The enigma of iron tools that predate the Iron Age has long puzzled archaeologists. Over decades evidence accrued that the iron was of meteoric, not terrestrial, origin. Now Albert Jambon of the French Museum of Natural History has reanalyzed a collection of artifacts going back as much as 5,000 years in age, and found that every single one was made of meteoritic metal.
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Based on an innovative geochemical approach, enabling distinction between terrestrial from extraterrestrial forms of iron, he found zero evidence of precocious smelting during the Bronze Age, Jambon reports in the Journal of Archaeological Science.
Of course, ancients might have been smelting iron earlier than we think. Perhaps we simply haven't found the evidence. But it is now abundantly clear that before the Iron Age, ancient artisans would help themselves to iron from meteorites, which they would hammer into shapes that could be quite elaborate.
The Iron Age is generally considered to have begun roughly 3300 years ago in what is today southern Turkey or the Caucasus. In other words, over two thousand years before that, people had discovered iron, albeit of extraterrestrial origin.
Ancient Egyptians were famously among those exploiting meteoric iron-nickel alloys, hammering the material into beads over 5,000 years ago in Gerzeh. Over a thousand years later, meteoric metal would be fashioned into elaborate artifacts for the 18th Dynasty pharaoh Tutankhamen, who ruled from 1332 to 1323 B.C.E., about a century before the Iron Age began. His iron treasures included parts of a dagger, a bracelet and a headrest. Metallurgic analysis showed back in the 1960s (and confirmed in 2016) that those were of meteoric origin, a finding reconfirmed now by Jambon.
In fact, the iron work found with Tutankhamen's remains had been of such high quality that latter-day archaeologists speculated the ancient Egyptians had achieved "significant mastery" of iron-working, centuries before the Iron Age began.
Jambon also re-analyzed the beads, which are the oldest metalwork found to date. Their somewhat deteriorated remains had been discovered at Gerzeh in southern Egypt. He also revisited a dagger from the Neolithic settlements at Alaca Höyük, central Turkey tentatively dated to about 4500 years ago, a pendant found in Syria dating to 2,300 B.C.E., items found in ancient Ugarit, including an axe, and several Chinese artifacts from the Shang dynasty, about 3,400 years old.
His analyses revealed that each of these Bronze Age artifacts had been made using meteoric iron.
When large celestial bodies like Earth are forming, nearly all nickel, being a heavy element, drifts towards the molten iron core. Nickel is extremely rare on the planet surface. But at least some meteorites were created by planets being destroyed and shattered.
Almost all the meteorites that have crashed on earth so far, which were identified and analyzed, consisted mainly of stony iron, alloyed with a small proportion of nickel – which is still greater than the concentration of nickel found in any known rocks on earth's surface.
Meteorites typically contain trace cobalt as well and may contain other rare elements, such as gold.
The point is, the proportionate concentrations of metal in meteors do not exist on Earth. They are atypical. So if we found that a powerful pharaoh had a knife or gadget made of this atypical metal, we can conclude that his people hammered it for him from meteoric iron.
Jambon points out that conveniently for ancient metallurgists, meteoric iron is already in a metal state, ready for use, while extracting iron from terrestrial requires smelting – the process of reduction, removing oxygen atoms bound to the metal.
Once smelting was discovered, says Jambon, since iron ore is very common, people stopped making artifacts from meteoric iron.
In fact, having discovered a more common source of iron than meteorites, people began using iron very quickly throughout the Near East, as iron weapons proved a lot tougher than bronze, which became relegated to the stuff of decorations – as iron had beforehand.