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Evolution of the Dinarides Fold and Thrust Belt: Paleogene Deformation and Neogene Post-Collisional Reorganization

The Late Cretaceous collision of the Adriatic microplate with Eurasia led to a predominantly southwest-vergent and in-sequence structural architecture in the Dinarides. During the Paleogene, the deformation front migrated from the Internal to the External Dinarides, resulting in about 130 km of crustal shortening. Fault kinematic data and balanced cross-sections across the External Dinarides reveal contrasting deformation styles along the orogen, separated by a roughly 250 km-long dextral transpressive fault. This fault marks the changes from the southern, southwest-vergent nappe stack segment to the northern, northeast-vergent backthrust-dominated Velebit segment. These backthrusts originated at lateral facies boundaries associated with extensional Mesozoic half grabens.

The contemporaneous deformation of these two domains, indicated by the distribution of flexural foreland basin sediments, marked the end of the Paleogene Dinaric orogeny. Within these Eocene to early Oligocene syntectonic and older Mesozoic carbonate platform rocks, horizontal marine terraces are preserved at elevations of up to 600 meters. Using digital elevation models (DEMs), we extracted terrace surfaces along the Adriatic coast, ranging from Istria in the north to Montenegro in the south. All these flat surfaces are degradational, unrelated to bedding or faults, and located between the present-day Adriatic shoreline and the drainage divide. The area of the extracted marine terraces corelates with a reported positive P-wave tomography anomaly. Based on the reported thinned Adriatic lithosphere beneath the internal part of the orogen, our findings suggest that the Dinarides underwent widespread surface uplift in the Miocene due to mantle delamination with limited Neogene crustal shortening.

Details

Author
Philipp Balling1, Bruno Tomljenović2, Stefan Schmid3, Christoph Grützner1, Marijan Herak4, Wim Spakman5, Kamil Ustaszewski1
Institutionen
1Friedrich-Schiller-Universität Jena, Germany; 2Institute of Geology & Geological Engineering, University of Zagreb, Croatia,; 3ETH-Zentrum, Zürich, Switzerland; 4Faculty of Science, University of Zagreb, Croatia; 5Utrecht University, Netherlands
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/phej-r407