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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).

Model output for aerosol-induced cooling after the Chicxulub impact

The simulations of the end‐Cretaceous climate and the effects of the impact are carried out with a coupled climate model consisting of a modified version of the ocean general circulation model MOM3, a dynamic/thermodynamic sea ice model, and a fast statistical‐dynamical atmosphere model. Our impact simulations are based on a climate simulation of the end‐Cretaceous climate state using a Maastrichtian (70 Ma) continental configuration. The solar constant is scaled to 1354 W/m2, based on the present‐day solar constant of 1361 W/m2 and a standard solar model. A baseline simulation with 500 ppm of atmospheric CO2 and a sensitivity experiment at 1000 ppm CO2 concentration. The impact is assumed to release 100 Gt sulfur and 1400 Gt CO2. We simulate stratospheric residence times of 2.1 y, 4.3 y and 10.6 y. More information about the model can be found in the manuscript (https://doi.org/10.1002/2016GL072241).

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).

3D structural geological model of the Mallik Anticline, Canadian Arctic

The Mallik Anticline is a geologic structure in the Mackenzie Delta in the Canadian Arctic. Tectonics throughout the Cenozoic, with compressional phases in the early Eocene to the late Miocene, formed this large, domed structure that is today an important source of hydrocarbons. Gas hydrates occur in the clastic sedimentary rocks of the Oligocene to Pleistocene Kugmallite, Mackenzie Bay, and Iperk sequences, which were essentially formed by deltaic processes. The presence of hydrocarbon gases within the permafrost zone in the Canadian Arctic has led to extensive exploration and production activities in the region since the mid-1960s, and the investigations by geologists and geophysicists have already been published in numerous scientific articles to date. The associated report (Chabab and Kempka, 2023) describes the implementation of the first field-scale 3D static geologic model of the Mallik site, which was created using data from well logs and 2D seismic reflection profiles. The dataset presented here provides elevation depths and thickness data of the three distinct sequence boundaries Kugmallit-Richards, Mackenzie Bay-Kugmallit and Iperk-Mackenzie Bay as well as fault data from the Mallik site.

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