Structural position of high-pressure felsic to intermediate granulites from NE Moldanubian domain (Bohemian Massif)

Autor(en)

Lucie Taj¿manová, I Soejono, J. Konopásek, Jan Kosler, Urs Kloetzli

Abstrakt

At the northeastern edge of the Moldanubian Zone, a large body of felsic to intermediate granulite with relics of high-pressure mineral assemblage is exposed within medium-grade paragneisses, micaschists and metagranites. A polyphase tectonic evolution in the study area resulted in three deformation phases (D1–D3). Peak metamorphic conditions (860–1000 °C and 16 kbar) in granulites are interpreted as reflecting an early stage of the high-grade evolution of the orogenic lower crust. These conditions were followed by exhumation of the orogenic lower crustal block to mid-crustal levels (6–8 kbar). In contrast to this, the study of metamorphic conditions in the surrounding micaschists (660 °C and 8 kbar) shows that these rocks never experienced pressures and temperatures of the orogenic lower crust. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb dating of zircon from the granulite yielded a concordia age of 354 ± 7 Ma, whereas the conventional isotope dilution thermal ionization mass spectrometry (ID-TIMS) and LA-ICP-MS dating of xenotime gave identical concordia ages of 336.2 ± 1.2 and 339 ± 3 Ma, respectively. Combination of new structural and petrological results with LA-ICP-MS zircon and xenotime dating leads to development of a well-constrained exhumation model and brings new insights into the behaviour of lower crustal rocks during orogenesis.

Organisation(en)

Department für Lithosphärenforschung

Externe Organisation(en)

Charles University Prague

Journal

Geological Society Special Publications

Band

167

Seiten

329-345

Anzahl der Seiten

17

ISSN

0305-8719

Publikationsdatum

2010

Peer-reviewed

Ja

ÖFOS 2012

1051 Geologie, Mineralogie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/4facde0e-d37a-4560-8669-f22863e2ac9c