Heat treatment and changes in siliceous rock quality in the Southern End of the Deseado Massif (Patagonia, Argentina)

Abstract

The use of high-quality rocks and heat-treatment by hunter-gatherers during the initial exploration and colonization of America has been emphasized by different authors. Here we present the case of the Southern End of the Deseado Massif, where human occupations have been dated from the PleistoceneHolocene transition until historical times. Results of an intense survey of lithic resources show the presence of primary and secondary sources of middle and high quality siliceous rocks, most of them of hydrothermal origin. These siliceous rocks have a highly localized occurrence and, in most cases, their quality does not match the one found at the archaeological record –which encompasses logistic sites, multiple activity sites and caches of artifacts–. Here we present the results of heat treatment experiments on local available rocks, focusing in samples mainly from primary sources. Results obtained are compared with the artifacts found, in order to evaluate the potential utilization of the different sources and the presence of heat treatment in the local archaeological record.