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New evidence for Alpine overprint of poly-deformed gneisses in the ‘Median Dacides’ of SE Europe: restoring polyphase deformations and transposition cycles.
- Source :
-
International Geology Review . Sep2024, p1-32. 32p. 15 Illustrations. - Publication Year :
- 2024
-
Abstract
- The outcrop and microscale structural constraints on metamorphosed fragments of Carpathian-Balkan exotic north Gondwanan continental crust show sequential recurrent peripheral subduction processes which produced a series of collisional orogens: (i) Variscan suturing of ‘Median Dacides’ (western Danubian/Moesian realm), and (ii) post-dating polystage Alpine overprinting. The ‘Median Dacides’ comprise the two gneiss-bearing amphibolite-facies, Serbo-Macedonian and Getic/Kučaj basements, embedded into Southern Carpathians (Romania) and Carpathian-Balkans (Serbia, North Macedonia, Bulgaria). To unravel polyphase deformation processes, we have incorporated the data available on Neoproterozoic-Lower Palaeozoic protoliths and tectonometamorphic events, coupling these with new extensive structural field-based analysis. The deformation patterns expose polystage deformation history (D1-2), fashioned by the youngest Alpine overprinting (D3-4). The structural data and protolith analyses suggest a Lower Palaeozoic Cadomian-to-Cenerian geodynamic linkage between the two gneissic basements. Notably, the pre-Variscan anatexis, migmatitization, metamorphism (D1-1), and the formation of Cenerian (axial planar) foliation (D1-2) are precursors of the tight isocline Variscan folds (D2-1). Progressive deformation of the initial Variscan structural fabric (metre-scale folds) produced complete transposition (D2-2) with scarcely preserved metre-scale folds. The successor Alpine shortening (D3) (re)activated the existing remnants of Variscan axial plane cleavages (or overlapped foliation-to-cleavage planes), further producing schistosity and folding pattern preserved due to the partial transposition. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00206814
- Database :
- Academic Search Index
- Journal :
- International Geology Review
- Publication Type :
- Academic Journal
- Accession number :
- 179570671
- Full Text :
- https://doi.org/10.1080/00206814.2024.2397416