Last Glacial palaeoenvironments at Lascaux, southwest France, with special emphasis on MIS 4 (Ognon II interstadial)

•MIS 4 peats filling a doline at Lascaux, southwest France•Pollen, seeds, and beetle remains portray the image of a cool steppe with willow stands.•Local vegetation of aquatic and hygrophilous plants•OSL ages and palaeoenvironnemental data compatible with Ognon II interstadial•Peats buried by 6 m-thick pleniglacial slope deposits

A deep sequence of Last Glacial peats and slope deposits at the foot of the Lascaux hill was investigated using a large array of methods (geology, geophysics, 14C and OSL dating, palynology, macro-remain analysis, entomology). The peaty levels, OSL dated to between ~ 73 and 60 ka, are found within a doline developed in a fluvial terrace of the Vézère River. These gyttja and chalky gyttja deposits covered by fen peat yielded abundant beetle and plant (seeds, pollen) remains. Palaeoecological reconstructions suggest a cool steppe with willow stands compatible with an interstadial of marine isotopic stage (MIS) 4, probably Ognon II (GI-19.2). Aquatic and hygrophilous plants (sedges), which reflect local vegetation, and their dependent insects are equally well represented in the record. The peats are covered by a sequence of slope deposits: a coarse-grained lower unit deposited during late MIS 4, overlain by a heavily decalcified sandy unit with a boreal soil complex correlated with early MIS 3, and finally, a coarse-grained, calcareous unit formed during late MIS 3 and MIS 2 in connection with slope dynamics typical of periglacial environments. The palaeosols yielded a small Middle Palaeolithic lithic assemblage.