Microfacies analysis of limestones from the Upper Cretaceous to the Lower Eocene of SW Slovenia (Yugoslavia)
A microfacies analysis of limestone samples from NW Yugoslavia (Slovenia) was carried out. The microscopic observations were complemented with palynological and geochemical data including determination of isotopic ratios. The findings point to a regressive development which took place during the Senonian and culminated in karst and subsequent bauxitization. In a later stage of subaerial exposure, calichification occurred overlapping the karst facies. At the beginning of the Tertiary, a transgression unfolded and the Kozina limestones started to form. Due to sea level changes and climatic factors, these sediments show superimposed palustrine and brackish intertidal to subtidal horizons which were diagenetically altered thus presenting a complicated facies pattern. Overlaying the Kozina limestones, the Late Paleocene Miliolid limestones occur. These are brackish intertidal to subtidal sediments that underwent prolonged periods of subaerial exposure, too. There is a gradual predominance of marine organisms in the vertical sequence that reaches its maximum in the next unit, the Alveolina- Nummulites limestones (Early Eocene). The three stratigraphic units dealt with in this study reflect gradual but important facies changes which are stressed here.