EGU21-9036
https://doi.org/10.5194/egusphere-egu21-9036
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Devonian magnetostratigraphy: new data and old problems

Annique van der Boon1, Andy Biggin1, Daniele Thallner1, Mark Hounslow2, Jerzy Nawrocki3, Kristyan Wójcik3, Mariusz Paszkowski3, Peter Königshof4, Tim de Backer5, Pavel Kabanov6, Sofie Gouwy6, Richard Vandenberg6, and Richard Bono1
Annique van der Boon et al.
  • 1University of Liverpool, Geomagnetism Laboratory, Earth, Ocean and Ecological Sciences, United Kingdom of Great Britain – England, Scotland, Wales (avanderboon.work@gmail.com)
  • 2Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
  • 3Polish Geological Institute – National Research Institute, Warszawa, Poland
  • 4Senckenberg Research Institute and Natural History Museum, Frankfurt, Germany
  • 5Department of Geology, Ghent University, Ghent, Belgium
  • 6Geological Survey of Canada, Calgary, Canada

The global polarity time scale (GPTS) is relatively unconstrained for the Paleozoic, particularly the Devonian. Constraining the GPTS and reversal frequency for the Devonian is crucial for the understanding of the behaviour of Earth’s magnetic field. Furthermore, construction of a GPTS for the Paleozoic could provide a valuable tool for age determination in other studies. However, most paleomagnetic data from the Devonian is problematic. The data are difficult to interpret and don’t have a single easy to resolve (partial or full) overprint. Paleointensity studies suggest that the field was much weaker than the field of today, which could have been accompanied by many reversals (a hyperreversing field). In order to improve the geomagnetic polarity time scale in the Devonian, and quantify the number of reversals in this time, we sampled three Devonian sections in Germany, Poland and Canada. These sections show evidence that the rocks were not significantly heated, and they show little evidence for remineralisation. This minimises the chance the rocks were remagnetised after the Devonian. Our data show that even when rocks are well qualified to have reliably recorded the Devonian field, the interpretation is not straightforward. We also discuss problems with the Devonian GPTS as presented in the geologic timescale.

How to cite: van der Boon, A., Biggin, A., Thallner, D., Hounslow, M., Nawrocki, J., Wójcik, K., Paszkowski, M., Königshof, P., de Backer, T., Kabanov, P., Gouwy, S., Vandenberg, R., and Bono, R.: Devonian magnetostratigraphy: new data and old problems, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9036, https://doi.org/10.5194/egusphere-egu21-9036, 2021.

Corresponding formerly uploaded have been withdrawn.