Naslov
Low-grade metamorphic rocks of the Tethys subduction– collision zone in the Medvednica Mt. (NW Croatia)

Autori
Belak, Mirko ; Slovenec, Damir ; Kolar-Jurkovšek, Tea ; , Garašić, Vesnica ; Pécskay, Zoltan ; Tibljaš, Darko ; Mišur, Ivan

Izvornik
Geologica Carpathica (1335-0552) 73 (2022), 3; 207-229

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Mt. Medvednica, greenschists, prograde–retrograde metamorphism, T-MORB, subduction–collision, Western Tethys

Sažetak
The low-grade metasedimentary rocks of Medvednica Mt. (Northwest Croatia) are associated with orthogreenschists (metabasalts). The Lower to Upper Triassic age of the protolith of the low-grade metamorphic rocks belonging to the Stari Potok, Adolfovac, Tusti Breg, Bliznec, Mrzljak, and Sljeme lithostratigraphic units is determined on the basis of conodonts and field relationships. The metamorphic age of the Triassic metasedimentary rocks from the Risnjak lithostratigraphic units is assumed to be Jurassic. Petrographic and geochemical analyses of ortho-greenschists point to a tholeiite basic magmatic protolith rock having T-MORB (transitional midocean-ridge basalt) characteristics. The ortho-greenschists of the Sljeme lithostratigraphic unit underwent retrograde metamorphism and show metamorphic zoning from the epidote–amphibolite facies to the lower parts of the greenschist facies. However, the greenschists of the Tusti Breg and Bliznec units are characterized by prograde metamorphism ranging from lower to higher greenschist facies. This metamorphism is associated with Jurassic subduction (165–150 Ma) and closure of the Western Tethys. Retrograde metamorphism took place during the collision of the Adriatic and Eurasian plates in the Lower Cretaceous (125–110 Ma).

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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