Chemical analysis of rare earth elements reveals trade between the Indian Ocean and the Mediterranean 2,500 years ago

Gianni Gallello, Mirco Ramacciotti and Agustín Pastor, from the ArchaeChemis tea
Gianni Gallello, Mirco Ramacciotti and Agustín Pastor, from the ArchaeChemis team, with ICP-MS equipment to measure rare earth elements
A multidisciplinary research team from the University of Valencia (ArchaeChemis) and Italian and Indian research centres has confirmed that the archaeological site of Alagankulam (India) was one of the main ancient ports in south-eastern India and a transoceanic connection point between East and West during the Classical period, approximately 2,000 to 2,500 years ago.

The rare earth elements (REE) methodology developed by the ArchaeChemis Unit marks the trace of human activity in the sediments found at the sites. Together with the archaeological evidence, they would suggest a gradual development of the settlement, with a peak of frequentation, expansion and human activity at the beginning of the Classical period, in a chronological span from 400 to 100 BC, according to the radiocarbon dating obtained.

Data from the analysed sediments show evidence of anthropogenic activities at the Alagankulam site, located on the south-east coast of India, off the island of Sri Lanka. "In particular, they confirm that a variety of functions such as food production, pottery making, metal forming and other manufacturing activities were carried out in this site. Therefore, there was a very complex and multifunctional community", highlights Gianni Gallello, researcher at the Department of Prehistory, Archaeology and Ancient History of the University of Valencia (UV).

In the research, which also involves the Italian Institute for the Chemistry of Organometallic Compounds, the Polytechnic University of Milan and the Vellore Institute of Technology (India), the chemical results are consistent with the archaeological evidence. "At the top of the strata, the quantity of elements increases considerably, including precious and luxury ware and ornamental objects, as a result of the more intense commercial exchanges and the new connections established", explains Mirco Ramacciotti, also a researcher at UV.

"The study is an example of how rare earth elements can be used to highlight and map traces of invisible patterns which could interpret the complexity of the archaeological record", says Agustín Pastor, professor in the UV’s Department of Analytical Chemistry. This study has confirmed that the site was the main cultural and economic emporium in southern present-day India.

The research is part of a wide Italian-Indian project aimed at reconstructing the commercial, cultural and production centres of Tamil Nadu, an Indian state in the south-east of the country, bordering Sri Lanka.

Annex photo caption :

Alagankulam site, located on the south-east coast of India, off the island of Sri Lanka.

Selvaraj, Thirumalini et al. "Rare earth elements sediment analysis tracing anthropogenic activities in the stratigraphic sequence of Alagankulam (India)". Heliyon, Volume 10, Issue 9, e29767. DOI: https://doi.org/10.1016/j­.heliyon.2­024.e29767