When is little data enough data?

Paleomagnetic data

Rocks and archaeological material also show paleomagnetic vectors at the time of their formation. These provide information about the structure of the magnetic field over the course of the Earth's history: the geomagnetic field usually resembled a geocentric dipole aligned with the axis of rotation. In general, however, the recorded paleomagnetic vectors deviate from this simple model at specific times and specific locations. Paleomagnetic datasets, which were created over several decades, help to define the global magnetic field behavior in the past.

New model for the selection of high-quality paleomagnetic data

Lisa Tauxe, David Heslop and Stuart Gilder have updated the compilation of paleomagnetic data and created a new field model that is representative of the last 10 million years. Earlier or more recent data sets can be compared to this new model to see if the two match in terms of field structure and variability. The authors of the new method (SVEI) have tested data sets up to 1.1 billion years old and found them all to be compatible with the model.

Applications of the SVEI method for sedimentary rock

In addition, SVEI can also evaluate and possibly correct data from sedimentary rock that may have been affected by slope flattening. The advantage over other correction methods is the more complete description of the geometry of the directional data and the quantitative comparison of the empirical and predicted distributions. SVEI can also be used to correct slopes and their uncertainties. This is crucial for the determination of paleolatitudes, the basis for plate tectonic and paleoclimatic reconstructions.

Summary of the publication

• Update of the database for paleosecular variations from lava flows (PSV10-24) for the last 10 Ma
• Definition of a new Giant Gaussian Process (GGP) model (THG24) that is compatible with PSV10-24 and contains VGP scattering with data sets from 1.1 Ga upwards
• Description of the SVEI method (an update of E/I) for the assessment of secular variation records and correction of slope flattening in sediments

Information on the publication:

Tauxe, L., Heslop, D., & Gilder, S. A. (2024). Assessing paleosecular variation averaging and correcting paleomagnetic inclination shallowing. Journal of Geophysical Research: Solid Earth, 129, e2024JB029502. https://doi.org/10.1029/2024JB029502

Link to the code of the SVEI method on Github PmagPy