A series of panels showing the substantial number of new quality data published for the three geomagnetic elements, declination (left), inclination (center), and intensity (right) with geographical distribution on the top row and temporal distribution on the bottom row.
The panels show the substantial number of new quality data published for the three geomagnetic elements: declination (left), inclination (center), and intensity (right). The paler colors indicate data available up to 2009 and darker colors after 2009. Of particular note is the intensity data base, which tripled since 2009. The top row shows the geographical distribution within the spherical cap while the bottom row of panels shows the temporal distribution. With this massive number of data, the new model by Pavón-Carrasco et al. [2021] describes the secular variation in space and time for Europe and surroundings for the last 4000 years for any point within the spherical cap, 1000 years longer than their previous 2009 model. Credit: Pavón‐Carrasco et al. [2021], Figure 2
Source: Journal of Geophysical Research: Solid Earth

Regional (spherical cap) and global field models are data-driven models that describe the behavior of the geomagnetic field in high resolution for the most recent couple of thousands of years, used to quantify certain field features such as westward drift.

Pavón‐Carrasco et al. [2021] select quality data (both from a geomagnetic point of view and an age dating point of view!) and produce a new spherical cap geomagnetic field model for Europe and surroundings, including the Middle East. They favor spherical caps over global field models for regions with sufficient data coverage, such as Europe, because less extrapolation is required which inherently leads to smooth models. Because now sufficient data are available, the new model captures the Levantine Iron Age Anomaly, a short-lived intensity spike about 3000 years ago in the Middle East, a marked achievement. Its westward movement can be tracked as well, furthering our understanding of the geomagnetic field.

Knowing field behavior in great detail is also important for archeology because it offers a versatile dating tool for burnt structures that record their last usage (or unintentional burning) by locking the ambient geomagnetic field at the time into a permanent magnetic moment. It complements Carbon-14 dating for the last couple of millennia. With the field model and the accompanying web application one can generate the field behavior as function of time for the location of the archeological site itself thus bypassing the error that is made by relocating the site to the location of the related secular variation master curve. This relocation is made on the assumption of a geocentric axial dipole field (one cannot do otherwise) while the field model includes all data and thus takes into account non-dipole contributions.

Citation: Pavón‐Carrasco, F. J., Campuzano, S. A., Rivero‐Montero, M., Molina‐Cardín, A., Gómez‐Paccard, M., & Osete, M. L. [2021]. SCHA.DIF.4k: 4,000 years of paleomagnetic reconstruction for Europe and its application for dating. Journal of Geophysical Research: Solid Earth, 126, e2020JB021237. https://doi.org/10.1029/2020JB021237

—Mark J. Dekkers, Associate Editor, JGR: Solid Earth

Text © 2021. The authors. CC BY-NC-ND 3.0
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