THE MIDDLE AND UPPER PLEISTOCENE LOESS SEQUENCE OF ÉTRICOURT-MANANCOURT (PICARDY, FRANCE): A REFERENCE PEDO-SEDIMENTOLOGICAL RECORD FOR THE LAST 350 KA In this study, we describe a new Middle Pleistocene loess-palaeosol sequence uncovered during a preventive excavation at Étricourt-Manancourt$\~$(Somme,$\~$France;$\~$fig.$\~$1).$\~$The$\~$full$\~$12-m-thick$\~$sequence$\~$exhibits$\~$five$\~$stacked$\~$glacial-interglacial$\~$cycles$\~$and$\~$ integrates$\~$five$\~$in situ$\~$Palaeolithic$\~$levels$\~$and$\~$remarkably$\~$one$\~$Acheulean$\~$level$\~$dated$\~$by$\~$TL$\~$on$\~$burned$\~$flints$\~$at$\~$about$\~$280 - 300 ka. Detailed$\~$field$\~$stratigraphic$\~$approach$\~$has$\~$been$\~$completed$\~$by$\~$(1)$\~$a$\~$high-resolution$\~$sedimentological$\~$study$\~$(grain$\~$size,$\~$TOC)$\~$ based on a set of more than 380 5-cm-thick samples collected from continuous sampling columns covering the entire units, (2) more$\~$than$\~$110$\~$micromorphological$\~$block$\~$samples$\~$for$\~$thin$\~$sections$\~$analysis$\~$(fig.$\~$3)$\~$and$\~$(3)$\~$a$\~$set$\~$of$\~$37$\~$sub-samples$\~$for$\~$the$\~$study$\~$ of$\~$heavy$\~$minerals.$\~$Despite$\~$specific$\~$samples$\~$(tubes)$\~$having$\~$been$\~$extracted$\~$for$\~$future$\~$OSL$\~$dating,$\~$the$\~$geochronological$\~$control$\~$is$\~$ mainly$\~$based$\~$on$\~$TL$\~$dating$\~$of$\~$heated$\~$(archaeological)$\~$flints,$\~$completed$\~$by$\~$IRSL$\~$dating$\~$on$\~$K-feldspars. The archaeological excavation, located on the slope of a dry valley, was opened over more than 4500 m${^2}$ and led to the discovery$\~$of$\~$two$\~$deep$\~$sinkholes$\~$developed$\~$in$\~$the$\~$chalk$\~$bedrock$\~$(fig.$\~$6).$\~$The$\~$bottom$\~$of$\~$the$\~$deepest$\~$one$\~$is$\~$located$\~$at$\~$more$\~$than$\~$ 11 m from the surface of the topsoil and 5 m below$\~$the$\~$average$\~$chalk$\~$surface.$\~$The$\~$study$\~$of$\~$four$\~$reference$\~$profiles$\~$distributed$\~$ throughout$\~$the$\~$excavation$\~$(figs.$\~$6-9),$\~$and$\~$their$\~$correlation$\~$using$\~$well$\~$defined$\~$pedological$\~$level$\~$marks$\~$led$\~$to$\~$the$\~$definition$\~$of$\~$ a ca. 12-m-thick cumulative loess-palaeosols succession including eighteen main stratigraphic units. This approach allowed building a global pedosedimentary sequences for the Étricourt site that presently serves as a reference for northern France (fig.$\~$14$\~$&$\~$tab.$\~$2).