1. Archeomagnetic intensity investigations of French medieval ceramic workshops: Contribution to regional field modeling and archeointensity-based dating
- Author
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S. Regnard, Agnès Genevey, Yves Gallet, Sébastien Jesset, Philip W. Livermore, Annie Lefèvre, N. Mahé-Hourlier, Erwan Thébault, Alexandre Fournier, E. Marot, Laboratoire d'Archéologie Moléculaire et Structurale (LAMS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), University of Leeds, Pôle d'Archéologie Ville d'Orléans, Institut national de recherches archéologiques préventives (Inrap), Centre Michel de Boüard - Centre de recherches archéologiques et historiques anciennes et médiévales (CRAHAM), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Service d'archéologie préventive de Bourges Plus, Ministère de la Culture et de la Communication (MCC), Centre de Recherches Archéologiques du Vexin Français (CRAVF), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), School of Earth & Environment, University of Leeds, Institut national de recherches archéologiques préventives, Centre archéologique de La Courneuve (Inrap, La Courneuve), and Inrap, Passy - Centre de recherches archéologiques de Passy
- Subjects
010504 meteorology & atmospheric sciences ,Physics and Astronomy (miscellaneous) ,Thermoremanent magnetization ,[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] ,Posterior probability ,Western Europe ,010502 geochemistry & geophysics ,01 natural sciences ,law.invention ,law ,Range (statistics) ,Medieval period ,Radiocarbon dating ,Bootstrapping (statistics) ,0105 earth and related environmental sciences ,Astronomy and Astrophysics ,Geodesy ,Field intensity modeling ,Archeointensity dating ,Geophysics ,Amplitude ,Space and Planetary Science ,Pottery ,Archeointensity ,Intensity (heat transfer) ,Geology - Abstract
International audience; Seven new archeointensity data are obtained through the analysis of groups of pottery and kiln fragments from ceramic workshops unearthed in France, precisely dated from the High Middle Ages. The measurements are carried out using the Triaxe magnetometer, following a dedicated experimental protocol that takes into account the effects of anisotropy and cooling rate (CR) on thermoremanent magnetization acquisition. The new data are consistent with the evolution of intensity variations described by our previous data obtained in France and Northern Italy, which display between the 5th and 10th c. a pronounced camel-back shape. In particular, they provide supporting evidence of an intensity minimum that occurred around the transition between the 7th and 8th century. These data, combined with a selection of previously published results within a 700 km radius of Beaune and re-examined based on CR correction, formed the basis of new regional mean intensity variation curves based on two independent modeling approaches. The first algorithm developed by Thébault and Gallet (2010) based on bootstrapping and now irregularly spaced knots according to the data distribution gives rather smooth intensity variations, while the second approach proposed by Livermore et al (2018) based on a transdimensional Bayesian technique shows more abrupt variations with sometimes stronger amplitudes. We explore the dating potential of these two variations curves, which have an unprecedented resolution, by studying two medieval pottery workshops. Six fragment groups (three per workshop) are analyzed using the Triaxe protocol, providing mean archeointensity values for each of the two sites. Two different procedures are used for their dating, either by comparing the intensity value to be dated with the reference intensity variation curves obtained from the two modeling techniques or by analyzing the marginal posterior probability distribution of the age values derived from the method of Livermore et al (2018). For France, the two techniques yield very similar results. The archeointensity dating results combined with archeological arguments and radiocarbon data, make it possible to better constrain the age of the end of activity of the two workshops. Archeointensity investigation of displaced materials thus appears as an effective means to obtain original chronological constraints on the age of their production, paving the way for a wide range of complementary research on Medieval pottery.
- Published
- 2021
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