Enhancing the European Archaeointensity Database: New Data From Italy
Résumé
Global geomagnetic models using archaeomagnetic data can offer important insights in to geomagnetic field evolution and core mantle boundary processes. However, in order to provide a complete field description it is necessary to have many data giving good spatial and temporal coverage. Due mainly to experimental difficulties there are many more directional data than intensity data, and whilst data coverage is reasonable for some locations it is recognised that many more high quality data are still needed. Here we present results from two Italian sites: a Roman Amphorae workshop (dated to be between 200 BC and 100 AD), Albinia, Tuscany, and from a 7th Century BC site at Incoronata, Pisticii, Basilicata. The classical Thellier technique was used with anisotropy of thermal remanence and cooling rate corrections. At Albinia, samples were taken from five kilns and from the base of 39 amphorae. The mean archaeointensity per kiln / the amphorae range from 62 to 70 microT. This variation may reflect them being of differing ages however it could also reflect the limitations of the experimental protocol and/or samples. Thus it is desirable that a number of archaeointensity data per time interval are obtained in order to reliably determine the past variations of the geomagnetic field. At Incoronata samples were drilled from 39 bricks. The mean archaeointensity of 85 microT obtained for the older Incoronata bricks is consistent with the increase in field intensity seen going back through the first millennia BC in other regions such as Mesopotamia.