Structural curiosity of the northern Istria


  • Ladislav Placer



In northern Istria certain structural particularities exist that till now were not explained, and some of them not even known. They are all associated with underthrusting of the Adriatic microplate (Istra) under the Dinarides. The Rokava fault of cross-dinaric direction was discovered that exerts an important influence on hydrographic pattern in this part of Istria. The cross-dinaric sinistral strike-slip faults above Glinščica stream (Rosandra) are of local importance only, since at Kastelec and Črni Kal the dextral strikeslip faults of NNW-SSE direction occur as their conjugated equivalents. This particular feature has been named the Gročana (Grozzana) structure. The reason for such a structure is the echelon folding (complete folding) in the Istrian hinterland (the Kras-Notranjsko folded structure). In the Tinjan area a wedge shaped block occurs between two thrust faults that are turned up and quite steep owing to secondary folding. The wedge is open northwestward, and the flysch beds within it are folded in the cross-dinaric direction. They represent an indication of lateral squeezing in a limited area, since in the close-by roadcut of the Ankaran-Trieste motorway no trace of these folds remains (the Tinjan structure). In the Izola and Strunjan area a complex overthrust structure is present that rapidly wedges out toward central Istria. Indirect data suggest that it extends northwestward below the Bay of Trieste. The elements of this structure are the Izola thrust fault with Izola anticline in the thrust block, and folds at Strunjan that were formed in the belt between the reverse overthrusts in the Strunjan bay and Izola thrust fault area (the Strunjan structure).


How to Cite

Placer, L. (2005). Structural curiosity of the northern Istria . Geologija, 48(2), 245–251.