The Cenomanian/Turonian boundary event in Central Poland
Abstract Stable isotopes (13C, 18O), CaCO3 content, carbon content insoluble in HCl (Corg) and in the carbonates (Ccarb), and foraminifers have been investigated in the Cenomanian/Turonian boundary interval (Rotalipora cushmani Zone and lower Whiteinella archaeocretacea Zone) in southeast Central Poland. A higher content of Corg in the uppermost Rotalipora cushmani Zone and lowermost Whiteinella archaeocretacea Zone, a δ13C and δ18O stable isotope anomaly in the uppermost Cenomanian, and substantial changes in the foraminiferal assemblages have been recorded. A major carbon stable isotope excursion with a shift of up to +1.6‰ (PDB) recorded in the lower part of the Whiteinella archaeocretacea Zone within the marly limestone in the uppermost Cenomanian. A late Cenomanian expanding oxygen minimum zone is thought to be responsible for changes in foraminiferal assemblages.