Science&Tech A rare radioactive ‘alien alloy’ used by bronze age Swiss craftsman Posted on August 3, 2023 4 min read Share on Facebook Share on Twitter Share on Google+ A small find at an excavation in Switzerland turns out to be much more interesting than archaeologists first thought. A more than 3,000-year-old weapon excavated in Switzerland in the 19th century turns out to be made of a very special material. The tiny arrowhead was found during the excavation of a prehistoric pile dwelling in Möringen, along lake Biel. But only now have archaeologists from the Naturhistorisches Museum Bern and others studied the Bronze Age weapon closely using advanced X-ray technology. And it turned out that the little thing has had quite a journey to say the least. The researchers think the arrowhead was made of iron from a piece of cosmic material that survived its journey through the atmosphere and impacted the Earth’s surface: a meteorite. A skilled craftsman, probably from the late Bronze Age, decided to forge a deadly weapon from the alien material. Rare find Experts assume that almost all Iron Age tools are made of iron from meteorites, and archaeologists have previously found similar objects in Greece, Turkey, Syria, Lebanon, Iraq, Egypt, Iran, Russia and China. In central and western Europe, however, such finds are and a lot rarer, and only a few have been recorded so far. Another peculiarity is that the meteorite may have struck surprisingly far from the excavation site in Switzerland. The researchers were able to determine this by examining the composition of elements in the material using a method in which the weapon is irradiated with X-rays. The rays reflected from the arrowhead are then analysed. The X-ray method revealed that the arrowhead was composed of iron, nickel and a radioactive isotope of the element aluminium, aluminium-26. Extensive trade network Most interestingly, the mix of metals in the iron arrowhead did not match the meteorites found near the settlement in Switzerland. The researchers suspect that the iron came from a specific group of meteorites, known as IAB meteorites. The archaeologists looked at three large, known IAB meteorites that landed in Europe and discovered that the source of the iron is believed to be the Kaalijärv meteorite, which struck what is known now as Estonia around 1500 BC- 1,600 kilometres from the site in Switzerland. According to the researchers, the arrowhead therefore also says something about the extensive network of trade routes that must have existed thousands of years ago.
