Search

Early inhabitants along the hyperarid coastal Atacama Desert in northern Chile developed resilience strategies over 12,000 years, allowing these communities to effectively adapt to this extreme environment, including the impact of giant earthquakes and tsunamis. Here, we provide geoarchaeological evidence revealing a major tsunamigenic earthquake that severely affected prehistoric hunter-gatherer-fisher communities ~3800 years ago, causing an exceptional social disruption reflected in contemporary changes in archaeological sites and triggering resilient strategies along these coasts. Together with tsunami modeling results, we suggest that this event resulted from a ~1000-km-long megathrust rupture along the subduction contact of the Nazca and South American plates, highlighting the possibility of M w ~9.5 tsunamigenic earthquakes in northern Chile, one of the major seismic gaps of the planet. This emphasizes the necessity to account for long temporal scales to better understand the variability, social effects, and human responses favoring resilience to socionatural disasters.

Pleistocene deposits exposed along the coast of the Medoc area, south-west France, represent valuable palaeoenvironmental archives that have been the subject of extensive work in the past few decades. To further understand the palaeoenvironmental history and sedimentary dynamics of these deposits, a detailed lithostratigraphic study was performed on a series of new sections. Additionally, new chronological data were obtained from the combination of luminescence (OSL, IR-RF) and electron spin resonance (ESR) dating of quartz and feldspar grains (Kreutzer et al., 2018). The investigated sections comprise estuarine, lacustrine and peaty deposits (Negade Formation, Argiles du Gurp Formation), aeolian sands (Sables du Gurp Formation) and colluvial units (Gres de l'Amelie Formation). The Argiles du Gurp Formation, in which many remains of Palaeoloxodon antiquus were found, support the hypothesis of a progressive replacement of a tide-inluenced marsh by a peaty fresh-water pond during the Holsteinian Interglacial (MIS 11). IR-RF dating of green estuarine clays at L’Amelie, in the northernmost part of the investigated area, strongly suggests that they do not belong to the Argile du Gurp Formation, but were deposited during the MIS 9 sea level highstand. The estuarine deposits are overlain by sandsheets (Sables du Gurp Formation) dated to MIS 10 and MIS 8 at Pointe de la Negade in the southern part of the study area, and to MIS 8 at L’Amelie. Syngenetic frost cracks testify to a periglacial depositional environment. Regional studies show that the Sables du Gurp Formation is a local equivalent of the Sables des Landes Formation, and corresponds to the oldest aeolian phase recorded in south-west France so far. Colluvial material (Gres de l'Amelie Formation) dated to the Weichselian pleni-glacial (MIS 2) ill small palaeo-valleys incised in the Sables du Gurp Formation. Holocene coastal dunes cover the whole sequence.

A previously undocumented type of wetland is described from the Atacama Desert in northern Chile (3000 m above sea level), sustained exclusively by direct precipitation and perched above the regional water table. Geomorphological mapping, pedostratigraphy, geochemistry, and analysis of contemporary vegetation is used to understand wetland formation and dynamics during historical and present time periods. The paleowetland deposits overlie a Miocene tuff that acts as an impermeable barrier to water transfer and creates conditions for local shallow ground water. These deposits include several paleosols that were formed during periods when precipitation increased regionally at 7755–7300, 1270, 545, and 400–300 cal yr BP. The similarity in timing with other palaeohydrological records for the Atacama implies that paleosols from this wetland are proxies for reconstructing past changes in local and regional hydrological cycle. Archaeological investigations have revealed the presence of two small farms from the Late Intermediate period, i.e., during the earliest wetter phase represented by the paleosols. Both farms are located near the paleowetland deposits, which suggests that local inhabitants exploited these water sources during late pre-Hispanic times. Results of this study improve knowledge of settlement patterns during this and earlier cultural periods.

