New Italian directional and intensity archaeomagnetic reference curves for the past 3000 years: Insights on secular variation and implications on dating

Abstract

We present the first Italian reference secular variation curves for both direction and intensity that cover the last 3000 years. Strict selection criteria were applied to guarantee the collection of the most reliable data within a 1000 km radius of Viterbo, including archaeomagnetic records from archaeological material and volcanic rocks. The new curves are calculated using Bayesian statistics and they depict interesting geomagnetic field features, such as high‐intensity periods. These are the first curves for Italy, including both directional and intensity data, and they can be used as reference curves for archaeomagnetic dating, not only in Italy but also in nearby countries.

Global archaeomagnetic data: The state of the art and future challenges

“…Therefore it has been common to develop regional archaeomagnetic curves. It is generally assumed that data within a radius of several 100 to a few 1000 km reflect similar field variations and can be combined to form a reference curve for a region (e.g., Tarling, 1989;Tema and Lanos, 2020). A review by Korte et al (2019) included an investigation of the spatial correlation length of geomagnetic variations and the possible influence of the distance to a curve for dating accuracy.…”

How did the dipole axis vary during the first millennium BCE? New data from West Europe and analysis of the directional global database

“…Figure 5 compares the new French and Italian archaeodirections with all existing data, without selection, in each country between 1400 and 0 BCE. The new data are also plotted against the master curves of Hervé & Lanos (2018) for France and Tema and Lanos (2020) for Italy that also included data from neighbouring countries within 1000 km of Paris and Viterbo respectively. The Béziers direction agrees well with the, rather numerous, contemporaneous data and with the French secular variation master curve that shows a relatively fast declination decrease between 800-700 and 400 BCE.…”

“…The main limitation is the inhomogeneous spatio-temporal distribution of archaeomagnetic data at the global but also regional scales. Data are for example rare in Italy in the first millennium BCE (e.g., Tema et al, 2006;Tema and Lanos, 2020) or scarce in West Europe before 800 BCE (e.g., Hervé et al, 2013aHervé et al, , 2013bMolina-Cardin et al, 2018;Palencia-Ortas et al, 2017). In this article, we present three new directional data and six new intensity data from France and South Italy dated between the 13 th and the 4 th centuries BCE.…”

First Full Vector Archeomagnetic Data From Northern Mexico

“…They can be used to define the temporal and spatial variation of the magnetic field worldwide. Another way to describe secular variation is to construct local reference curves for a given area in direction and/or intensity (e.g., Hervé et al., 2017; Kovacheva et al., 2014; Molina‐Cardın et al., 2018; Tema & Lanos, 2021).…”

“…is to construct local reference curves for a given area in direction and/or intensity (e.g., Hervé et al, 2017;Kovacheva et al, 2014;Molina-Cardın et al, 2018;Tema & Lanos, 2021).…”