New archeointensity data from French Early Medieval pottery production (6th–10th century AD). Tracing 1500 years of geomagnetic field intensity variations in Western Europe
Agnès Genevey|Yves Gallet|Sébastien Jesset|Erwan Thébault|Jérôme Bouillon|Annie Lefèvre|Maxime Le Goff
Nineteen new archeointensity results were obtained from the analysis of groups French pottery fragments dated to Early Middle Ages (6th 10th centuries AD). They are several medieval ceramic production sites, excavated mainly in Saran (Central France), and their precise dating was established based on typo-chronological characteristics. Intensity measurements performed using Triaxe protocol, which takes into account effects intensity determinations both thermoremanent magnetization anisotropy cooling rate. analyses also carried out modern produced at during an experimental firing. The show very good agreement with geomagnetic field directly measured inside around kiln, thus reasserting reliability protocol relevance quality criteria used. further demonstrate potential for archeomagnetism. allow a coherent description variations Western Europe Medieval period, until now poorly documented. significant increase 6th century AD, high values 7th 9th century, minimum small amplitude transition between 8th finally important decrease beginning 11th century. Together published available within radius 700 km Paris, data used compute master curve European over past 1500 years. This clearly exhibits five maxima: middle 12th second part 14th 17th AD. Some these peaks smoothed, or nearly absent when selection is extended 1250 Paris. apparent regularity occurrence maxima, recurrence ∼250 years, particularly intriguing might reflect characteristic secular variation, least Europe. It requires investigation particular acquisition older periods.
Physics of the Earth and Planetary Interiors|HAL (Le Centre pour la Communication Scientifique Directe)|HAL (Le Centre pour la Communication Scientifique Directe)