Le gisement de plein air de Mirande 2 a été récemment découvert sur la commune de Vaïssac (Tarn-et-Garonne), à une centaine de mètres du site de Mirande 1 fouillé entre 1971 et 1976 par R. Guicharnaud à Nègrepelisse. Cette opération de sondage préventif a permis d’évaluer les potentialités du site, d’en proposer une contextualisation géologique précise et d’exhumer les divers éléments de diagnose présentés ici. Mirande 2 est implanté sur un léger replat en rive gauche de l’Aveyron. Les trois secteurs de fouille (Tranchée Sud, Coupe Nord et Sondage) ont exclusivement livré des vestiges lithiques (silex et quartz) dont les caractéristiques typo-technologiques sont constantes d’une zone à l’autre et forment un ensemble cohérent sur le plan chronoculturel. Les premières observations archéostratigraphiques indiquent l’existence d’une concentration principale plus ou moins dilatée selon les secteurs. Les vestiges, dont les caractéristiques technotypologiques permettent d’attribuer l’ensemble au Badegoulien, se répartissent en différents types de supports et matières premières. Quelques blocs de trachyte façonnés et des galets de quartz débités proviennent vraisemblablement de la paléo-terrasse sur laquelle se sont installés les groupes humains. Les quartz sont présents sous la forme de macro-outils ou débités pour obtenir des éclats. L’essentiel des silex abandonnés sur le site provient des terrasses de la Vère et de l’Aveyron. Quelques indices tendraient également à montrer un apport de volumes en silex allochtones sur près de 100 km depuis le nord. En revanche, les autres matériaux allochtones sont présents sous la forme d’outils, signant vraisemblablement une fin de cycle fonctionnel. Du point de vue des supports d’outils à vocation domestique, on note une double composante. Des grattoirs, outils multiples et pièces à retouches latérales sont réalisés sur lame et éclats laminaires. Pour cette composante, et en l’état de l’analyse, l’hypothèse de deux schémas opératoires peut être proposée : une production laminaire cintrée et un débitage de supports envahissants sur face large. D’autres outils (racloirs, raclettes) sont réalisés sur éclats résultant de diverses chaînes opératoires parfois autonomes. Les microlithes sont composés de lamelles et micro-lamelles à dos de différents types et dont les supports sont produits à partir de rognons et éclats selon différentes modalités. Si le gisement de Mirande 2 constitue un nouveau témoignage d’occupations de plein air sur la paléo-terrasse de l’Aveyron, à proximité de sa confluence avec le Gouyré, il offre avant tout l’un des premiers jalons badegouliens entre Languedoc et Quercy, dans une région où il était peu connu jusqu’alors. The recently discovered open-air site of Mirande 2 (Vaïssac, Tarn-et Garonne) lies on a gentle incline of the left bank of the Aveyron River approximately 100 metres from the site of Mirande 1 (Nègrepelisse, Tarn-et-Garonne), which was excavated between 1971 and 1976 by R. Guicharnaud. A test-pit carried out during rescue work evaluated the site’s potential, provided important geological and produced diagnostic archaeological material. The three excavated sectors (South Trench, North Section and Test-Pit) preserved only lithic material (flint and quartz), whose typo-technological composition evinces a chrono-culturally coherent assemblage. Initial archaeo-stratigraphic information indicates a single concentration of archaeological material that varies in thickness by sector. Attributable to the Badegoulian, the lithic assemblage comprises various blanks and multiple types of raw materials. Several shaped trachyte blocks and quartz pebbles, exploited for the production of heavy-duty tools and flakes, likely derive from the paleo-terrace occupied by the human groups. While the majority of the flint artefacts come from the terraces of the Vère and Aveyron Rivers, a limited quantity of non-local raw materials were introduced from sources some 100 km to the north. These latter artefacts are found uniquely as tools that were likely discarded at the end of their use-lives. Two types of domestic tool blanks were identified ; endscrapers, combination tools and laterally retouched pieces on blades and elongated flakes alongside scrapers and raclettes on flakes produced according to different, sometimes independent chaînes opératoires. In terms of the blade and elongated flake component, our preliminary analysis suggests blanks to have been detached from either a wide surface or from wedge-shaped cores. Finally, microliths are represented by different types of backed micro-bladelets on blanks produced from nodules and flakes. In addition to Mirande 2 being a new open-air occupation on the paleo-terraces of the Aveyron River near its confluence with the Gouyré, it also amongst the first evidence for the Badegoulian between the Lanquedoc and Quercy regions in an area where this culture remained poorly documented.

Découverte en 1990, la grotte-abri de Peyrazet (Creysse, Lot, France) se situe dans le Haut-Quercy en bordure du causse de Martel, à quelques centaines de mètres du cours actuel de la Dordogne. Les fouilles menées depuis 2008 livrent une archéoséquence du Tardiglaciaire qui permet de combler certaines lacunes documentaires régionales et plus largement du Sud-Ouest de la France. Au Magdalénien supérieur succède un niveau ayant donné des indices d’un Azilien sensu lato stratigraphiquement séparé du Laborien, ensemble supérieur qui fait l’objet de cet article. Jusqu’alors ce technocomplexe de la fin du Pléistocène et des débuts de l’Holocène demeurait mal connu dans la région. En effet, seuls des travaux anciens menés dans deux gisements permettaient de noter sa présence en Quercy. La découverte d’un ensemble laborien récent (ou Épilaborien) à Peyrazet est l’occasion de conduire une étude collective des divers vestiges dans un cadre archéostratigraphique mieux maîtrisé. L’analyse géoarchéologique met en évidence l’action conjointe du ruissellement et de l’éboulisation comme principaux responsables de la mise en place des dépôts. Dans la partie S-O du site, un lithofaciès de remaniement indique une bioturbation importante en lien avec le creusement de terriers. Bien que leur origine ne soit pas liée aux activités humaines, les rongeurs, les oiseaux, les poissons et les mésomammifères (excepté le lièvre) apportent des données concernant l’environnement des chasseurs-cueilleurs. La grande faune est dominée par le cerf dont les carcasses pourraient avoir été introduites incomplètes sur le site puis traitées pour en extraire la viande et la moelle. Nous avons bénéficié d’une analyse fonctionnelle croisée à l’étude typo-technologique des vestiges lithiques composés pour l’essentiel de silex locaux et régionaux. Ce double regard a permis de mettre en évidence une diversité d’activités mise en œuvre dans la cavité. Une pièce d’ocre rouge, quelques vestiges d’industrie osseuse et des éléments de parure participent également à la description d’une large gamme de tâches effectuées lors d’un séjour prolongé ou de plusieurs occupations successives. La comparaison des pointes de chasse microlithiques avec d’autres gisements sur une vaste échelle géographique conduit à discuter l’attribution de cet ensemble supérieur à différentes phases du Laborien. L’hypothèse d’un Laborien récent (ou Épilaborien) conduit à réfléchir à une perduration de morphotypes ancestraux parallèlement à de nouveaux types d’armatures, observation déjà réalisée notamment à La Borie del Rey dans le Haut-Agenais mais qui demande encore des précisions et de nouvelles découvertes. Discovered in 1990, Peyrazet cave-rock shelter (Creysse, Lot) lies in the Haut-Quercy region at the limits of the Martel limestone plateau, several hundred meters from the current Dordogne River valley. Excavations begun in 2008 produced a Late Glacial archaeo-sequence that sheds new light on several still poorly understood aspects of the archeological record in both the Haut-Quercy region and southwestern France in general. The level overlying the Late Magdalenian occupation produced limited evidence for the Azilian and is stratigraphically separated from the Laborian. This latter techno-complex, dated to the end of the Pleistocene and early Holocene, remains poorly documented in the region, having only been previously identified from two sites in the Quercy. The discovery of a recent Laborian (Epilaborian) occupation at Peyrazet presented the ideal occasion for a collaborative study of the diverse archaeological material recovered from this well-understood archaeo-stratigraphic context. A geoarchaeological analysis produced evidence for both surface runoff and the accumulation of coarse deposits (éboulis) as the principal site formation processes. In the southwest area of the site, a reworked lithofacies demonstrates substantial bioturbation in connection with animal burrowing. Although the presence of rodent, bird, fish, and medium-sized mammals (except hare) cannot be definitively connected to human activity, they nevertheless provide important information concerning the environments exploited by hunter-gatherer groups. Larger species are dominated by red deer whose carcasses were partially processed before being introduced to the site, where meat was subsequently removed and marrow consumed. A functional analysis combined with a typo-technological study of the primarily locally- and regionally-procured lithic material revealed evidence for diverse activities having taken place on-site. An ochre fragment, several bone tools and ornaments equally indicate a large variety of tasks to have been carried out during a single, long occupation or several successive visits. A typo-technological comparison of hunting weaponry (microliths) from sites across a substantial area suggests the assemblage to represent either a Laborian/Epilaborian mix or a unique Epilaborian occupation. This latter case would indicate the persistence of older morphotypes alongside the development of new tools forms, a situation already identified at Borie del Rey in the Haut-Agenais but which requires more detailed study supported by new discoveries.

