Sur l'évolution géodynamique du Marquenterre (Basse-Somme) à l'HoIocène et durant le Weichsèlien ancien

International audienc

Géologie, sédimentologie et microfaune de la butte d'Ar Vein située à 30 km de Penmac'h par 105 m de fond

National audienc

Alternances de sédimentation marine et continentale durant l'Holocène en Plaine maritime picarde

In a type-profile of soil of the Picardy Coastal Plain, the combination of the Carbon 14 dates of the peat levels and of the identification of the Foraminifers permits to separate marine, brackish, continental influences on the sedimentation and to specify the different phases of it, in correlation with the evolution of the sea-level. Calcium carbonate percentages of the successive layers permit to appreciate homogeneity, diversity, evolution of the sediments. Values of Nitrogen and Carbon give furthermore basic information about the organic components. Comparison of borings emphasizes the predominance of the marine or continental component, according to the geographic position of the profile.Dans un profil-type de la Plaine maritime picarde, la combinaison des datations C14 des tourbes et des déterminations de Foraminifères permettent de séparer les influences marines, saumâtres et continentales sur la sédimentation et d'en préciser les différentes phases, en corrélation avec l'évolution du niveau marin. Les pourcentages de calcaire des horizons successifs permettent d'apprécier l'homogénéité, la diversité et l'évolution des sédiments, tandis que les teneurs en azote et en carbone fournissent, en plus, des données de base sur le matériel organique. La comparaison de sondages montre la prédominance des composantes marines ou continentales suivant la position géographique du profilLefèvre P., Rouvillois A., Gaffet M. A., Bignot G. Alternances de sédimentation marine et continentale durant l'Holocène en Plaine maritime picarde. In: Bulletin de l'Association française pour l'étude du quaternaire, vol. 17, n°1-2, 1980. pp. 25-33

Recherches sur les foraminifères actuels des côtes françaises de la Manche et de la mer du Nord

National audienc

Describing a Unique Urban Culture: Ibadi Settlements of North Africa

Abstract. This paper examines the urban structure and architecture of the North African regions, which are characterised by the historical presence of Ibadism. This topic has a definite cultural frame, albeit with some differences across three geographical areas located in the Mediterranean Maghreb: the Island of Djerba in Tunisia, the region of Mzab in Algeria, and the Djabal Nafusa mountains in Western Libya. Although similar configurations can be found in different parts of the Mediterranean territories, in these particular regions, the need for protec-tion and defence, such as the balanced use of natural resources, has played an emblematic role. From the 10th century onwards, in fact, Ibadi communities chose the hard conditions of these lands to preserve their cultural identity, even at the cost of their isolation. Guided by the desert climate and scarcity of natural resources, these peoples developed specific urban solutions, architectural forms and construction traditions. The objective of this research is to define and compare the main facets of settlements and architectural forms, with the purpose of understanding and verifying the cultural continuity