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https://doi.org/10.4154/gc.2026.06

Tectogenic carbonate breccia (Jelar/Velebit breccia) in the Northern Velebit National Park, SW Croatia: Structural emplacement and breccia lithotypes

Bojan Matoš orcid.org/0000-0002-7686-3721 ; University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Zagreb, Croatia
Darko Matešić ; University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Zagreb, Croatia *
Uroš Barudžija orcid.org/0000-0002-1617-9362 ; University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Zagreb, Croatia
Dubravka Kljajo ; Northern Velebit National Park Public Institution, Krasno, Croatia
Igor Vlahović orcid.org/0000-0002-7445-7623 ; University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Zagreb, Croatia

* Dopisni autor.

Prilozi: GC_79_2_Matos et al. (2026) suppl.pdf

Sažetak

The Velebit Mt. was uplifted by multistage tectonics resulting in the formation of an approximately 150 km long, NW–SE striking anticline comprising a Late Palaeozoic to Cenozoic carbonate-clastic succession, with a major orogenic event in the younger Palaeogene. This study focused on the tectonostratigraphic investigation of a massive Tectogenic carbonate breccia (TCB) studied in the Northern Velebit area, known in the Croatian literature as the Jelar or Velebit breccia. Results of field investigations along eight profiles show that the Northern Velebit represents an ENE-verging fold formed by general E–W (ENE–WSW) contraction in the hangingwall of the NNW–SSE oriented fault, a terminal strand of the NW–SE striking Bakovac Fault Zone. The Palaeogene (–Early Miocene?) and post-Early Miocene tectonic activity resulted in NNW–SSE/ESE–WNW oriented compression, followed by NE–SW and NW–SE extension as a result of the gravitational collapse of the Northern Velebit anticline. N–S and E–W striking dextral/sinistral faults suggest NW–SE/NE–SW and ESE–WNW oriented transpression/transtension in the Northern Velebit area after the Early Miocene. Repeated structural reactivation/tectonic inversion within the Northern Velebit anticline hinge area affected the Jurassic–Cretaceous carbonates, especially along the strike of the fault/fracture systems, which resulted in prolonged brittle deformation, i.e., cataclasis, brecciation, and formation of the TCB. Within the part of the study area marked as carbonate breccia on existing geological maps, on average, 67% of eight studied profiles are actually composed of Upper Jurassic and Cretaceous limestones (and some dolomites). Between those rocks and the TCB typically a transitional zone from metres to a few tens of metres wide can be observed, composed of (1) intensely tectonised limestones/dolomites, and (2) crackle/mosaic carbonate breccia, covering approximately 12% of the total profile length. Tectogenic carbonate breccia in the study area are mostly represented by (3) monomictic carbonate breccia and (4) polymictic carbonate breccia, while (5) carbonate conglomerates and breccia-conglomerates form only rare small lenses. TCB lithotypes crop out along approximately 21% of the profile length marked as carbonate breccia on the existing geological maps of the study area. Most of the TCB outcrops were observed in the central zone of the Northern Velebit, while intensely tectonised limestones, crackle/mosaic carbonate breccia and Upper Jurassic and Cretaceous carbonate rocks predominate in the eastern and western parts.

Ključne riječi

Velebit Mt.; External Dinarides; Palaeogene (–Early Miocene?) stress regime; post- Early Miocene stress regime; fractured limestone; crackle/mosaic breccia; monomictic/ polymictic carbonate breccia; Jelar/Velebit breccia

Hrčak ID:

348065

URI

https://hrcak.srce.hr/348065

Datum izdavanja:

25.5.2026.

Posjeta: 0 *