International audience; Dune pattern, grain-size gradients and geochemistry were used to investigate the sources and dynamics of aeolian deposition during the last glacial in southwest France. The coversands form widespread fields of low-amplitude ridges (zibars), whereas Younger Dryas parabolic dunes mainly concentrate in corridors and along rivers. Spatial modelling of grain-size gradients combined with geochemical analysis points to a genetic relationship between coversands and loess, the latter resulting primarily from dust produced by aeolian abrasion of the coversands. The alluvium of the Garonne river provided also significant amounts of dust at a more local scale. The geochemical composition of loess shows much lower scattering than that of coversands, due to stronger homogenisation during transport in the atmosphere. Overall, sandy loess and loess deposits decrease in thickness away from the coversands. Dune orientation and grain-size gradients suggest that the efficient winds blew respectively from the W to the NW during the glacial, and the W-SW during the Younger Dryas. A comparison between the wind directions derived from the proxy data and those provided by palaeoclimatic simulations suggests a change of the main transport season. Ground surface conditions and their evolution throughout the year, i.e. the length of the season with snow and frozen or moist topsoil, and the seasonal distribution of wind speeds able to cause deflation are thought to have been the main factors that controlled the transport season in the study area.

The lower terraces of the Dordogne River at Bergerac (south-west France) were studied in detail using cores, trenches, ground penetrating radar profiles, and 14 C, optically stimulated luminescence and infrared stimulated luminescence dating. This study shows that the lowest terrace (Fx) is made up of two major lithostratigraphic units: (i) dominantly horizontal gravel strata interpreted as compound bar deposits in a braided river, which pre-date 18-17 ka, and (ii) thick lateral accretion gravel units (point bars) formed in an anabranching river during the Late Pleniglacial and Lateglacial. Most of the anabranching channels were abandoned at ca. 11-10 ka following shrinkage of the river bed into a single meandering channel and were partially filled by gyttjas during the Boreal chronozone. Finally, the channels were plugged by overbank fines until about 5 ka. Floods seldom reached the Fx terrace during the late Holocene and accretion became negligible. The main phase of bedrock incision spanned the Holocene, whereas the period of channel adjustment to change in river regime during late Marine Isotope Stage (MIS) 2 only led to a redistribution of the Pleniglacial gravels. The higher terrace (Fw3) formed before the Eemian and was covered by colluvial fans, mainly during MIS 2 and 3.

Numerous periglacial features (polygons, nets, soil stripes, ice-wedge pseudomorphs and sand-wedge casts, involutions) have been recorded in France by examining bibliographical sources and aerial photographs. These data show that a large part of France was affected by permafrost during the Pleistocene and only the southern Aquitaine Basin and Languedoc seem to have been beyond its maximum extent. The first OSL ages obtained from the aeolian infill of wedge structures indicate that at least two phases of thermal contraction cracking occurred in southwestern France between ∼25 and 36 ka. Chronostratigraphical data from loess in northern France indicate that these episodes correspond to the formation of ice-wedge networks associated with tundra gleys. In the latter region, two additional permafrost episodes probably occurred during the Last Glacial, the older one corresponding to the end of Marine Isotope Stage (MIS) 4 around 60 ka and the more recent one to MIS 2 around 19-16 ka. Although stratigraphical data indicate that these episodes were relatively short (about one millennium), relict permafrost may have existed for longer periods in northern France.

International audience; A database of Pleistocene periglacial features in France has been compiled from a review of academic literature and reports of rescue archaeology, the analysis of aerial photographs and new field surveys. Polygons, soil stripes, ice-wedge pseudomorphs, sand wedges and composite wedge pseudomorphs are included in the database together with their geographic coordinates, geological context, description and associated references. It is hoped that this database, which aim is to be integrated in broader studies, will stimulate further work on past permafrost reconstruction and will favour greater understanding of the climatic events that lead to the formation of the periglacial features. The database is available online on the AFEQ-CNF INQUA website (https://afeqeng.hypotheses.org/487). A folder that contains photographs and sketches of the features is also available on request.

