comb layers), megacryst zones (analogous to stockscheider), and late pegmatite dykes discordant to layering. Textural as well as modal variations are usually sharp and observable megascopically as well as on the microscale. All aplites and pegmatites usually contain similar proportions of quartz, albite-rich plagioclase, K-feldspar, various proportions of tourmaline (up to...
|
|
| |
|
|
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.
|
|
| |
|
| |
|
| |
|
| |
|
|
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.
|
|
| |
guest ::
