Une enceinte de type ring fort du Bronze final et un enclos d’habitat du premier âge du Fer à Mondeville (Calvados)

International audienceThe excavation at Mondeville « Rue Nicéphore Nièpce » located in the Caen plain has led to the unexpected discovery of a Protohistoric site with two chronological phases. A double circular enclosure, dating to the end of the Bronze Age is of major interest for landscape studies and ongoing research on settlements for this period. A second settlement enclosure dating to Early Iron Age sheds new light on this densely populated area during Late Prehistory. The Late Bronze Age enclosure comprises two incomplete curved parallel ditches made up of oval shaped segments of varying length. Two breaks in the ditches provide an entrance to the south-west and the south-east. The excavation covered a 2750 m² area of a site estimated at almost 6 000 m². The outer diameter of the enclosure is 90 m. As the site has two phases, it has not been possible to attribute features to this first phase due to the lack of datable artefacts. The fill of the two ditches, specifically the lower and intermediary levels, are very similar but fail to give any indication as to the location of a bank. The upper fill of the inner ditch is an anthropogenic layer containing artefacts dating to Hallstatt D that indicate that the ditch was levelled off during the site's later phase. The large deposits of mainly cattle bones in the ditches has shed light on meat consumption on the site, with the slaughter of significant numbers of young animals. The high proportion of skulls some of which were exposed and the high mni indicate 'extraordinary' 'consumption' during specific manifestations. Another interesting aspect is the presence of some human bone in the fill with the alinement of the bones of five incomplete skeletons that showed marks of post-mortem manipulation.The radiocarbon dates of three samples of animal bone from the lower fill and human bone indicate 1220 to 907 BC. The pottery is similar to the Plain Ware and Decorated Ware phases from Manche-Mer-du-Nord sites dating to the middle and late phases of the Late Bronze Age.The Mondeville site plan is similar to the Late Bronze Age monumental circular enclosures or ring forts of Great Britain. The Normandy ring forts of Cagny (Calvados), Malleville-sur-le-Bec (Eure) and Lamballe « La Tourelle » (Côtes-d'Armor) in Brittany are the only French examples. The radiocarbon dates of these sites and their British counterparts (Mucking « North Ring », Springfield Lyons, Thwing, Grimthorpe and Tintore) indicate that these enclosures were in use from the 13th to the 9th century BC.After several centuries, the Late Bronze Age ditches were two thirds filled in leaving a slight depression in the landscape obviously still visible during the Iron Age. The Hallstattian enclosure partially follows its Late Bronze age counterpart with a similar orientation of its entrance. The ditch is finally filled in by domestic and combustion waste from the Iron Age site.The Hallstatt D enclosure comprises two perpendicular ditches forming two sides of a rectangle. The enclosed area with its western entrance has an estimated surface area of 5700 m² accessible. The pottery dates a number of features to the Hallstatt D, which include a feature to collect water, storage pits or extraction pits. These features have provided diverse artefacts characterising the domestic and agro-pastoral activities of the site. The zooarchaeological study reveals that meat and by products were mainly obtained from cattle rearing. The pottery finds date the enclosure dates to the Hallstatt D1/D2 phase and indicate that it remained in use until the Hallstatt D3. A Couville type amorican socketed axe, which constitutes a particularly important find in a domestic context, was retrieved from the enclosure ditch. The site also includes five graves, three date to the Hallstatt period and two to the Middle La Tène phase. The two La Tène graves are located in the ditch fill and show that the site was still in use during this later period when a new enclosure was built to the south of the original site.The enclosure's layout is typical of enclosed settlements built during the Hallstatt D as has been observed in the Caen plain. The site encloses more than a hectare, which is significantly larger than contemporary sites. It is therefore tempting to see a link between the enclosure's size and the high status of the earlier Bronze Age enclosure. Another important fact about the site is that it is located in an area densely occupied at the end of the Early Iron Age.La fouille préventive réalisée à Mondeville « 31 rue Nicéphore Niepce » a permis d'identifier deux phases d'occupation, l'une datée du Bronze final et l'autre du premier âge du Fer. La première est matérialisée par un double dispositif fossoyé de plan circulaire, partiellement connue dans l'emprise. Les fossés ont livré des rejets de faune et un important dépôt, mettant en évidence un spectre faunique dominé par le boeuf et offrant des observations intéressantes sur des pratiques de consommation « extraordinaires ». Une autre particularité concerne la présence d'ossements humains isolés au sein des fossés et l'alignement de restes de corps humains, ayant fait l'objet de manipulations post-sépulcrales. Cette enceinte, datée entre 1220 et 907 avant notre ère sur la base de cinq analyses 14C, est à rapprocher avec les enceintes circulaires monumentales ou ring forts, connus en Grande-Bretagne pour le Bronze final et identifiés en Normandie à Cagny et Malleville-sur-le-Bec. Le statut de ce site demeure à ce jour énigmatique, tout comme son rôle dans le panel des formes d'habitats pour les phases finales de l'âge du Bronze.L'enclos du premier âge du Fer est formé par deux fossés rectilignes, composant un plan probablement quadrilatéral mais incomplet. Parmi les vestiges internes, une structure de captage d'eau et des fosses à vocation de stockage ou d'extraction témoignent du caractère domestique et agro-pastoral du site. La céramique permet d'avancer une datation du Hallstatt moyen pour la fondation de cet enclos, avec une perduration au Hallstatt final. Sa configuration s'intègre parfaitement dans la vague d'apparition des premières formes d'habitat encloses au cours du Hallstatt moyen/final, telle que reconnue à ce jour dans la plaine de Caen