Découverte en 1990, la grotte-abri de Peyrazet (Creysse, Lot, France) se situe dans le Haut-Quercy en bordure du causse de Martel, à quelques centaines de mètres du cours actuel de la Dordogne. Les fouilles menées depuis 2008 livrent une archéoséquence du Tardiglaciaire qui permet de combler certaines lacunes documentaires régionales et plus largement du Sud-Ouest de la France. Au Magdalénien supérieur succède un niveau ayant donné des indices d’un Azilien sensu lato stratigraphiquement séparé du Laborien, ensemble supérieur qui fait l’objet de cet article. Jusqu’alors ce technocomplexe de la fin du Pléistocène et des débuts de l’Holocène demeurait mal connu dans la région. En effet, seuls des travaux anciens menés dans deux gisements permettaient de noter sa présence en Quercy. La découverte d’un ensemble laborien récent (ou Épilaborien) à Peyrazet est l’occasion de conduire une étude collective des divers vestiges dans un cadre archéostratigraphique mieux maîtrisé. L’analyse géoarchéologique met en évidence l’action conjointe du ruissellement et de l’éboulisation comme principaux responsables de la mise en place des dépôts. Dans la partie S-O du site, un lithofaciès de remaniement indique une bioturbation importante en lien avec le creusement de terriers. Bien que leur origine ne soit pas liée aux activités humaines, les rongeurs, les oiseaux, les poissons et les mésomammifères (excepté le lièvre) apportent des données concernant l’environnement des chasseurs-cueilleurs. La grande faune est dominée par le cerf dont les carcasses pourraient avoir été introduites incomplètes sur le site puis traitées pour en extraire la viande et la moelle. Nous avons bénéficié d’une analyse fonctionnelle croisée à l’étude typo-technologique des vestiges lithiques composés pour l’essentiel de silex locaux et régionaux. Ce double regard a permis de mettre en évidence une diversité d’activités mise en œuvre dans la cavité. Une pièce d’ocre rouge, quelques vestiges d’industrie osseuse et des éléments de parure participent également à la description d’une large gamme de tâches effectuées lors d’un séjour prolongé ou de plusieurs occupations successives. La comparaison des pointes de chasse microlithiques avec d’autres gisements sur une vaste échelle géographique conduit à discuter l’attribution de cet ensemble supérieur à différentes phases du Laborien. L’hypothèse d’un Laborien récent (ou Épilaborien) conduit à réfléchir à une perduration de morphotypes ancestraux parallèlement à de nouveaux types d’armatures, observation déjà réalisée notamment à La Borie del Rey dans le Haut-Agenais mais qui demande encore des précisions et de nouvelles découvertes. Discovered in 1990, Peyrazet cave-rock shelter (Creysse, Lot) lies in the Haut-Quercy region at the limits of the Martel limestone plateau, several hundred meters from the current Dordogne River valley. Excavations begun in 2008 produced a Late Glacial archaeo-sequence that sheds new light on several still poorly understood aspects of the archeological record in both the Haut-Quercy region and southwestern France in general. The level overlying the Late Magdalenian occupation produced limited evidence for the Azilian and is stratigraphically separated from the Laborian. This latter techno-complex, dated to the end of the Pleistocene and early Holocene, remains poorly documented in the region, having only been previously identified from two sites in the Quercy. The discovery of a recent Laborian (Epilaborian) occupation at Peyrazet presented the ideal occasion for a collaborative study of the diverse archaeological material recovered from this well-understood archaeo-stratigraphic context. A geoarchaeological analysis produced evidence for both surface runoff and the accumulation of coarse deposits (éboulis) as the principal site formation processes. In the southwest area of the site, a reworked lithofacies demonstrates substantial bioturbation in connection with animal burrowing. Although the presence of rodent, bird, fish, and medium-sized mammals (except hare) cannot be definitively connected to human activity, they nevertheless provide important information concerning the environments exploited by hunter-gatherer groups. Larger species are dominated by red deer whose carcasses were partially processed before being introduced to the site, where meat was subsequently removed and marrow consumed. A functional analysis combined with a typo-technological study of the primarily locally- and regionally-procured lithic material revealed evidence for diverse activities having taken place on-site. An ochre fragment, several bone tools and ornaments equally indicate a large variety of tasks to have been carried out during a single, long occupation or several successive visits. A typo-technological comparison of hunting weaponry (microliths) from sites across a substantial area suggests the assemblage to represent either a Laborian/Epilaborian mix or a unique Epilaborian occupation. This latter case would indicate the persistence of older morphotypes alongside the development of new tools forms, a situation already identified at Borie del Rey in the Haut-Agenais but which requires more detailed study supported by new discoveries.

International audience

The Shi'bat Dihya 1 site in western Yemen, dated by optically stimulated lu-minescence to 55 ka, provides insight into the Middle Paleolithic peopling of the Arabian Peninsula. The archaeological layer is interstratified within thick, sandy silt floodplain deposits filling a piedmont basin. Luminescence dates, lack of soil development, and gypsum precipitation indicate a high accretion rate of the floodplain during Marine Isotope Stage 3, in connection with a (semi)-arid environment. Rapid overbank sedimentation was likely a result of the remo-bilization of loess material deposited on the Yemeni Great Escarpment at the periphery of the adjacent Tihama coastal sand desert or of other sources. Fabric and size analyses of the lithic artifacts, together with spatial projections, indicate site modifications by floods. Primary modifications include (1) selective accumulation of medium-sized lithic pieces as a result of hydraulic sorting, (2) bimodal orientation of artifacts, and (3) ripple-like arrangement of lithics and bone/tooth fragments. The overrepresentation of teeth may also be a consequence of sorting. Although floods have distorted the original site patterning, long-distance transport of artifacts by water can be excluded, as indicated by relatively high refitting rate, close proximity of artifacts derived from the same block of raw material, and lack of abrasion of the pieces. Therefore, the site is considered " geologically " in situ because its remobilization by water occurred shortly after human abandonment. This study also stresses that the effective preservation of a site cannot be assessed without careful taphonomic study, even in a potentially favorable depositional context such as silty alluvium. C 2012 Wiley Periodicals, Inc.

