Redefining SW Amazonian chronologies and pottery use at the Teotônio site

Teotônio is a pre-Columbian riverine archaeological site located in southwestern Amazonia, in a region with diverse cultural traditions and linguistic variety, and an archaeological record marking one of the oldest occupations in the Amazon. The site has a long history of nearly continuous human occupation spanning most of the Holocene, predicated by a stratigraphic sequence containing important pre-ceramic and ceramic traditions. As such, Teotônio offers a valuable opportunity to improve our understanding of the human landscape in southwestern Amazonia during the late Holocene. This work aims to provide a reliable chronology for Teotônio by producing new radiocarbon measurements and building a revised chronology using Bayesian chronological modelling. Through organic residue analysis (ORA), we run a pilot study to discern pottery vessel function according to ceramic tradition by characterising preserved lipid residues using supercritical fluid extraction and gas chromatography-mass spectrometry. Bayesian modelling estimates the start and end of the cultural sequence at Teotônio to 10540–9425 cal BP and 625–395 cal BP (or CE 1325–1555), respectively, with a total duration between 8840 and 9980 years. ORA results for the ceramics show the presence of palmitic and stearic acids and resinous diterpenoids in most samples. These preliminary findings align with ethnographic traditions observed in the region, whereby resins from local flora are used for ceramic surface treatment, fuel, and/or medicinal purposes—although more work is required for validation. Together, the updated chronology and pilot study results contribute to our understanding of cultural practices and their maintenance through time, as well as specific human-environment interactions in southwestern Amazonia.