The Mežakla plateau in the Julian Alps reaches 1348 meters above sea level. It is located between the rivers Radovna to south and west, and Sava Dolinka to the north. Its eastern border extends to Blejski kot and the Vintgar Gorge. Detailed mapping showed that the northeastern part of Mežakla structurally belongs to the Krn Nappe, which is the lowest of the Julian nappes in the eastern Southern Alpes. On the other hand, the southwestern part of the plateau shows stratigraphic evolution distinctive for the Pokljuka nappe.
In this master´s thesis, Pelsonian succession from section near Obranca is studied and presented. A 195 m long sedimentological section was logged and sampled for thin sections. The latter were used for detailed microfacial and biostratigraphic analysis. The interpretation of sedimentary evolution is given.
Our results show that the Anisian succession in the northeastern part of the Mežakla plateau closely resambles the stratigraphic succession from the Kamnik-Savinja Alps. The base of the succession on the Mežakla plateau is represented by Anisian dolomite. On the northeastern-most part of the plateau, the Anisian dolomite is followed by thick-bedded limestones, whereas in the central part of the plateau the Anisian dolomite is followed by thin-bedded laminated black bituminous limestone, equivalent tot he Strelovec Formation and/or the Velika planina Member. Sinsedimentary folds, slumps and small-scale faults and turbidites are evidence of sedimentation on the slope and/or higher tectonic activity. Upwards, the thin-bedded laminated black bituminous limestone gradually passes into bedded limestone, dolomite and dolomitized limestone. The alternation of thin-bedded black bituminous limestone and bedded limestone, dolomite and dolomitized limestone is observed three times in the entire succession. The Pelsonian age of the succession was determined based on the cross-section of the ranges of Pilammina densa, Aulotortus? eotriasicus, Trochammina jaunensis and Citaella dinarica foraminifera species.
The succesion shows repeated shallowing of restrictive intraplatform basin, which is conditioned by synsedimentary tectonics. Throughout the Mežakla plateau, the platform progradation can be observed with lateral and upwards transition into massive dolomite and limestone, which shows the final filling of the basin during Pelsonian and upper Anisian age.
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