Cretaceous–Tertiary boundary problem on shallow carbonate platform: Carbon and oxygen excursions, biota and microfacies at the K/T boundary sections Dolenja Vas and Sopada in SW Slovenia, Adria CP

The transition of Maastrichtian to Danian in SW Slovenia was studied in two shallow marine carbonate successions. Apart from the extinction of some biota, the K/T boundary is reflected also in carbonate isotopic composition and in geochemistry. The K/T boundary is characterized by 20 cm to 1 m thick sedimentary breccia of intertidal origin. Extreme depletion in the δ13C content (up to − 8‰) was found in Dolenja Vas section just at this boundary. It related to global climatic changes caused by impact of extraterrestrial body followed by the destruction and combustion of terrestrial plants. Slight enrichment in δ13C content (up to 2‰) is evident at Danian/Selandian boundary too.