Résumé
The stratigraphic observations conducted at Waziers "Le Bas-Terroir" between 2011 and 2015 are spread over approximately 12 ha and were carried out in various intervention contexts (Herisson et al., 2022) using different methods : mechanical pit surveys, geotechnical borings, mechanical auger surveys, and detailed cross-sections. After locating and presenting the main information acquired for each set of observations, we synthesize the stratigraphy mainly from the detailed surveys of the 2014-2015 excavations. We define seven main stratigraphic units, possibly divided into sub-units, from bottom to top: US1 ante-Quaternary substratum, US2 Quaternary slope deposits, US3 coarse alluvial silt, US4 light alluvial silt locally affected by load-casts, US5 silty or peaty alluvial deposits, US6 gullies and reworking of previous deposits, US7a coarse alluvial sheet and US7b-c fluvio-aeolian deposits. The biozones defined by malacology (Limondin-Lozouet, 2022) and palynology (Gauthier, 2022) allow correlations between the 2014-2015 excavations and the observations of the "puisard" (sump) pit and "SC" core samples (about 300 meters away) and a first chronological attribution: Saalien for member 1 (US4 and US5), Eemian for member 2 (US5). The merging of Members 1 and 2 defines the Waziers Formation. The extensive nature of the observations and the geophysical studies (Hulin & Virmoux, 2022), make it possible to apprehend the great extent of the ancient alluvial deposits whose upstream and downstream limits are not yet known. The lithostratigraphic framework presented here allows us to reposition the different studies associated with the deposit: palynology (Gauthier, 2022), macro-plant remains (Audiard et al., submitted), malacology (Limondin-Lozouet, 2022), mammals (Auguste et al., 2022), micro-mammals (Lebreton et al., sous presse), proteogenomics (Bray et al., submitted), ESR and U/Th dating (Bahain et al, 2022), isotopic geochemistry on large mammal teeth (Marechal et al., 2022) and archaeological data (Herisson et al., submitted), before synthesizing them (Deschodt et al., submitted)