Necklace is 'oldest in Americas'

Radiocarbon dating puts its origin at about 4,000 years ago, when hunter-gatherers occupied the area.

The researchers say it appears to have been fashioned from gold nuggets.

The discovery suggests that the use of gold jewellery to signify status began before the appearance of more complex societies in the Andes, they report.

Writing in the journal Proceedings of the National Academy of Science (PNAS), they say the artefact is the earliest worked gold found not only in the Andes, but the Americas as well.

Study leader Dr Mark Aldenderfer of the department of anthropology at the University of Arizona, Tucson, said it demonstrated an emerging social role for gold beyond simple decoration.