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

This dataset includes geochemical and geophysical data obtained from four boreholes in the western part of the Bohemian Cretaceous Basin (central Europe). 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.

Carbon isotope ratios in bulk organic matter (δ¹³Corg), sediment core 4530-A

This file includes new data on the carbon-isotope composition of bulk organic matter (δ¹³Corg) from the core 4530-A (Horní Beřkovice), western part of the Bohemian Cretaceous Basin. The interval covers the uppermost Cenomanian through Middle Turonian. Samples were analyzed in the Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University, Prague. Stable isotopic composition of carbon was determined using a Thermo Flash 2000 elemental analyzer connected to a Thermo Delta V Advantage isotope ratio mass spectrometer in a Continuous Flow IV system. Minimal weight of samples depends on the wt.% amount of carbon element. Samples wrapped in tin capsules were combusted. Released gases (CO2) separated in a GC column was transferred to MS source through a capillary. Isotope ratios are reported as delta (δ) values and expressed relative to VPDB. Delta values are normalized to a calibration curve based on international standards IAEA-CH-6, IAEA-CH-3 and IAEA 600.

Carbon isotope ratios in bulk organic matter (δ¹³Corg) and organic carbon contents (TOC), sediment core 4523-A

This file includes new data on the carbon-isotope composition of bulk organic matter (δ¹³Corg) and organic carbon contents (TOC, wt%) from the core 4523-A (Sedlec), western part of the Bohemian Cretaceous Basin. The interval covers the uppermost Cenomanian through Middle Turonian. Samples were analyzed in the Stable Isotope Laboratory of the Geological Survey, Prague. Inorganic carbon was removed before analysis by acid washing with HCl followed by rinsing with water, drying at 60 °C and homogenisation. Carbon-isotope measurements were performed by flash combustion in Fisons 1108 elemental analyzer coupled with isotope ratio mass spectrometer Delta V Advantage (ThermoFisher, Bremen, Germany) in continuous flow regime. Sample size was adjusted to contain a sufficient amount of carbon. Isotope ratios are reported as delta (δ) values and expressed relative to VPDB. International standards NBS 22 (-30,031‰), IAEA-CH-7 (-32,151‰) and in-house standard Soil (-27,82 ‰) were used to verify proper instrument function, and to conduct a normalization procedure. The long-term reproducibility is better than ±0.15‰.

Greyscale density, sediment core 4523-A

This file includes new data on the greyscale density (8-bit) from the core 4523-A, western part of the Bohemian Cretaceous Basin. The interval covers the uppermost Cenomanian through Middle Turonian. The data were extracted from high-resolution (~10 pixels/mm) photographs using the image-processing software ImageJ (National Institutes of Health, Bethesda, MD).

Downhole resistivity log, borehole J-719670

This file includes archive data on the electrical resistivity from borehole J-719670, western part of the Bohemian Cretaceous Basin. The interval covers the uppermost Cenomanian through Middle Turonian. The original files are stored in the GEOFOND archive of Czech Geological Survey (Kostelní 26, Praha 7).

Downhole resistivity log, borehole J-650704

This file includes archive data on the electrical resistivity from borehole J-650704, western part of the Bohemian Cretaceous Basin. The interval covers the uppermost Cenomanian through Middle Turonian. The original files are stored in the GEOFOND archive of Czech Geological Survey (Kostelní 26, Praha 7).

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