Carbon isotope, greyscale and well-log data, Lower Turonian, Bohemian Cretaceous Basin

The study interval covers the latest Cenomanian through lower Middle Turonian (c. 94.5 – 92.5 Myr ago). New data on the carbon-isotope ratios in bulk organic matter (d13Corg) from the cores 4523-A (Sedlec) and 4530-A (Horní Beřkovice) document the major carbon-isotope anomaly of the Oceanic Anoxic Event II and small-scale isotope excursions of the Lower Turonian interval.

A greyscale-density profile of the core 4523-A and archive downhole resisitivity logs from two boreholes J-719670 and J-650704 provide high-resolution records of lithological variations of Milankovitch origin; these data were used to develop an astronomical time scale and interpret the phasing of orbital eccentricity in the study interval. A transient record of astronomical cyclicity was identified in major-element ratios (Si/Al) from the core Bch-1.