Lithic taphonomy of the Quebrada de Quereo site: addressing the problem of anthropogenic ambiguity in Late Pleistocene assemblages

Abstract

This paper aims to develop an analytical proposal for dealing with ambiguity in lithic material of late Pleistocene contexts in alluvial locations. We focus our study on the Quebrada de Quereo site (13480-13070 cal BP) located in the coast of Northern Semiarid Chile. To build a comparative analog, different combinations of taphonomic and technological variables are explored in an assemblage of natural origin from a nearby ravine that mimics lithic knapping attributes. This same set of variables was tested on the anthropogenic lithic assemblage of the Quebrada Santa Julia site (12990-12730 cal BP). This procedure allowed us developing an analytic system centered on the characteristics of chipped edges to weigh taphonomic and technological attributes and their natural production in torrential ravine contexts. By applying this scheme to a sample of the lithic material of Quebrada de Quereo, we discuss which pieces are most likely to be considered as lithic artifacts. We conclude that most of the Quebrada de Quereo lithic assemblage may be explained as produced by natural causes, thus those pieces should be considered pseudo-artifacts.