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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 Périgord. 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.  相似文献   
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This study explores the interrelationship between the genus Canis and hunter–gatherers through a case study of prehistoric Native Americans in the San Francisco Bay-Sacramento Delta area. A distinctive aspect of the region's prehistoric record is the interment of canids, variously classified as coyotes, dogs, and wolves. Since these species are difficult to distinguish based solely on morphology, ancient DNA analysis was employed to distinguish species. The DNA study results, the first on canids from archaeological sites in California, are entirely represented by domesticated dogs (including both interments and disarticulated samples from midden deposits). These results, buttressed by stable isotope analyses, provide new insight into the complex interrelationship between humans and canids in both ritual and prosaic contexts, and reveal a more prominent role for dogs than previously envisioned.  相似文献   
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A new species of fossil wood is described, Bridelioxylon canningense Bamford & McLoughlin, belonging to the Phyllanthoideae group of the Euphorbiaceae. The woods occur in indurated sandstones and conglomerates preserved in palaeochannels incised into the Upper Permian Condren Sandstone in the Landrigan Cliffs, northern Canning Basin, Western Australia. Based on the presence of the dicotyledonous woods and the geomorphological setting of the palaeochannel, a Palaeogene age is suggested for the host rocks. This is the first record of fossil euphorbiacean wood in Australia; pollen has been previously recorded. The fossil wood is most closely comparable to extant members of Bridelia that currently occupy the warmer and wetter parts of Australia.  相似文献   
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