Reza Syahputra: Mechanisms and time scales of formation and accretion of ribbon continents
The Ph.D. project elaborates on the concept of ribbon terranes, narrow linear belts composed of juvenile or recycled crust that form by lithospheric extension of continental margins. The ribbon continents are of prime paleogeographic and plate-tectonic importance, now being increasingly recognized to play a crucial role in closure of oceanic domains, continental assemblies, growth of continental crust, large-magnitude strike-slip terrane displacements, and the development of oroclines. In its present stage, the Ph.D. research concentrates on formation and rift–drift transition of ribbon microplates using Cambrian sedimentary basins in the Bohemian Massif as a case example.
Funded by the Charles University Grant Agency project No. 952220 to Reza Syahputra.
Irena Olšanská: Late Variscan volcano-plutonic complexes as markers of evolution of post-orogenic tectonic processes
This Ph.D. project is focused on magmatic and tectonic processes associated with the late Variscan post-orogenic processes. Main methods are field mapping, structural, and geochronological analysis of selected volcano-plutonic complex, complemented by analysis of the anisotropy of magnetic susceptibility (AMS). Three case studies of interest are located in the NW part of the Bohemian Massif (Saxothuringian unit), in particular the Tharandt Wald caldera, Altenberg-Teplice caldera and Smrčiny/Fichtelgebirge batholith. The goal of this project is to interpret the late Variscan processes in these complexes, decipher their internal anatomy, and investigate interplay between dextral strike slip tectonics and dynamics of emplacement.
Funded by the Charles University Grant Agency project No. 124320 to Irena Olšanská.
Petr Vitouš: Influence of regional tectonics on dike swarms evolution beneath volcanics complexes
The Ph.D. project will focus on study of the internal architecture of feeding structures of volcanic complexes. Specifically, the project aims to investigate the area of the Eger Rift and the Altenberg-Teplice Caldera. The research will mainly include the structural study of dike swarms, sills, cone sheets and radial dikes. A combination of several methods will be used on selected volcanic complexes: detailed field and structural mapping, backscattered electron diffraction analysis (EBSD), rock magnetism, anisotropy of magnetic susceptibility (AMS) and anhysteretic remanent magnetization (AARM). This doctoral project aims to introduce a modern interpretations, a general geological model of the influence of extensional regional tectonics on the geometry of feeding structures of volcanic complexes. Last but not least, a comparative study of structure of basaltic to intermediate alkaline complexes of rift regions and felsic caldera volcanoes in collapsing orogens will be compiled.
Funded by the Charles University Grant Agency project No. 354821 to Petr Vitouš.
Jonah Jonathan: Thermal and mechanical interactions of dikes and hydrothermal fluids during collisional orogeny
Magma and and hydrothermal fluids percolate through the upper crust during all stages of collisional orogeny, from early closure of oceanic basins to late stage orogenic collapse, and are often closely spatially and temporally related, though occurring on different length scales. Except the well-known close genetic relationship between voluminous granitoid plutons and associated hydrothermal systems, the role of small-volume dikes, and especially of regional dike swarms, in facilitating hydrothermal fluid flow remains poorly known. The main issue is how and to what extent dikes and hydrothermal fluid pathways interact during the various phases of orogeny: (1) Do they represent completely separate events that just coincide in time and space? (2) Do they interact thermally, i.e., is magma transported through dikes able to trigger significant hydrothermal activity in the host rock? (3) Are the magma and fluid flows separate processes at deeper mantle/crustal levels to become coupled in the upper crust, driven by a single tectonic stress field and inherited basement structures? (4) Or are these processes entirely linked from their origin up to the final emplacement level? The project will address these and other related issues through analysis of several case examples in the Bohemian Massif, with a possible extension to other orogenic belt(s). The key initial example to be examined will be the Central Bohemian Plutonic Complex, where a prominent, regional dike swarms composed of numerous NW–SE and E–W dikes intrude into granitic plutons and their host rock, which, in turn, are cross-cut by abundant hydrothermal veins, in places making up large ore deposits.
Funded by the Charles University Grant Agency project No. 304721 to Jonah Jonathan
Tatiana Tkáčiková: Analog modeling of subduction zone processes
A wide range of complex depositional, deformational, and metamorphic processes that operate along subduction zones may be experimentally reproduced under laboratory conditions. The Bachelor research is focused on a critical evaluation of the existing experimental approaches and material parameters used to model subduction zone processes and evolution of accretionary wedges. Several pilot experiments will also be designed and interpreted in terms of geological processes during the second part of the project.