Archaeological investigations undertaken along a proposed highway together with the compilation of available geological and pedological data made it possible to give a first overview of the distribution of Pleistocene aeolian deposits in south- west France. A chronological framework for deposition has been obtained using both radiocarbon (n ¼ 24) and luminescence (n ¼ 26) dating. It shows that aeolian transport was very active during the Late Pleniglacial, between 15 and � 23 ka, leading to sand emplacement over a 13 000-m 2 area at the centre of the basin. The Pleniglacial coversands are typified by extensive fields of small transverse to barchanoid ridges giving way to sandsheets to the east. Subsequent aeolian phases, at ca. 12 ka (Younger Dryas) and 0.8-0.2 ka (Little Ice Age), correspond to the formation of more localized and higher, mainly parabolic dunes. At the southern and eastern margins of the coversand area, aeolian dust accumulated to form loess deposits, the thickness of which reaches � 3 m on the plateaus. Luminescence dates together with interglacial-ranking palaeoluvisols between the loess units clearly indicate that these accumulations built up during the last two glacial-interglacial cycles. The chronology of sand and loess deposition thus appears to be consistent with that already documented for northern Europe. This suggests that it was driven by global climate changes in the northern hemisphere. The relatively thin aeolian deposits (and particularly loess) in south-west France is thought to reflect both a supply-limited system and a moister climate than in more northern and continental regions. Copyright # 2011 John Wiley & Sons, Ltd.

The mid-west part of the Aquitaine basin is characterized by a vast sandy terrain, today covered by the Landes de Gascogne forest. This geological formation was recently the subject of new geomorphological and chronostratigraphic analyses, demonstrating that the formation corresponds to an erg that began to form in the early Quaternary. During the Late Glacial, the Sable des Landes was already a large natural unit in southwestern France. How did Magdalenian human groups appropriate this unique area ? And what was the impact of this desert on the mobility and exchange networks of these groups ? To date, surveys of the area have only documented two sites within this sandy desert clearly identified as belonging to the Upper Magdalenian : Tizon to the south and La Honteyre to the north. Compared with the more densely populated regions of Entre-Deux-Mers to the north and the western Pyrenees to the south, this area therefore appears to have been more constraining for hunter-gatherer groups, doubtless due to the low plant and animal biomass. The open-air site of La Honteyre, discovered in 1990 by G. Belbeoc''h and excavated between 1997 and 2000 by M. Lenoir, presents a single level with a relatively low thickness. We here propose a re-evaluation of the site in order to gain a better understanding of the technical and economic strategies implemented by Magdalenian hunter-gatherers in a sandy desert environment that was a priori constraining. In relation to previous studies, we present a qualitative evaluation of the taphonomy of the assemblage and propose a petrographic, technological, and typological analysis of the lithic remains. The results of the vertical projection of the coordinated remains, the spatial distribution of the lithic refits, and the typo-technological nature of the assemblage all indicate that the layer of remains is homogeneous. The assemblage is quite rich with a total of 25 663 lithic remains, including a significant proportion under a centimetre in size (> 15,000 items). The analysis of the siliceous raw materials indicates a supply area clearly focused northwards, in particular with the importation of roughly worked blocks transported from over 100 km away in the Charente region. Mid-distance from this (around 60 km), flint was also imported from deposits in the Dordogne. It appears that more distant materials may also have been imported (Cher Valley ?, ca. 350 km) as documented in the form of one or two objects. The high level of economic foresight illustrated by this behaviour perfectly illustrates a strategy of planning for the needs of a group that had come to occupy an area devoid of flint for blade knapping. It also highlights the importance Magdalenian groups placed on blade production. Finally, the presence of some bladelet cores made from local flint from Villagrains (15 km) shows some knowledge of the local environment. The low quantities of this flint could indicate a relatively short occupation of the site. Careful blade production has allowed blanks to be obtained for tools mainly involving pieces with lateral retouches, burins (including parrot-beak burins), bec-perçoirs and pointed blades. Blade knapping was based on raw material imported from the Charente area and the terraces of the Dordogne using the traditional methods of the period (unipolar, semi-tournant, soft organic percussion). A blade-bladelet knapping continuum used the same volume for intermediate blanks : small blades/ large bladelets. This economic objective can be observed in the presence of some original foliate lithic points (Laugerie-Basse type) and bladelets. An autonomous bladelet production complements these blanks, filling the need for blanks for hunting armatures on bladelets. Two main methods are involved in a single convergent unipolar concept for obtaining naturally pointed blanks. The backed bladelets present a typological diversity demonstrated in the manufacture of the pieces : backed, truncated, denticulated, inversely pointed, notched, and scalene triangles. Some specific objects such as certain burins and lithic points are good tracers for identifying the cultural links maintained between the occupants of La Honteyre and the sites located on either side of the Sable des Landes. Furthermore, the presence of parrot-beak burins and Laugerie-Basse points indicates clear interactions between the Vienne region and the western Pyrenees, an area that now includes the Sable des Landes thanks to the site of La Honteyre. Finally, the convergent unipolar bladelet production confirms the links between these sites and the cultural identity of these late Upper Magdalenian groups. It therefore appears that we are dealing with a site located in the heart of a cultural territory, confirmed by the widespread presence of specific objects and technical behaviour. Thus, by comparing the data from this site with other occupations to the south and north of the Sable des Landes, we can gain a better understanding of this constraining region as a place of passage for groups travelling from the north to the south, as implied by the broader circulation network of raw material between these different western Aquitaine sites., La partie centre-ouest du Bassin aquitain est caractérisée par une vaste couverture sableuse, aujourd’hui recouverte par la forêt des Landes de Gascogne. Cet espace correspond à un véritable erg sableux, dont la formation remonte au début du Quaternaire. Au cours du Tardiglaciaire, le Sable des Landes constitue déjà une grande unité naturelle au sein du Sud-Ouest de la France. Quel a été l’impact de ce désert sur la mobilité et les réseaux d’échanges des groupes humains vivant en Aquitaine au Magdalénien ? En l’état des données et malgré des prospections, seuls deux gisements bien caractérisés du Magdalénien supérieur sont connus dans ce contexte sableux : Tizon au sud et la Honteyre au nord. En l’état des découvertes, le Sable des Landes apparaît donc visiblement contraignant pour les groupes de chasseurs-collecteurs en relation sans doute avec une faible biomasse végétale et animale. La réévaluation du site de la Honteyre a pour objectif de mieux comprendre les stratégies techniques et économiques mises en oeuvre par les chasseurs-collecteurs magdaléniens dans ce contexte de désert sableux, a priori contraignant. Ce site de plein air a livré un niveau unique relativement peu dilaté mais clairement homogène. L’étude des matières premières indique une aire d’approvisionnement résolument tournée vers le nord avec en particulier l’introduction de blocs à peine dégrossis transportés depuis la Charente (> 100 km ; i. e. «grain de mil » ). Ce comportement économique prévisionnel illustre parfaitement la stratégie de planification des besoins d’un groupe venu occuper un espace dépourvu en volumes de silex suffisants pour des débitages laminaires. De plus, la présence de nucléus à lamelles en silex local (i. e. Villagrains) témoigne d’une connaissance relative de ce milieu mais soulignerait plutôt une implantation relativement courte dans ce territoire. La production lamino-lamellaire soignée a permis de fournir des supports d’outils et des armatures de chasse. Certains morphotypes permettent de préciser les liens culturels entretenus par les occupants de la Honteyre avec des gisements situés de part et d’autre du Sable des Landes. En outre, la présence de burins «bec-de-perroquet » et de pointes de Laugerie-Basse permet de tracer des relations évidentes entre la Vienne et les Pyrénées occidentales, espace intégrant désormais le Sable des Landes via ce jalon que constitue la Honteyre. De plus, une production lamellaire particulière livrant des supports naturellement pointus confirme ces liens inter-sites et appuie l’identité culturelle de ces groupes du Magdalénien supérieur récent. Ce gisement, perdu au milieu d’un erg sableux, est donc parfaitement intégré à un réseau culturel matérialisé notamment par la diffusion d’objets et de comportements techniques spécifiques. On peut alors mieux appréhender cet espace contraignant comme un lieu de passage de groupes transitant du nord au sud, comme semble l’indiquer le réseau plus large de circulation des matières premières entre ces différents gisements ouest-aquitains, lors de l’amélioration climatique du GI 1e., Gourc Laura, Langlais Mathieu, Sitzia Luca, Caux Solène, Belbeoc’h Gwénolé, Lenoir Michel. La Honteyre (Le Tuzan, Gironde) : une occupation de chasseurs-collecteurs magdaléniens en contexte de désert sableux. In: Bulletin de la Société préhistorique française, tome 113, n°4, 2016. pp. 713-735.

