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

Archeomagnetism allows one to track the temporal evolution in direction and intensity of the Earth's magnetic field over the past few millennia, mainly from archeological material baked during their manufacturing or use. Its applications are of interest to both geomagnetism, which investigates the behavior and origin of the geomagnetic field, and archeology, which relies on curves of the magnetic field direction and/or intensity secular variation for dating purposes. Recent archeomagnetic results also suggest a connection between the geomagnetic field and climatic changes during the Holocene. In this article, we also discuss the acquisition of new archeointensity data obtained from potsherds found in the Etruscan site of La Castellina (Italy) and in Vanves (France), respectively dated to the VIIth century BC and to the IXth century AD.

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Annie Lefevre et Nicole Meyer, Die Keramiklampen der städtischen Grabungen zu Saint-Denis. Etwa 200 Lampen oder Bruchstucke davon förderten die jungsten städtischen Grabungen, die in der Umgebung der Basilika zu Saint Denis durchgefuhrt wurde, zutage. Ihr Entstehungszeitraum reicht von 8. Jd. bis zu Beginn des 17. Jd. Die quantitative Bedeutung dieser Sammlung rechtfertigte diese Voruntersuchung in Erwartung der Veröffentlichung des Ausgrabungsberichts. Die morphologische Analyse ermöglichte es, acht ungleichmäßig vertretene Gattungen zu bestimmen. Parallel dazu konnte die technologische Untersuchung die Sammlung in sechs Klassen einordnen. Die Synthese dieser zwei komplementären Untersuchungsmethoden fiihrt zur Bestimmung von vierzehn Typen, deren Zusammenhang durch die Analyse ihrer chronologischen Streuung bekräftigt wird. Die Datierung der Lampen kann einerseits durch die technologische Gegenuberstellung mit der Gesamtheit der Keramikfunde des Ausgrabungsorts versucht werden ; andererseits kann sie durch die Analyse ihres stratigraphischen Ursprungs und der ihr zugeordneten datierten Gegenstände sowie durch die Berucksichtigung der historischen topographischen Gegebenheiten des Ausgrabungsorts verfeinert werden.