Innovations in Acheulean Biface production at la Noira (France) during Middle Pleistocene in Western Europe

Abstract The archaeological sequence of la Noira (Centre region, France) yielded two phases of occupation: ca 700 ka (stratum a) and ca 450 ka (stratum c). No site between these two dates has yet been discovered in the area, and this chronological period has thus been interpreted as a gap in settlement from MIS 16 to MIS 12, two crucial phases of occupation in Western Europe, before and after the long glacial event MIS 12 which record the onset of the Acheulean in Europe and earliest evidence of innovations from MIS 12 considered as a shift in human evolution. Here, we compare these two levels and track technological innovations during this time, combining technological analysis with geometric morphometrics with the use of 3D models comparison of the Large Cutting Tools (LCTs). Stratum a yielded an Early Acheulean, one of the few evidence in Europe presents tools with mainly short shaping sequences on local millstone slabs, with special attention to tips, but with clear management of tool volume. Stratum c, dated to the MIS 11, differs in that both local millstone and flints from distant sources show longer shaping sequences, the use of soft hammers for several series of removals on tools, combined with final regularizing retouch on entire edges. The morphometric approach shows a morphological transition from oval to teardrop shapes for the thinnest tools. Our data suggest a clear technological filiation between strata a and c and in la Noira populations from MIS 16 and MIS 12, as suggested for innovations of core technologies and land-use patterns, and raise question on local human behavioral evolution over the Middle Pleistocene in Western Europe.