Les dépôts du site magdalénien de Gandil à Bruniquel (Tarn-et-Garonne) : dynamique sédimentaire, signification paléoenvironnementale, lithostratigraphie et implications archéologiques

摘要

The deposits of the Gandil Rockshelter were laid down in fluvial context during the Oldest Dryas episod. They represent two successive depositional sedimentary environments : lateral gravel bar deposits (hthofacies Gm and Sh-SI) then levee and flood plain deposits (hthofacies Fl and Fm). On this dynamic evolution basis, the Gandil stratigraphie series can be subdivided into two distinct sedimentary units. They do not imply any change in morphologic and/or climatic environment but only a lateral shifting of the sedimentary zones. After or at the end of this depositional phase, probably during the Bölling-Alleröd episod, takes place a ten meters-depth downcutting of the Aveyron valley up to its present level. From the flow regimes related to the identified depositional environments, we can infer that archaeological assemblages found in Gm have probably suffered important reworkmgs whereas those enclosed in Fm have experienced only weak displacements. The former is not very favourable for an archaeostratigraphic and palethonological approach ; it is not the case for the latter. Moreover, paleoenvironmental data allow to state that magdalenian layers enclosed in deposits Gm correspond to short-lasting recurring settlements on a lateral gravel bar of the Paleo-Aveyron and those found in deposits Fm represent occasional settlements on the inner part of a vegetated flood plain.