Strontium provenancing wooden artefacts from Pitch Lake, Trinidad

Several wooden artefacts were found at Pitch Lake, Trinidad, one of the world's largest asphalt 'lakes', and a recent dating programme has shown that they range from ca. AD 600 to 3000 BC. This paper reports on the investigation of their provenance through strontium isotope analysis, with the aim of establishing whether the artefacts were made locally or were imports from other regions of Trinidad or even beyond the island. The challenge of working with wooden artefacts found in a pitch lake is contamination: while ensuring the overall preservation of the artefacts, the pitch and other elements present in the lake, could add some exogenous strontium to the samples leading to erroneous measurements. This paper provides an overview of the extensive pre-treatment protocols to remove any possible contamination from the samples, and compares the results achieved to those from over 130 modern plant samples spanning Trinidad and Tobago collected during recent fieldwork. We discuss the possible origins and the implications for the understanding of interactions in and beyond Trinidad.