Obsidian hydration in northwestern Patagonia: Two case studies

FERNANDO FRANCHETTI; CHRISTOPHER STEVENSON; GUSTAVO NEME; ADOLFO GIL; LAURA SALGÁN

Engaru

Conferencia; Obsidian International Conference 2023; 2023

International Association for Obsidian Studies

The archaeology of Patagonia infers the past through a biogeographic approach focused on humanadaptations to arid environments across the Holocene. This framework main concerns are the exploration and occupation of new areas since the arrival of the first hunter-gatherers to the region.To better understand these processes, we explore ways to improve the chronology. In this paper wepresent the results of obsidian hydration dates in two case studies from northwestern Patagonia,Argentina. Our sample comes from Salamanca cave, located in the piedmont; and El Desecho located in the highlands. We put humidity and temperature sensors in the sites during one year at different depth to calibrate the dates. We processed the samples using Infrared Transmission Spectroscopy. We compared the obsidian hydration dates with radiocarbon dates identifying congruences and disparities. Obsidian hydration dates tend to show a more continuous and younger set of dates which concur with some radiocarbon dates from the Late Holocene. We discuss different challenges related to site formation processes and radiocarbon sampling that might affect the interpretation of the combined chronology in both sites.