Primary quarrying at La Gruta locality (Patagonia, Argentina).

FRANCO, NORA VIVIANA; VETRISANO, LUCAS

Tarragona

Congreso; Rock and Roll: 13th International Symposium on Knappable Materials; 2021

Institut Catalá de Paleoecología Humana ? Institució CERCA ? Excelencia María de Maetzu, Agencia Estatal de Investigación ? Universitat Romira ? Madrid Institute for Advance Study

La Gruta locality is situated at the Southern End of the Deseado Massif (SDM, Pata-gonia, Argentina). It is part of a morphostructural region with seasonal lagoons and streams highly dependent on rainfall where early dates of human occupation in South Patagonia have been identified. The area is rich in rockshelters and both primary and secondary sources of high quality siliceous rocks, which are more abundant to the North.Humans have utilized La Gruta locality since ca. 12,800 cal yr B.P. and there are dis-continuous evidences of occupation of this area until ca. 156 cal yr B.P. Throughout its occupational history, environmental and technological changes have been recorded. In order to understand human behavior and raw material utilization, a good knowledge of the local lithic structure is needed. This is especially difficult in this area because of the great variability in both primary and secondary sources. Detailed surveys had shown the prevalence of extensive secondary sources, highly variable in terms of size, quality and type of rock, which are mainly located in canyons and lagoons. On the other hand, only seven primary sources were identified. They are all siliceous outcrops of regular to very good quality, very limited in size. They are very heterogeneous in their silicification degree due to their hydrothermal origin, which makes them uneven in quality and rich in flaws, such as cracks. Quarry analysis, which includes artifact frequency, distribution, as well as their tech-nological characteristics, show that only two of these outcrops were exploited. Arti-facts recovered at both quarries, including tested cobbles, cortical flakes and cores, indicate in situ primary reduction. According to the archaeological record, these raw materials could have been used since ca. 12,800 cal BP. Additionally, at least one of them could also have been used during the early Holocene, as laminar blades from prepared cores have been identified.The comparison with the archaeological record indicates that the quarrying of primary sources was indeed very limited, which is consistent with low populations densities, the local abundance of very good secondary sources and the presence of better lithic raw materials to the North. The quarrying of raw materials in other areas and their transport to La Gruta locality could explain the diversity of the artifact assemblage recovered.