Roman Rhine settlement dynamics evidenced by coin distribution in a fluvial environment (Oedenburg,Upper Rhine,France)

On the basis of archaeological and alluvial records, this paper presents the first spatial analysis of artefacts in relation to the evolution of the Rhine River, at the Gallo-Roman site of Oedenburg, during the first four centuries AD. The dataset consisted of several thousand Roman artefacts found by pedestrian prospecting over the last twenty years, over half of which were coins. This dataset was used together with high-resolution topography and geomagnetic mapping, to reconstruct settlement evolution, both on the terrace and in the floodplain. A comprehensive monetary chart has been compiled for the Oedenburg site, which highlights four major phases of settlement. These results provide a possible causal link connecting historical factors and alluvial events with intra-site evolution. Therefore, while changes observed during Phases I (until AD 68), II (AD 69 to AD 180) and III (AD 180 to AD 295) seem largely related to historical and societal events, Phase IV (AD 295 to AD 402) shows patterns of abandonment of the lower part of the floodplain that may well be related to an unusually humid period in the fourth century. These results are set in a broader context, from the Rhine catchment area to the Alps, and are in agreement with the wet conditions also documented in alluvial, lacustrine, geomorphological and palynological records in Germany (Lahn River, Lake Constance, Lake Nussbaumen, Kaisersthul area and the Black Forest). Studying the intra-site spatial distribution of artefacts with high temporal constraints, at a long-lived site with contrasted topography, opens new avenues for the detection of discreet events such as a higher water table, affecting only the lower zone.     

Diversification,Intensification and Specialization: Changing Land Use in Western Africa from 1800 BC to AD 1500

Journal of World Prehistory - Many societal and environmental changes occurred between the 2nd millennium BC and the middle of the 2nd millennium AD in western Africa. Key amongst these were...     

Middle Stone Age Bifacial Technology and Pressure Flaking at the MIS 3 Site of Toumboura III,Eastern Senegal

African Archaeological Review - Over the past decade, the increasing wealth of new archaeological data on the Middle Stone Age (MSA) in Senegal and Mali has broadened our understanding of...     

Crystallographic and structural transformations of sedimentary chalcedony in flint upon heat treatment

The early occurrence of intentional heat treatment of silica rocks has recently become a key element in the discussion about the cultural modernity of prehistoric populations. Lithic vestiges are the only sources that remain of this process and the understanding of the material’s properties and transformations are essential for reconstructing the conditions and parameters applied during heat treatment. Several models of the structural transformations upon heating have been proposed in the current literature. These models are often contradictory and do not account for the most recent structural and mineralogical data on chalcedony. In order to propose a new model, we elaborated an experimental procedure and applied different techniques involving infrared spectroscopy, solid state NMR, X-ray diffraction and electron microscopy. The results show that the major transformation to happen is the loss of silanole (SiOH) and the creation of new Si-O-Si bonds according to the reaction: Si?OH HO-Si → Si-O-Si + H₂O. This reaction starts between 200 °C and 300 °C and causes an increase in the hardness of the rocks. The maximal annealing temperature and the ramp rate are the functions of the ability of the structure to evacuate newly created H₂O and depend on the size of the specimen and the volume of its porosity. These results also show that the annealing duration at maximum temperature can be relatively short (<50 min) for a sufficiently large amount of transformation to be accomplished.