Petrochronological study of chloritoid schist from Medvednica Mountain (Zagorje Mid-Transdanubian zone, Croatia)

Author(s)
Ivan Mišur, Dražen Balen, Urs Klötzli, Mirko Belak, Hans Joachim Massonne, Mihovil Brlek, Vlatko Brčić
Abstract

The metamorphic conditions and evolution of the Palaeozoic-Mesozoic metamorphic complex of Medvednica Mountain (Zagorje-Mid-Transdanubian zone, Croatia) are still a matter of debate. The results of the investigation of five samples of metapelitic schists with the mineral association of quartz, white mica and chlorite are presented. The studied schists are part of the continental margin of Adria and were metamorphosed under upper greenschist-to amphibolite-facies conditions. The focus of this study is a sample representing the highest metamorphic grade that additionally contains chloritoid blasts. Pressure-temperature pseudosection modelling together with classical geothermobarometric calculations yielded peak metamorphic conditions of 0.94 ± 0.05 GPa and 550 ± 20 °C for chloritoid schist. Monazite in-situ U-Th-total Pb electron micro-probe dating indicates two metamorphic events at 167 ± 2 Ma and 143 ± 2 Ma, which are inter-preted as the time of monazite growth during two distinct metamorphic phases. The formation of the chloritoid paragenesis is related to the older event (around 167 Ma) and linked with the Middle Jurassic subduction-accretion processes of Neotethys-derived ophiolitic lithologies. The younger metamorphic event (around 143 Ma) is related to the obduction of ophiolites onto the continental margin of Adria.

Organisation(s)
Faculty of Earth Sciences, Geography and Astronomy, Department of Lithospheric Research
External organisation(s)
Croatian Geological Survey, University of Zagreb, Universität Stuttgart, China University of Geosciences
Journal
Geologia Croatica
Volume
76
Pages
13-36
No. of pages
24
ISSN
1330-030X
DOI
https://doi.org/10.4154/gc.2023.02
Publication date
02-2023
Peer reviewed
Yes
Austrian Fields of Science 2012
105120 Petrology, 105101 General geology
Keywords
ASJC Scopus subject areas
Geology, Earth and Planetary Sciences (miscellaneous)
Portal url
https://ucris.univie.ac.at/portal/en/publications/petrochronological-study-of-chloritoid-schist-from-medvednica-mountain-zagorje-midtransdanubian-zone-croatia(f874e66d-775f-4df0-8973-3bc31a63966d).html