CLR person interests, research and publications
Researcher

Research interests
- Geodynamics and tectonics of accretionary and collisional orogenic systems
- Microstructural processes in rocks
- Crustal flow and exhumation of orogenic lower crust
Current research topics
My present research studies include: Geodynamic evolution of Central Asian Orogenic Belt in Mongolia and China involving accretion of oceanic lithosphere to continental nuclei and processes of cratonisation of accretionary wedges. My second main interest if focussed on understanding mechanisms of lower crustal flow and exhumation of HP rocks in the Variscan belt in Europe and north Africa. This topic also includes the relamination mechanisms: i.e. attachment of allochthonous lower plate crust to the autochthonous upper plate. My research of rheology of continental crust is mainly focussed on micro-mechanisms related to deformation at very high temperatures and/or high pressures exemplified by granulites and eclogites of the Bohemian Massif, Pyrenees, Madagascar and Mongolian Altai. I am also interested on role of magma and melt in orogens, mainly by examining fabrics and structures related to magma emplacement in both compressional and extensional tectonic settings. All that I am doing in collaboration with numerical and analogue modellers, geophysicists, geochemists and petrologists.
Curriculum
For large part of my scientific carrier I have worked in the domain of structural geology and tectonics of Paleozoic belts of the Central Europe, Proterozoic belts in Madagascar and Finland, West Carpathians and recently also Central Asia. I started my carrier as a head of the Structural Geology Laboratory of the Czech Geological Survey, in Prague. In 2001 I have been appointed chairman of the Institute of Petrology and Structural Geology (IPGS). In 2004 I was invited to Strasbourg with the goal to develop a geology pole in the Strasbourg University and since January 2009 I chaired the Dynamics of Lithosphere and Sedimentary Basins Group of the Institute de Physique du Globe de Strasbourg. From 2012 I am directing a Centre of Lithospheric Research at Czech Geological Survey.
In collaboration with Alan B. Thompson (ETH Zurich) we developed a new concept of exhumation of hot lower crust and with John W. Cosgrove (Imperial College, London) we worked on some mechanical aspects of deformation of anisotropic high-grade crustal rocks. With František Hrouda and Josef Ježek (Charles University, Prague) and Scott Paterson (University of South California) we addressed problems of magma flow and development of magmatic fabrics. In Strasbourg I developed strong collaboration with Jean Bernard Edel in the domain of paleogeography of European Variscan belt and with Jean Marc Lardeaux (University, Nice) we worked on general understanding this orogenic system. Recently I am collaborating with Stephane Guillot (University of Grenoble) on comparison of European Variscides with Tibet and with my Chinese colleagues (Min Sun, Hong Kong) on the crustal growth processes in Asia.
Research projects
The growth of eastern Pangea involves three contrasting orogenic cycles: 1) Baikalian cycle (570-540 Ma) consists of accretion of peri-Rodinian continental, Mirovoi and Panthalassan oceanic fragments to the Siberian margin followed by extensional HT reworking, the growth of magmatic arc, giant accretionary wedge and intraoceanic basin. 2) Altai cycle is typified by crustal thickening followed by syn-extensional melting of the accretionary wedge (420-380 Ma) and the opening of Mongol-Okhotsk ocean.
The granulite-gneiss extrusions in the Bohemian Massif are interpreted as parts of the lower plate, subducted, relaminated below the upper plate and exhumed as kilometre-scale translithospheric diapirs through upper plate. Because dominated by metagranites, it is repeatedly stated that they originated from continent subduction. Many studies were dedicated to their tectono-metamorphic Variscan evolution. Almost missing are studies trying to understand their paleo-environment that allowed such unprecedented travel of rocks through mantle.
Melt migration is the key process transferring mass, heat and volatiles from the Earth’s depth towards the surface, and therefore shaping the chemical and thermal structure of the lithosphere. Common understanding of crustal melt migration is biased towards mechanisms that can be easily identified as they preserve macroscopic segregations of melt in outcrops, such as in dykes or leucosome-bearing migmatites. In contrast, recent observations show that micro-scale pervasive flow of melt along grain boundaries can affect significant portions of hot continental crust.
Melting of the crust leads to granitic magmas that vary widely in composition and in ability to generate metal deposits or cause explosive volcanism. A number of superposing, competing processes control this variability. Much has been learnt from investigating processes late in the magma history, but not much is known about magma generation at depth and what happens to it during transport to the upper crust. Indirect knowledge or inferences based on little data, leads to speculation and controversies.
Selected segments of Euroasian orogenic system are used to constrain relative contribution of contrasting processes of continental construction in collisional and accretionary orogenic systems. Principal objectives of the proposal are: (i) identification of the individual terranes, kinematic analysis of their movements and characterization of deformation style connected with their amalgamation; (ii) estimation of net crustal growth vs. recycling of preexistent crustal material.
On the modern Earth, continental crust is created mainly at subduction zones. Here, release of aqueous fluid from dehydrating oceanic crust causes melting in the mantle wedge and generates the calc-alkaline magmas that evolve into granitoid continental crust. This project aims to understand crustal growth and possible crustal construction mechanisms, using the Mongolian and Chinese tract of the Central Asian Orogenic Belt (CAOB) as an example. The main questions raised here are: What were the cause, rate and timing of continental growth in the CAOB?