The diploma presented a morphological and sedimentological analysis of rhodoliths from Badenian deposits of the Laško Formation in the Srebrnik area, Kozjansko, Slovenia. The aim of the study was to characterize the morphology of the rhodoliths, compare specimens from two stratigraphic horizons, and interpret the depositional conditions based on their external morphology and internal structure. A total of 153 rhodoliths were analysed, including 144 specimens from the lower horizon and nine from the upper horizon. Three main axes were measured, and macroscopic analyses of the external surfaces and cross-sections of the rhodoliths were performed together with sedimentological analyses of rocks and thin sections. Rhodoliths from both horizons were comparable in size but differed mainly in shape. The lower horizon was dominated by more flattened and discoidal rhodoliths, which were commonly oriented parallel to bedding, whereas the upper horizon contained more equidimensional to spheroidal specimens without a pronounced preferred orientation. Differences in axis ratios between the two horizons were statistically significant. The internal structure revealed concentric to undulating algal crusts, diverse nuclei, growth interruptions, and bioerosional structures, indicating multiphase rhodolith growth. Sedimentological analysis identified organogenic boundstone and bioclastic packstone. Based on the combined morphological, taphonomic, and sedimentological characteristics, the rhodoliths were interpreted as having developed in a dynamic shallow-marine environment. Differences between the two horizons were primarily attributed to variations in hydrodynamic conditions, substrate stability, and the frequency of rhodolith movement on the seafloor.
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