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A global paleosecular variation database for the Paleogene: stationary secular variation behavior since the Triassic?
  • +6
  • Y A Engbers,
  • D Thallner,
  • R K Bono,
  • C J Sprain,
  • M J Murray,
  • K Bristol,
  • B Handford,
  • T Torsvik,
  • Andrew Biggin
Y A Engbers
Department of Earth, Ocean and Ecological Sciences, Geomagnetism Laboratory, University of Liverpool, Electromagnetic Signatures and Propagation, Netherlands Organization for Applied Scientific Research (TNO)
D Thallner
Department of Geological Sciences, University of Florida
R K Bono
Department of Earth, Ocean and Atmospheric Science, Florida State University
C J Sprain
Department of Geological Sciences, University of Florida
M J Murray
Department of Earth, Ocean and Ecological Sciences, Geomagnetism Laboratory, University of Liverpool
K Bristol
Department of Geological Sciences, University of Florida
B Handford
Department of Earth, Ocean and Ecological Sciences, Geomagnetism Laboratory, University of Liverpool
T Torsvik
Center for Planetary Habitability (PHAB), University of Oslo, School of Geosciences, University of Witwatersrand
Andrew Biggin

Corresponding Author:[email protected]

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Abstract

Paleosecular variation analysis is a primary tool for characterizing ancient geomagnetic behavior and its evolution through time. This study presents a new high-quality directional dataset, paleosecular variation of the Paleogene (PSVP), with and without correction for serial correlation (SC), compiled from 1,667 sites from 45 different localities from the Paleogene and late Cretaceous (84 – 23 Ma). The dataset is used to study the variability, structure, and latitude dependence of the geomagnetic field during that period by varying selection criteria and PSV models. Modeled values for the equatorial virtual geomagnetic pole (VGP) dispersion have over-lapping uncertainty intervals within their uncertainty bounds between 8.3° and 18.6° 30 for the past 250 Ma. We investigate the suitability of two descriptive models of PSV, Model G-style quadratic fits and covariant GGP models, and find that both styles of model fail to satisfactorily reproduce the latitude dependent morphology of PSV,  but suggest that estimates of the equatorial VGP dispersion may still robustly characterize aspects of Earth’s long-term field morphology. During this time where the PSV behavior has not changed substantially, the reversal frequency has varied widely. The lack of a clear relationship between PSV behavior and reversal frequency is not trivially explained in the context of published findings regarding numerical geodynamo simulations.
This manuscript is the version accepted for publication in G-Cubed on 16th May, 2024.
26 May 2024Submitted to ESS Open Archive
28 May 2024Published in ESS Open Archive