International audience; Detailed stratigraphic analysis and numerical dating (OSL, IRSL, ESR, 14C) of Pleistocene coversands in southwest France enable the construction of a renewed chronostratigraphic framework for sand depo-sition. The chronological data obtained from sandsheet units testify to the development of transgressive dunefields since at least the Middle Pleistocene (MIS 10). Three main phases of accumulation occurred during the Last Glacial. The oldest one (64e42 ka) is associated with wet sandsheet facies, histic horizons and zibar-type dune fields, which reflect deposition in a context strongly influenced by the groundwater table. The Late Pleniglacial (24e14 ka) corresponds to the main phase of coversand extension in a drier context. Silty gley horizons suggest, however, local interruptions of sand drifting during GS 2.1. Late-glacial stabilization of the coversands may not have occurred before GI-1c (Allerød), which was typified by the development of cumulic arenosols. These were covered by parabolic dunes during the Younger Dryas. The variations in extent of the emerged continental shelf during the glacialeinterglacial cycles may explain the uneven geographical distribution of sand deposition through time. Because of coastline retreat up to 100 km north of 45 N during the LGM lowstand, the coversands were unable to reach the northern part of the basin. Comparison with other European regions highlights stronger affinities of the French record with Portugal than with the Netherlands and Great Britain, probably because of reduced influence of permafrost.

We present a HJM approach to the projection of multiple yield curves developed to capture the volatility content of historical term structures for risk management purposes. Since we observe the empirical data at daily frequency and only for a finite number of time-to-maturity buckets, we propose a modelling framework which is inherently discrete. In particular, we show how to approximate the HJM continuous time description of the multi-curve dynamics by a Vector Autoregressive process of order one. The resulting dynamics lends itself to a feasible estimation of the model volatility-correlation structure and market risk-premia. Then, resorting to the Principal Component Analysis we further simplify the dynamics reducing the number of covariance components. Applying the constant volatility version of our model on a sample of curves from the Euro area, we demonstrate its forecasting ability through an out-of-sample test., 63 pages, 18 figures, 15 tables; new calibration procedure to estimate market risk-premia; new forecasting methodology; added references; minor revisions to the text

Using a Navier–Stokes isotropic turbulent field numerically simulated in a box with a discretization of 10243 (Biferale et al., 2005), we show that the probability of having a stretching–tilting larger than a few times the local enstrophy is low. By using an anisotropic kind of filter in the Fourier space, where wavenumbers that have at least one component below a threshold or inside a range are removed, we analyze these survival statistics when the large, the small inertial or the small inertial and dissipation scales are filtered out. By considering a flow obtained by randomizing the phases of the Fourier modes, and applying our filtering techniques, we identified clearly the properties attributable to turbulence. It can be observed that, in the unfiltered isotropic Navier–Stokes field, the probability of the ratio ( | ω ⋅ ∇ U | / | ω | 2 ) being higher than a given threshold is higher than in the fields where the large scales were filtered out. At the same time, it is lower than in the fields where the small inertial and dissipation range of scales is filtered out. This is basically due to the suppression of compact structures in the ranges that have been filtered in different ways. The partial removal of the background of filaments and sheets does not have a first order effect on these statistics. These results are discussed in the light of a hypothesized relation between vortical filaments, sheets and blobs in physical space and in Fourier space. The study in fact can be viewed as a kind of test for this idea and tries to highlight its limits. We conclude that a qualitative relation in physical space and in Fourier space can be supposed to exist for blobs only. That is for the near isotropic structures which are sufficiently described by a single spatial scale and do not suffer from the disambiguation problem as filaments and sheets do. Information is also given on the filtering effect on statistics concerning the inclination of the strain rate tensor eigenvectors with respect to vorticity. In all filtered ranges, eigenvector 2 reduces its alignment, while eigenvector 3 reduces its misalignment. All filters increase the gap between the most extensional eigenvalue 〈 λ 1 〉 and the intermediate one 〈 λ 2 〉 and the gap between this last 〈 λ 2 〉 and the contractile eigenvalue 〈 λ 3 〉 . When the large scales are missing, the modulus of the eigenvalue 1 becomes nearly equal to that of the eigenvalue 3, similarly to the modulus of the associated components of the enstrophy production.

