Project Details
Projekt
Forming a consistent astrochronology for the Cretaceous C-sequence of the Geomagnetic Polarity Time Scale (66 to 84 Ma)
Applicant
Dr. Thomas Westerhold
Subject Area
Geology
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 565797127
Alterations in Earth's magnetic field, particularly the reversal of its polarity, have been documented in geological rock records. The sequences of normal (north) and reversed (south) polarity, which alternate irregularly, have been identified in seafloor magnetic anomaly profiles and terrestrial sequences. This barcode-like pattern has been calibrated in time and is referred to as the Geomagnetic Polarity Time Scale. Magnetostratigraphy involves the documentation of these reversals in individual sedimentary successions, aligning them with the Geomagnetic Polarity Time Scale. The advantage of employing these features for global correlation lies in the geologically rapid completion of reversal processes, occurring within a few thousand years, synchronous worldwide. The goal of this study is to test and refine the Upper Cretaceous Geomagnetic Polarity Time Scale, from the base of Chron C30n to the top of Chron C34n, and to establish astronomically calibrated ages by correlation to astrochronological reference records. Astronomically calibrated ages for the Cenozoic part of the Geomagnetic Polarity Time Scale are provided as part of the Cenozoic Global Reference benthic foraminifer carbon and oxygen Isotope Dataset (CENOGRID, Westerhold et al. 2020), but not for the late Cretaceous portion of the so called C-Sequence. Here we want to fill this gap and additionally test a new approach to combine paleomagnetic data from several sites by correlation via bulk carbonate stable carbon isotope data and subsequent integration to an astronomically tuned reference. This approach allows to minimize the age error and timing of the reversal, and the potential to refine the Late Cretaceous Geomagnetic Polarity Time Scale C-Sequence ages which then can function as a reference for global correlation of geological data.
DFG Programme
Infrastructure Priority Programmes
International Connection
Italy
Cooperation Partner
Edoardo Dallanave, Ph.D.
