Land use and systematic survey in the study of hunter-gatherers from northwestern Patagonia, Argentina

In this paper, we focus on the results of the archaeological research in the Diamante Valley, the southernmost limit of the expansion of agriculture, sedentary societies, and the Inka empire (Fig. 1). We conducted the first fieldwork in this area involving random surface sampling, followed by test pits in open-air sites. Our analyses show changes in the settlement pattern of hunter-gatherer societies. During the first part of the Late Holocene (3000-1500 years BP), hunter-gatherers used the highlands and the piedmont seasonally. The archaeological evidence suggests a context of resource abundance and frequent movements from one patch of resources to the other in both biogeographic units. During the last part of the Late Holocene (post-1500 BP period), the increased demography made hunter-gatherers stay longer in each patch. In this later period, we observe a settlement pattern that combines, on the one hand, short-term particular tasks camps with shallow anthropogenic deposits, low artifactual density, richness, and diversity, and on the other hand, larger residential base camps with deep deposits, high artifactual density, richness, and diversity. We also find differences in how hunter-gatherers use the two biogeographic units. We find short-term non-residential camps and larger residential camps in the piedmont. Here we found versatile toolkits with abundant cores and cortex. Even though basalts are abundant in the highlands, there is a more significant amount of non-local raw materials, such as obsidians. Projectile points and scrapers dominate the assemblages, which might lead to task-specific activities such as hunting and processing guanacos. From these results, we can affirm that Late Holocene hunter-gatherer groups from Diamante Valley had an excellent knowledge of the landscape and took advantage of the different altitudinal gradients' different resources with an organized settlement pattern.