During the last glacial period, a large part of the Aquitaine basin (southwest France) was a periglacial desert comprising coversands with low-relief dune fields surrounded by loess accumulations. OSL and radiocarbon dates show that the phase of maximum sand deposition coincides with Marine Isotope Stage (MIS) 2. Peats and gleyic palaeosoils intercalated within the sands at some sites indicate that vegetation cover was able to develop locally during short events, possibly D–O interstadials, due to raised groundwater levels in interdunal depressions. Few Palaeolithic sites have been discovered in the coversand area in contrast to the peripheral loess region. Systematic survey along a future highway corridor demonstrates that this paucity of sites is not the result of insufficient survey nor deep site burial, but rather reflects an archaeological reality. This strongly suggests that the sand area was not attractive for hunter–gatherer populations due to its reduced levels of water resources, and available vegetation and animal biomass. The distribution of cultural markers such as art items and projectile points also shows that the coversand area probably acted as a barrier separating two different cultural sub-areas, one in the Pyrenees and Cantabria, the other in the Perigord. As a consequence, the commonly accepted view that southwest France, as a whole, served as a refugia during the cold and arid phases of the Pleistocene should be replaced by a more complex one that reflects the fact that a large part of the territory was almost unoccupied and that human populations were concentrated along alluvial valleys.

National audience

International audience; The Arabian Peninsula has long been considered as a region devoid of long-term human settlement until the Holocene period, as a result of drastic climatic changes throughout the Pleistocene. It might be expected that the area was deserted during hyper-arid and arid periods, and populated by new migrant groups during humid events, according to a " push and pull " phenomenon. Although this scenario may be perfectly valid for a large part of the Peninsula, a set of recent data points to the persistence of populations in several regions, which may have served as refugia for human groups who developed their own technological traditions. Such a scenario is suggested by: (1) The succession of dense human occupations under arid conditions between ca. 60 and 50 ka, in the Wadi Surdud basin, a small sedimentary basin in the foothills of the Yemeni Western Highlands. This archaeological site complex encompasses several successive human settlements characterized by a Middle Paleolithic tradition which significantly differs from the Middle Paleolithic and Middle Stone Age contemporaneous traditions from neighboring regions; (2) The regional diversity of the Middle Paleolithic throughout the Saharo-Arabian arid belt during MIS 3, expressed by an array of local techno-typological facies that likely relate to distant and disconnected source regions where populations contracted when climate worsened. Together with a set of high-resolution archaeological contexts recently discovered in the Arabian Peninsula and dated to MIS 5, these data suggest that the major human expansion waves which occurred in the region during the Upper Pleistocene are correlated with the wet phases of MIS 5, while populations probably contracted into a few refugia areas at the beginning of MIS 3.

he Land Use and Cover Area frame Statistical survey (LUCAS) database on topsoil properties in Europe was used to map aeolian deposits. The points which satisfy the grain-size criteria of coversands, loess and transitional facies were extracted from the rasters of predicted soil texture established by kriging of the LUCAS data by Ballabio et al. (2016). A comparison with already available maps, derived from a conventional field approach, shows a good fit in most of the tested areas. The new map, however, suggests a greater extension of loess, which seems related to the inclusion of thin loess covers, usually omitted by conventional mapping, and the presence of previously unmapped areas due to lack of survey or misinterpretation. The main source of aeolian particles corresponds to glacio-fluvial sediments at the margin of the Scandinavian and Alpine ice sheets. Coversands and loess form a broad band across northern Europe, and in the Rh^one, Rhine and Danube valleys. Large areas on the outskirts of these deposits also received a significant loess contribution, which has been reworked in slope deposits. Conversely, southern Europe is characterized by much less loess accumulation. The Atlantic coast has transgressive dune fields that penetrate inland to varying degree

