The concept of the superstructure and infrastructure definition is based on the differences in structural style and metamorphism between the upper, weakly metamorphosed and lower, mostly migmatitic crustal levels in orogenic core zones. According to these classic tectonic models, the orogenic infrastructure exhibits gently inclined and highly transposed fabrics while the orogenic superstructure shows upright folds and mostly vertical fabrics. The infrastructure – superstructure transition zone (ISTRA) has never been precisely defined and not specifically studied in orogens so far. Teplá crystalline complex is one of the few locations where the fossil ISTRA of Variscan orogenic crust could be studied. As the process of the transposition of steep fabrics to shallow dipping ones has polyphase character and the two orogenic events have been recognized in the area (Cadomian and Variscan), interpretation of structural and metamorphic evolution has been a matter of controversy for last decades. The aim of project to summarize existing and newly obtained field-structural, microstructural and petrological data, critically question the commonly accepted theory of “brittle-ductile transition” and formulate more general criteria to understand mechanical decoupling of orogenic crust.
Preliminary scope of work in English
The concept of the superstructure and infrastructure definition is based on the differences in structural style and metamorphism between the upper, weakly metamorphosed and lower, mostly migmatitic crustal levels in orogenic core zones. According to these classic tectonic models, the orogenic infrastructure exhibits gently inclined and highly transposed fabrics while the orogenic superstructure shows upright folds and mostly vertical fabrics. The infrastructure – superstructure transition zone (ISTRA) has never been precisely defined and not specifically studied in orogens so far. Teplá crystalline complex is one of the few locations where the fossil ISTRA of Variscan orogenic crust could be studied. As the process of the transposition of steep fabrics to shallow dipping ones has polyphase character and the two orogenic events have been recognized in the area (Cadomian and Variscan), interpretation of structural and metamorphic evolution has been a matter of controversy for last decades. The aim of project to summarize existing and newly obtained field-structural, microstructural and petrological data, critically question the commonly accepted theory of “brittle-ductile transition” and formulate more general criteria to understand mechanical decoupling of orogenic crust.