Bioturbation and the upward movement of sediment particles and archaeological materials: comments on Bueno et al.

► Bueno et al. show data from a Paleoindian site that suggests upward vertical movement of small archaeological pieces (<2 mm). ► The reasons advanced for this could be eolian activity coupled with bioturbation as a complementary mechanism. ► The literature on tropical bioturbation points to leaf-cutting (harvester) ants as playing a major role. ► Eolian activity was probably not a significant factor in this case.