The recovery at Shi’bat Dihya 1 (SD1) of a dense Middle Paleolithic human occupation dated to 55 ka BP sheds new light on the role of the Arabian Peninsula at the time of the alleged expansion of modern humans out of Africa. SD1 is part of a complex of Middle Paleolithic sites cut by the Wadi Surdud and interstratified within an alluvial sedimentary basin in the foothills that connect the Yemeni highlands with the Tihama coastal plain. A number of environmental proxies indicate arid conditions throughout a sequence that extends between 63 and 42 ka BP. The lithic industry is geared toward the production of a variety of end products: blades, pointed blades, pointed flakes and Levallois-like flakes with long unmodified cutting edges, made from locally available rhyolite. The occasional exploitation of other local raw materials, that fulfill distinct complementary needs, highlights the multi-functional nature of the occupation. The slightly younger Shi’bat Dihya 2 (SD2) site is characterized by a less elaborate production of flakes, together with some elements (blades and pointed flakes) similar to those found at SD1, and may indicate a cultural continuity between the two sites. The technological behaviors of the SD1 toolmakers present similarities with those documented from a number of nearly contemporaneous assemblages from southern Arabia, the Levant, the Horn of Africa and North Africa. However, they do not directly conform to any of the techno-complexes typical of the late Middle Paleolithic or late Middle Stone Age from these regions. This period would have witnessed the development of local Middle Paleolithic traditions in the Arabian Peninsula, which suggests more complex settlement dynamics and possible population interactions than commonly inferred by the current models of modern human expansion out of Africa., The international Paleo-Y paleoanthropological research project, developed since 2005 by R.M. in agreement with the Yemeni General Organization for Antiquities and Museums (GOAM) and the Centre Français d'Archéologie et de Sciences Sociales de Sanaa (CEFAS), has been supported by the French Ministry of Foreign Affairs (to R.M.), the French CNRS Eclipse II project (to R.M.) and the L.S.B. Leakey Foundation (to A.D.). The Paleo-Y project was initiated thanks to the generous help of A. de Maigret (University of Naples) and J.-F. Jarrige (CNRS), and greatly benefited from the support of the University of Bordeaux 1 (UMR PACEA CNRS), the University of Poitiers (Department of Geosciences), the French Institut National de Recherches Archéologiques Préventives (INRAP), and also from the collaboration of the French Muséum National d'Histoire Naturelle and the University ‘La Sapienza’ of Rome. For research permission and collaboration, Paleo-Y is indebted to A. Ba-Wazir, General Director of the GOAM, A. Garallah, Deputy of the GOAM, and A.A. Mohsen, Governor of Al-Mahqwid. We acknowledge the extraordinary and continual support provided by J. Lambert and M. Tuchscherer, directors of CEFAS. The archaeological excavations at SD1 and SD2 were carried out under scientific direction of A.D. and J.J., respectively. In addition to the authors of this study, during the last years of the Paleo-Y fieldwork in Tihama, research at Wadi Surdud has benefited from contributions from E. Abbate, N. Abdulbaset, A. Abraudey, K. Al-Haj, M. Al-Halabi, A.S. Alrudy, A. Ballah, S. Boulogne, A. Coppa, E. Messager, H. Murad, M.A. Qasam, C. Thiébaut, P. Voinchet, and also received the friendly support of E.H. Awadh, A.M. Farea, I. Hehmeyer, and E. Keall, of the Granary's Museum of Zabid, and M.A. Al-Sayyani and M. Rajeh Murad of the GOAM. Additional research on the geo-mineralogical, geochemical, and paleoenvironmental aspects has been developed in France by M. Frouin, C. Hatté, A. Meunier, and A. Queffelec. M.-C. Noël and H. Goubar respectively assured most of the administrative and logistical aspects during fieldwork in Yemen. Thanks are also due to S. Antonini, S. Cleuziou, V. Eisenman, A. Froment, M.-L. Inizan, A.-M. Lézine. We are sincerely grateful to the people of the Al-Mahqwid and Tihama regions for their welcome and interest in our research and acknowledge the support of A. Auotnan, representative of the District of Khamis Bani Saad. The spatial analysis of S. Boulogne (INRAP) and F. Lacrampe-Lacuyaubère (Archéosphère), the final layout of the lithic drawings by G. Devilder (PACEA) and the editing of the text by B. Gravina (PACEA) have significantly enhanced the present paper. Our study has greatly benefited from the comments of R. Dennell, F. d’Errico, D. Begun, the JHE associate editor, and the suggestions of three anonymous reviewers.

La revue des données issues de l'archéologie préventive et programmée, des descriptions de coupes naturelles ou des photos aériennes conduit à recenser plusieurs centaines de structures périglaciaires dans le Sud-Ouest de la France. Plusieurs catégories sont distinguées : 1) réseaux de polygones supradécamétriques correspondant à des coins à remplissage sableux primaire ou mixte, 2) coin à remplissage sableux primaire et, 3) réseau de petits polygones correspondant à des fentes de gel à maille semi-métriques à métriques. La datation OSL du remplissage de plusieurs coins sableux et l'information stratigraphique issue de sites préhistoriques montre que ces différentes structures traduisent plusieurs d'extension méridionale du pergélisol pléistocène. L'interprétation de la signification paléoclimatiques des structures, sans être univoque, conduit à distinguer des épisodes de pergélisol continu/discontinu et/ou sporadique. L'hypothèse d'une récurrence de phases d'extension du Pergélisol européen pléistocène en réponse aux événements de Heinrich entre 32ka et 17ka est avancée.

By using a Navier-Stokes isotropic turbulent field numerically simulated in the box with a discretization of 10243 [Biferale et al. (2005)], we show that the probability of having a stretching-tilting larger than twice the local enstrophy is very small. This probability decreases if we try to filter out the large scales, while it increases filtering out the small scales. This is basically due to the suppression of the compact structures (blobs).

International audience; Découverte en 1990, la grotte-abri de Peyrazet (Creysse, Lot, France) se situe dans le Haut-Quercy en bordure du causse de Martel, à quelques centaines de mètres du cours actuel de la Dordogne. Les fouilles menées depuis 2008 livrent une archéoséquence du Tardiglaciaire qui permet de combler certaines lacunes documentaires régionales et plus largement du Sud-Ouest de la France. Au Magdalénien supérieur succède un niveau ayant donné des indices d'un Azilien sensu lato stratigraphiquement séparé du Laborien, ensemble supérieur qui fait l'objet de cet article. Jusqu'alors ce technocomplexe de la fin du Pléistocène et des débuts de l'Holocène demeurait mal connu dans la région. En effet, seuls des travaux anciens menés dans deux gisements permettaient de noter sa présence en Quercy. La découverte d'un ensemble laborien récent (ou Épilaborien) à Peyrazet est l'occasion de conduire une étude collective des divers vestiges dans un cadre archéostratigraphique mieux maîtrisé. L'analyse géoarchéologique met en évidence l'action conjointe du ruissellement et de l'éboulisation comme principaux responsables de la mise en place des dépôts. Dans la partie SO du site, un lithofaciès de remaniement indique une bioturbation importante en lien avec le creusement de terriers. Bien que leur origine ne soit pas liée aux activités humaines, les rongeurs, les oiseaux, les poissons et les mésomammifères (excepté le lièvre) apportent des données concernant l'environnement des chasseurs-cueilleurs. La grande faune est dominée par le cerf dont les carcasses pourraient avoir été introduites incomplètes sur le site puis traitées pour en extraire la viande et la moelle. Nous avons bénéficié d'une analyse fonctionnelle croisée à l'étude typo-(a