Detection of the cosmogenic isotope aluminum-26; nickel, cobalt, germanium and gallium concentrations; and the presence of two minerals called kamacite and taenite clearly indicate the meteorite nature of the ancient arrowhead from the Bronze Age settlement in Mörigen, Switzerland.
Morigen arrowhead. Image credit: Thomas Schüpbach.
A researcher at the Natural History Museum of Bern and the University of Bern, lead author Dr. “Metallic iron was available to humans in the rare form of meteorite iron before smelting of metal from oxide ores began,” said Beda Hofmann and colleagues.
“The use of meteorite iron for the manufacture of objects in pre-Iron Age times in Eurasia and North Africa is known from find complexes in Turkey, Greece, Syria, Iraq, Lebanon, Egypt, Iran, Siberia, and China.”
“Meteoritic iron artifacts are very rare in Central and Western Europe and have so far been limited to two sites in Poland: the two Czestochowa-Rakowa bracelets and the Wietrzno ax.”
In their research, archaeologists examined an unusual iron arrowhead from the collections of the Bern History Museum.
The artifact was found in the 19th century at the Late Bronze Age lake settlement of Mörigen in Switzerland.
“The Mörigen pile dwelling has been known since 1843, it was first sampled by fishermen and excavated in 1873-1874,” the researchers said.
“The site is located just 4-8 km southwest of the large Twannberg iron meteorite minefield with more than 2,000 individual finds totaling 150 kg.”
The Mörigen arrowhead has a mass of 2.9 g and dimensions of 3.9 cm (length), 2.5 cm (width), and 0.3 cm (maximum thickness).
The object consists of rust-coated ferrous metal with a very distinctive laminated texture. In some areas fine-grained sediment is adherent.
“The arrowhead is a very flat object (aspect ratio 15.1, 20 after correction for increased thickness due to oxidation),” the scientists said.
“Primary shapes of meteoritic iron are never that flat, even in the case of ‘shrapnel’ (parts formed by explosive fragmentation on impact).”
“The flat aspect of the object must have resulted from artificial deformation of an initially less flattened object due to cold or hot working.”
The authors examined the Mörigen arrowhead using a combination of several non-destructive-only methods, including muon-induced X-ray emission spectrometry and high-sensitivity gamma spectrometry.
Elemental composition (7.10-8.28 wt% nickel, 0.58-0.86 wt% cobalt, 300 ppm germanium), presence of nickel-poor and nickel-rich iron phases, kamacite (6.7 wt% nickel) and the presence of taenite (33.3% by weight nickel) and cosmogenic aluminum-26 confirmed the meteorite origin of the artifact.
They were also surprised to find that the Mörigen metal did not come from the nearby Twannberg iron meteorite minefield.
“The Mörigen arrowhead should be derived from a large (at least 2 tons pre-atmospheric mass) IAB iron meteorite based on gamma spectrometry and elemental composition,” they said.
“Among the large IAB meteorites from Europe, three have a chemical composition consistent with the Mörigen arrowhead: Bohumilitz (Czech Republic), Retuerte de Bullaque (Spain) and Kaalijarv (Estonia).
“Kaalijarv is a large meteorite that formed a series of impact craters on the island of Saarema in Estonia.”
“As a result of the explosive impact, most of the meteorite mass (possibly several 100 tons) was destroyed, and the recovered meteorite fragments are mostly small ‘shrapnels’ from main mass destruction.”
“Such a small fragment could be the source of the arrowhead, but separation from larger masses is also possible, as is well documented for the Cape York meteorite.”
“The total recovered mass of Kaalijarv is only on the order of 10 kg,” they added.
“According to three independent studies of organic matter from the floor of lake sediments and under eruptions, the impact most likely occurred between 1870 and 1440 BC, namely the Bronze Age.”
The discovery shows that iron meteorites were used and traded in Europe around 800 BC and even earlier.
“Parts of the Kaalijarv meteorite may have been traded in the same ways as amber from the Baltic region,” the archaeologists said.
His articles will be published in the September 2023 issue. Journal of Archaeological Sciences.
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Beda A. Hofmann take meat. 2023. A meteorite iron arrowhead and its possible source from a Late Bronze Age settlement in Mörigen, Switzerland. Journal of Archaeological Sciences 157:105827; doi: 10.1016/j.jas.2023.105827
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