Landscape change and archaeological settlements in the lower Danube valley and delta from early Neolithic to Chalcolithic time: A review

International audiencePalaeogeographic changes of the North Black Sea area during Early to Middle Holocene (i.e. 12e4 ka BP) is of crucial interest in the understanding of the spread of the Neolithic to central and western Europe. It is also a good method to develop a framework for Pre- and Proto-historic societal adaptation to environmental changes. This paper describes Black Sea coastal geomorphological changes associated with sea level rise, delta progradation and delta lobe shifts modifying the living conditions and habitability in the Danube delta during Neolithic to Chalcolithic time. An archaeological and palaeoenvironmental chronological framework allows comparison between environmental and social data. The rhythms of these changes are discussed in the light of spatial changes in settlements. The Neolithic to Chalcolithic transition (i.e. Hamangia, Boian and Gumelnit¸ a) shows rapid adaptation to geographical conditions. The Early Neolithic gap in the Dobroudja is potentially the result of a taphonomic bias related to coastal position change in a context of a rapid flooding event

Aftermath of the flooding : geomorphological evolution of the Danube delta after the black sea-mediterranean reconnection and its implications on eneolithic settlements

International audienceIn this article we document the evolution of the internal area of the Danube Delta (i.e. the blocked delta) starting from the geo-archaeological and geomorphological investigations performed at Mila 23 district, following the discovery of the oldest human settlement in the Delta. The in-site and out-site field work and coring allowed us to specify the delta's early stages of evolution from 5600 to 4000 CAL BC. During this period, the site evolves as a freshwater bay-head delta flowing into a huge lagoon isolated from the open sea by Letea-Caraorman spits. The rapid sedimentation rate in the lagoon is interpreted as a response to base-level rise and overflooding as a result of humid conditions during 6-5 ky RCC, leading to the partial submersion of the site and probably to its abandonment around 4450 CAL BC

Preparation and characterization of La0.8_{0.8}Ca0.2_{0.2}Fe0.8_{0.8}Co0.2_{0.2}O3−δ_{3-δ} as a new air electrode material for solid oxide cells

Preparation and characterization of La0.8Ca0.2Fe0.8Co0.2O3-δ as a new air electrode material for solid oxide cellsMario Micu-Budisteanu1, Christian Berger2, Edith Bucher1, Christian Lenser3, Norbert H. Menzler3, Werner Sitte11 Chair of Physical Chemistry, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria2 Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany3 Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research – Materials Synthesis and Processing (IEK-1), 52425 Jülich, GermanyPerovskites from the series (La,Sr)(Co,Fe)O3-δ are mixed ionic and electronic conductors that are suitable for a broad variety of possible applications, with cathodes for solid oxide fuel cells (SOFCs), anodes for solid oxide electrolyser cells (SOECs), electrochemical gas sensors and catalysts being the most promising fields of application. However, due to long-term stability issues, current research efforts are directed towards development of alternative Sr-free materials. Recently, high electronic- and good ionic conductivities, as well as exceptionally fast oxygen exchange kinetics were demonstrated for La0.8Ca0.2FeO3-δ (LCF82). In the present work, substitution of this material with cobalt is investigated with the aim to further improve sintering activity and electronic conductivity. Therefore, La0.8Ca0.2Fe0.8Co0.2O3-δ (LCFC8282) was synthesized using a sol-gel method. XRD confirmed that the material is single phase. Thermal expansion coefficients (TEC) were determined as a function of oxygen partial pressure (1×10-3 ≤ pO2/bar ≤ 1) and temperature (600 ≤ T/°C ≤ 1000). In comparison of LCF82 with LCFC8282, the TEC of the Co-substituted material is slightly higher with values of 19-23×10- 6 K-1. The electronic conductivity of LCFC8282 is in the range of 128 ≤ S cm-1 ≤ 145 at 600 ≤ T/°C ≤ 800 and pO2=0.1 bar and thus higher than that of LCF82 (~110 S cm-1). First results on the oxygen exchange kinetics of LCF8282 show high activity towards oxygen reduction

Géohistoire du delta du Danube : l'apport des archives communistes pour appréhender les temporalités d'artificialisation des écosystèmes

International audienc

Après le Déluge : évolution géomorphologique du delta du Danube après la reconnexion Mer Noire - Méditerranée et ses implications sur le peuplement énéolithique / Chalcolithique

Dans ce travail, l’évolution de la zone interne du delta du Danube est appréhendée à partir de travaux géoarchéologiques et géomorphologiques réalisés dans le district de Mila 23, suite à la découverte de la plus vieille occupation humaine (énéolithique/chalcolithique) du delta dans les années 90. Les travaux sur site et hors site ont permis de préciser les stades précoces de l’évolution du delta entre 5 600 et 4 000 ans cal. av. J.-C. Celui-ci évolue comme un delta lagunaire en eau douce, s’épandant dans un large lagon séparé de la mer par la ride de Letea-Caraorman. La remontée rapide du niveau lagunaire, sous l’effet de la remontée eustatique et peut-être d’une surcote liée à un événement humide, ont conduit à une submersion partielle du site et probablement à son abandon vers 4 450 ans cal. av. J.-C.In this work, we document the evolution of the upper Danube delta (i.e. blocked delta) using archaeological, geomorphological and geoarchaeological approaches, after the discovery, in the 90’s, of the oldest human settlement (Eneolithic/Chalcolithic) close to Mila 23 district. In-site and out-site fieldwork allows us to refine the Danube delta early evolution from 5,600 to 4,000 cal. yr BC. During this period, it functions like a fresh bayhead delta, flowing into a huge lagoon isolated from the open sea by the Letea-Caraorman spit. Then, lagoon water level rose rapidly due to an eustatic rise, and possibly from an unusual highstand of sealevel resulting from wet conditions. The settlement was then partially flooded and abandoned around 4,450 cal. yr BC