Fruit and seed biomineralization and its effect on preservation

Mineralised fruits and seeds are frequently found in archaeological sediments but their chemical nature has not been often examined. The nature and the origin of these archaeobotanical remains have to be investigated to understand their taphonomic history. Fruits or seeds can be mineralised not only by replacement mineralisation but also by biomineralisation during the plant life. The mineral components of three fossil fruits sampled on the Pleistocene site of Dmanisi were analysed and compared with their modern analogues. Analyses were carried out by means of an environmental scanning electron microscope, equipped with an energy dispersive X-ray device and by means of a Fourier transform infrared spectrometer. Biogenic carbonates and/or biogenic silica were identified in the fossil and modern fruits of some taxa. Comparison between fossil and modern specimens has shown that molecular reorganisation occurred in carbonate and in biogenic silica during fossilisation, through diagenetic processes. The resulting stable mineral structures confer an exceptional preservation to fruits in sediments. Taking into account these taphonomic specificities (transformation and differential preservation), the chronological and palaeoenvironmental aspects of the mineralised fruits are discussed.     

Hunter–gatherer foraging ranges, migrations, and travel in the middle Holocene Baikal region of Siberia: Insights from carbon and nitrogen stable isotope signatures

Foraging ranges, migrations, and travel among Middle Holocene hunter–gatherers in the Baikal region of Siberia are examined based on carbon and nitrogen stable isotope signatures obtained from 350 human and 203 faunal bone samples. The human materials represent Early Neolithic (8000–6800 cal BP), Late Neolithic (6000–5000 cal BP), and Early Bronze Age periods (∼5000–4000 cal BP) and come from the following four smaller areas of the broader region: the Angara and upper Lena valleys, Little Sea of Baikal’s northwest coast, and southwest Baikal. Forager diets from each area occupy their own distinct position within the stable isotope spectrum. This suggests that foraging ranges were not as large as expected given the distances involved and the lack of geographic obstacles between the micro-regions. All examined individuals followed a similar subsistence strategy: harvesting game and local fishes, and on Lake Baikal also the seal, and to a more limited extent, plant foods. Although well established in their home areas, exchange networks with the other micro-regions appear asymmetrical both in time and direction: more travel and contacts between some micro-regions and less between others. The Angara valley seems to be the only area with the possibility of a temporal change in the foraging strategy from more fishing during the Early Neolithic to more ungulate hunting during the Late Neolithic–Early Bronze Age. However, the shift in stable isotope values suggesting this change can be viewed also as evidence of climate change affecting primary productivity of the Baikal–Angara freshwater system.     

La Crise des intellectuels français: aspects historiques et retombées historiographiques

Les intellectuels français ont-ils connu, à la fin du siècle dernier, une crise ? Ce diagnostic vint du milieu intellectuel lui-même, qui, affaibli par la perte de crédibilité des systèmes de pensée associés aux confrontations idéologiques de la guerre froide, voyait dans la montée en puissance d'une culture médiatique de nouveaux leaders d'opinion brouillant les contours de la mouvance culturelle jusque-là essentiellement constituée d'hommes et de femmes venus de la sphère de l'imprimé. D'une certaine façon, le pathos l'a en effet emporté sur le logos, discours construit et analyse argumentée des problèmes posés à une société. A cet égard, la crise des intellectuels est à la fois un reflet et un accélérateur de la crise des démocraties représentatives, dont le fondement était l'examen raisonné et la concurrence raisonnable des possibles et dont le fonctionnement risque d'être parasité par les palpitations successives d'opinions publiques en proie à des émotions liées aux bruits et aux fureurs de la culture médiatique, devenue elle-même, de plus en plus, une culture-monde.