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

Scientific paper - Original scientific paper

• Author: Mirko Belak
• Author: Damir Slovenec
• Author: Tea Kolar-Jurkovšek
• Author: Vesnica Garašić
• Author: Zoltan Pécskay
• Author: Darko Tibljaš
• Author: Ivan Mišur
• Author's institution: Croatian Geological Survey
• Author's institution: University of Zagreb; Faculty of Science; (Department of Geology)
• Author's institution: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Mineralogy, Petrology and Mineral Resources)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology

Abstract (english)

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).

• Keywords (english): Mt. Medvednica; greenschists; prograde–retrograde metamorphism; T-MORB; subduction–collision; Western Tethys
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Geologica Carpathica
• Numbering: vol. 73, no. 3, pp. 207-229
• p-ISSN: 1335-0552
• e-ISSN: 1336-8052
• DOI: https://doi.org/10.31577/GeolCarp.73.3.3
• URN:NBN: urn:nbn:hr:169:399722
• Publication: 2022-06-26
• Project: Number: IP-2019-04-3824; Title (croatian): Vulkano-sedimentne sukcesije sjeverozapadne Hrvatske i njihova uloga u razumijevanju geodinamike Paleotetisa tijekom srednjeg trijasa; Title (english): Revealing the Middle Triassic Paleotethyan geodynamics recorded in the volcano-sedimentary successions of NW Croatia; Acronym: GOST; Leader: Damir Slovenec; Jurisdiction: Croatia; Funding stream: IP
• Project: Number: 181-1811096-1093; Title (croatian): Osnovna geološka karta Republike Hrvatske 1:50.000; Title (english): Basic Geological Map of the Republic of Croatia 1:50.000; Leader: Mirko Belak; Jurisdiction: Croatia; Funding stream: ZP
• Document URL: http://www.geologicacarpathica.com/browse-journal/volumes/73-3/article-1008/
• Type of resource: Text
• Access conditions: Open access
• Created on: 2023-02-01 10:55:00