Cephalopods, small vertebrate fauna and stable isotope (δ13C, δ18O) record from the Jurassic-Cretaceous transition (uppermost Crassicollaria through Calpionella Zones) of the Outer Western Carpathians, Kurovice quarry (Czechia)
Abstrakt
An unusual and very important macrofauna has been recorded in the deep water environment (i.e. below the aragonite CCD) of the uppermost Tithonian - lower Berriasian carbonate calpionellid-bearing sequence of the Kurovice section (Czechia). Rhyncholites, belemnites, and small vertebrate fauna of elasmobranchians (Neoselachii) are reported herein from a submarine slump probably resulting from a tsunami-like event.
The Jurassic - Cretaceous (J/K) boundary interval is well demarcated by the occurrence of small globular Calpionella alpina, the J/K boundary marker established by the Berriasian Working Group. Rhyncholites, belemnites, and elasmobranchians are re-evaluated herein within the modern taxonomic concept, and they are stratigraphically investigated.
High resolution sampling provided new data on the stable isotope record (δ13C and δ18O) from the uppermost part of the Crassicollaria through the Calpionella Zones. The stable isotope record shows only minor excursions of the δ13C, with values below 0.5%o, and typically varying from 0.7%o to 1.2%o V-PDB; the most negative peak δ13C = 0.2%o V-PDB is recorded in the uppermost Crassicollaria Zone.
A slightly negative shift of carbon isotope values exceeds about 0.2%o at the J/K boundary. A similar trend at the critical J/K boundary interval (base of the Calpionella Zone) is seen in several Tethyan sections.
The δ18O curve shows larger excursions varying between -1.4 and -4.3%o V-PDB in the J/K boundary interval.