JOIN USScientists have discovered a 3,000-year-old rectangular copper mask in Argentina - one of the oldest human-made metal object from South America.
The mask, that dates back to about 1000 BC, was found at a site where adults and children were buried.
Holes mark the position of the mask's eyes, nose and mouth, with additional small, circular openings near the edges that could have been threaded to secure it to a face or an object.
Scientists from University of Buenos Aires in Argentina also found a source of copper ore within 70 kilometres of the location where the mask was uncovered, suggesting that it was produced locally.
It is probable that metalworking emerged in Argentina at the same time that it was developing in Peru, the researchers wrote in the study published in the journal Antiquity.
The metal mask - along with a collection of human bones — was found in a tomb near a village in northwestern Argentina.
There were about 14 bodies in the burial area, with the bones all mixed together and the mask placed on top of one corner of the pile.
Another burial area nearby held a single occupant. The bones of a child about 8 to 12 years old, also dating to about 3,000 years ago, were buried with a stone bead and a copper pendant, 'Live Science' reported.
The mask measures about 18 centimetres long and nearly 15 cm wide. To create the mask, someone would have hammered the metal flat while it was cold and then reheated it, researchers said.
The age of these metal objects - particularly the mask, crafted to deliberately resemble a human face - strongly suggests that people in the Argentinian regions of the Andes were shaping copper into artifacts earlier than previously thought, they said.