CONICET | Buscador de Institutos y Recursos Humanos

The study of the presence of obsidian in different archaeological sites in the northern coast of Patagonia (Argentina) has begun to be systematized in recent years. In particular, on the coast of San Matías Gulf (Río Negro province) it has been determined that this raw material is mostly represented along the west coast of the Gulf (Figure 1) and there has been a general pattern of declining abundance from South to North. That is, on the northern coast of the study area, the representation of this rock is significantly lower (Cardillo and Scartascini 2007). Different sources of origin of this rock have been detected through geochemical studies of recovered samples: Telsen and Sacanana in Chubut province (225 and 380 linear km distant, respectively), the Somuncurá plateau and Cantera Lolog (Neuquén province), the latter located 560 linear km from the study area (Favier Dubois et al. 2009). Through the implementation of new geochemical analysis a sample from a new source has been detected on the west coast of the Gulf. This sample comes from Portada Covunco in Neuquén province, 500 linear km away (Stern et al. 2012). This finding is of particular importance since it is the first time that this type of obsidian, that has a visually distinctive red and black banding and is also found on the Pacific Coast in Chile, is found on the Atlantic coast of Patagonia. In this paper obsidian we characterize the obsidian types present at San Matías gulf coast, we perform a techo-morphological analyses of the recovered artifacts, and we make comparisons with archaeological sites of the northern coast of Chubut (central Patagonia) to detect, in different parts of the coast, samples that come from the same sources. By this means we hope to better evaluate trends in the circulation and use of this raw material at San Matías Gulf during the Middle and Late Holocene.