The studied flysch sequence is located on the southern slopes of the Vipava Valley, in the west of Slovenia. The area is geotectonically a part of External Dinarides, rather of Komen thrust sheet.
Paleogeographically, the area belongs to the Adriatic-Dinaric Carbonate Platform, the decay of which accelerated in the Paleocene and Eocene. Its northern edges gradually sank and deep-sea flysch sedimentation began in the flexural basin. The flysch consists mainly of medium-grained sandstone, siltstone and marl, and of intermediate layers of resedimented carbonates, which can occur in very thick layers known as large layers or mega-layers. Most carbonate mega-layers are formed by calcarenites, conglomerates and breccias, in which lithoclasts of Paleocene and Eocene shallow-sea carbonates and isolated bioclasts are present.
In the research paper, one of the carbonate mega-layers is described in more detail and it represents a layer of Planina breccia at least 30 meters thick, which forms a flattened karst plateau, up to 400 meters in height, on the southern slopes of the Vipava Valley. The breccia was formed by debris flow, which was transported from the south, and the rest of the flysch sequence was transported by turbidite flows from the north.
As part of the research task, I described in detail two sedimentological profiles and performed geological-geomorphological mapping of the area Planina above Ajdovscina. During the mapping, I determined the lithostratigraphic boundary between breccia and flysch in several places, I marked surface karst phenomena and listed 15 calciturbidites. The latter are composed of calcarenite, which ends up with a different thickness marly cap. The final result of the research task is a geological-geomorphological map and a detailed sedimentological analysis of Planina breccia.
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