Uranium-series isochron dating at El Castillo Cave (Cantabria, Spain): The "Acheulean"/"Mousterian" question

A massive flowstone layer, Level 23, near the base of the stratigraphic sequence in El Castillo Cave (Cantabria, Spain), is dated by the uranium-series isochron method to 89+11/−10 ka bp. The flowstone separates cultural layers traditionally labelled “Mousterian” (above) and “Acheulean” (below). The date reported here, in association with other recent age determinations for “Mousterian” and “Acheulean” artifact assemblages in Western Europe, calls into question the temporal significance of these archaeological designations. In addition, it further underlies the importance of the Castillo cultural sequence and allows tentative discussion of changing rates of sedimentation in the vestibule of the cave, where some 18 m of cultural and geological deposits were laid down during the course of the Upper Pleistocene.