• Soares, António M. Monge
• Cardoso, João Luis
• Silva, R. J. C.
• Pereira, Filipa
• Araújo, Maria Fátima

Abstract

The Chalcolithic site of Moita da Ladra, on the right bank of the River Tagus, near Vila Franca de Xira (Portugal), was mainly settled during the second half of the 3rd millennium BC. The large amount of metal artefacts and metallurgical remains recovered at the site indicates local metallurgical activities. Chemical and microstructural characterization of 62 copper-based artefacts and 8 metallic nodules from the settlement are presented. Micro-EDXRF, optical microscopy, SEM-EDS and Vickers microhardness testing were applied in this research. Elemental determinations show artefacts containing variable amounts of arsenic. Forty five percent of the artefacts have an arsenic content at impurity level (As < 2 wt.%), while the remaining items range from 2.0 wt.% to 5.4 wt.% As. Microstructural analysis shows that artefacts were shaped by hammering and annealing cycles, being 33% of the artefacts finished by cold working. Metallic nodules were produced by smelting operations, and are chemically consistent with the analysed artefact collection. Results are compared with those obtained by similar researches carried out on important contemporary materials from the same geographical area (Portuguese Estremadura) and other Iberian regions (Southern Portugal and Western Andalusia).

Topics

• scanning electron microscopy
• copper
• annealing
• Energy-dispersive X-ray spectroscopy
• optical microscopy
• Arsenic