London, July 16 (ANI): A new analysis has concluded that the world's oldest tattoos, belonging to Otzi the 5300-year-old Tyrolean iceman, were etched in soot.
The simple tattoos may have served a medicinal purpose, not a decorative one, Maria Anna Pabst, a researcher at the Medical University of Graz, Austria, told the New Scientist.
Pabst trained optical and electron microscopes on biopsies of Otzi's preserved flesh.
Clothing would have obscured most of the designs, which are of crosses and bands of lines. Some are located near acupuncture points.
Alpine climbers discovered Otzi near the Italian-Austrian border in 1991.
Since then, scientists have analyzed his clothing, diagnosed him with various ailments - arthritis, back and stomach problems - and even sequenced his mitochondrial genome.
To work out what Otzi's tattoos were made of, Pabst's team applied light and electron microscopes to minutely thin sections of several tattoos as well as a non-tattooed flesh from his inner thigh.
A close look at his tattooed skin revealed numerous fine particles, interspersed with elongated crystals.
Chemical analysis indicated that the particles were made of double-bonded carbon atoms found in soot, while the crystals were made of silicate.
His tattoo-free skin, on the other hand, showed no trace of soot particles.
"Otzi's "ink" could have been scraped off silicate-containing rocks surrounding a fireplace," Pabst said.
"When you look at the b taken out - you can't see anything that tells you how the tattoos were made," she added.
Perhaps, Otzi's brethren used thorns to pierce the skin deeply enough to inject a soot ink, according to the researchers. (ANI)