In this master's thesis I describe the Middle and Upper Triassic (Ladinian to Lower Carnian) rock sequence in the area of the Rute Plateau, west of Velike Lašče. The investigated region structurally belongs to the External Dinarides and is situated on a deformed paleorelief, which was formed after disintegration of the Slovenian Carbonate Platform at the end of the Anisian stage. In the beginning of the Ladinian, deep marine sediments began to deposit in small basins or tectonic depressions, whereas on elevated or relatively less sunken tectonic bloks (isolated platforms) carbonate sedimentation was still going on. During the Ladinian, tectonic movements were also accompanied by volcanic activity. Whereas the progradation of carbonate platforms, at the end of the extension in the late Ladinian to early Carnian, generally led to a more homogeneous relief, on the Rute Plateau, in the late Ladinian, another small subsidence occurred instead. It was followed by an additional volcanic episode. Elsewhere, the growth of platforms was interrupted only at the end of the early Carnian due to a regional sea level fall. Finally, in the late Carnian deposition of clastic sediments started and continued until the gradual formation of the Main Dolomite. The aforementioned happenings in the Middle Triassic are recorded on the Rute Plateau as a variegated sequence of sedimentary and volcaniclastic rocks of Ladinian and Carnian age. With the help of five stratigraphic profiles that cover different paleogeographic parts of the original depositional environment, I defined different stratigraphical sequences (units). Based on a unit’s work name, profiles display the vertical and lateral repeatability of some units and differences in stratigraphical development of the researched area. Profiles are organised according to most distal successions, ranging more towards the basin area and proximal successions, which are closer to the carbonate platform. Based on the results of this research, I manage to divide the studied area into five different lithostratigraphic units, comprised of individual or united lithological units. Last but not least, conodont determinations also confirmed some mistakes in the interpretation of the Mohorje formation. The lowermost part of the formation, the Boštetje member, composed of black platy and laminated micritic limestone, is not actually Carnian but is most probably of Ladinian age. In the future we propose a detailed age revision of the entire Mohorje formation and stratigraphical reambulation of the Rute Plateau.
|
