Christian Zeeden^a,b, Jacques Laskar^a, David De Vleeschouwer^d, Damien Pas^e, Anne-Christine Da Silva^c
Earth and Planetary Science Letters (in Press) Link to Article [https://doi.org/10.1016/j.epsl.2023.118348]
^aIMCCE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, 75014 Paris, France
^bLIAG – Leibniz Institute for Applied Geophysics, Stilleweg 2, 30655 Hannover, Germany
^cPétrologie sédimentaire, B20, Allée du Six Août, 12, Quartier Agora, Liège University, Sart Tilman, 4000 Liège, Belgium
^dInstitute of Geology and Paleontology, Westfälische Wilhelms-Universität (WWU) Münster, Corrensstr 24, 48149 Münster, Germany
^eInstitute of Earth Sciences (ISTE), University of Lausanne, CH-1015 Lausanne, Switzerland
Copyright : Elsevier

Astronomical insolation forcing plays an important role in pacing Earth’s climate history, including paleoclimate dynamics, and its imprint can be seen in various geoarchives. Its signature is often evident through typical rhythmic patterns in sediments. The detailed study of those patterns led to a better understanding of orbital climate forcing, while also providing more precise constraints on the geological time scale. Due to the tidal evolution in the Earth-Moon system, the precession and obliquity periods get shorter when going back in time while the main eccentricity 405 kyr period remains stable. While several astrophysical models describe the evolution of the length of precession- and obliquity cycles, few reliable and quantitative geological information from tidalitesand astrochronology are available.

To better constrain these key astronomical parameters in the distant past, we calculate precession and obliquity properties for the Devonian (∼420-360 million years before present) as reconstructed from a suite of geological datasets. Our results show the period of precession to be 19.4-16.1 kyr, and the dominant p+s3 obliquity period to be 29.50±0.46 long. These findings are compared with and support the presence of oceanic tidal resonances at 300 and 540 Ma, as shown in the recent AstroGeo22 model of the Earth-Moon evolution of (Farhat et al., 2022).