Cyclostratigraphy and the astronomical time scale for the Tethyan Campanian (Late Cretaceous)
Short title: Campanian Orbital Cyclostratigraphy [CampOC]
2012-2015: Austrian Science Fund (FWF) Project P240/44-N24.
Ismail Omer Yilmaz (Middle East Technical University, Ankara, Turkey)
Jaume Dinares-Turell (Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy)
The CampOC project investigates cyclostratigraphy and astrochronology during the Campanian, the longest stage of the Late Cretaceous, based on Tethyan archives in Turkey and Austria.
The knowledge of the durations and the absolute timing of climatic and geological events recorded in the earth history, is a major issue in Earth science. A well calibrated and stable time scale is needed to allow for more precise dating of sedimentary archives of environmental and climate change.
The Cretaceous is known as the last long-term extreme greenhouse period of the earth history. The Campanian (83.5 – 70.6 Ma) is the longest Late Cretaceous stage. This interval constitutes a time of increasing climatic detoriation from mid-Cretaceous super-greenhouse to moderate greenhouse climate. So far, a complete record of climate-induced cyclicity and an astronomical time scale for the Campanian is lacking.
The proposed project addresses cyclostratigraphy and a floating astronomical time scale for the Campanian stage, based on four continuous cyclic limestone-marl records in the Tethys, i.e. two sections in Austria and two sections in Turkey. Methods used include plankton (foraminifera and calcareous nannofossil) biostratigraphy, carbon and strontium isotope stratigraphy and magnetostratigraphy for a high-resolution chronostratigraphic framework, the identification of cyclic sedimentation by rhythmic variations in parameters like carbonate contents, magnetic susceptibility, gamma ray log, and statistical analysis like data standardization, time series and power spectra analysis, wavelet transformation, and cross correlation between standardized measured parameters and solar insolation. The sedimentology and geochemistry of the sections in overview and of individual precessional cycles in the Campanian will be evaluated by clay mineralogy and XRF element scans.
Based on this new time calibration, short-term climate and environmental changes in the late greenhouse world will be investigated, especially causes for changes from anoxic to oxic sedimentation manifested in ubiquitous Cretaceous oceanic red beds.