Millennial climatic instability during penultimate glacial period recorded in a south-western France speleothem

•We provide a high resolution record of earlier MIS6 based on speleothem data.•The carbon isotopic composition signal yields 5 stadial–interstadial cycles.•Intra-interstadial variability is visible.

This study focuses on an earlier MIS (marine isotopic stage) 6 flowstone deposit (Vil-car-1 core, Villars Cave, SW-France) that recorded millennial scale climatic events. This speleothem provides a high resolution record of the penultimate glacial period on mid-latitude land. The flowstone high growth rate and the episodes with depleted calcite δ13Cc values suggest that marine isotopic substage 6e environmental conditions were relatively warm and humid. Its δ13Cc profile clearly displays five main climatic oscillations from 177 to 165 ka, correlated with stadial–interstadial events. Similarly to the MIS3 period, the transitions in between those interstadials and stadials are characterised by abrupt changes and intra-interstadial variability is observed.