Archaeologists’ tricorder reveals objects’ ancient origins

Tricorder-style handheld scanners could help archaeologists uncover historical secrets without having to wait months for laboratory results.

Researchers from Sheffield University have adapted technology used to identify materials in scrap metal yards and docks, in order to determine the geographical origin of certain stone tools in just 10 seconds.

The portable scanner uses X-rays to analyse the chemical composition of ancient tools made from obsidian volcanic glass and identify where they came from, which could help archaeologists study the migration of groups of early humans.

Dr Ellery Frahm, who led development of the technique, said the scanner would enable archaeologists to make judgements about a dig site as artefacts were uncovered but also overcome the difficulty of taking discoveries out of a country for lab-based analysis.

‘Even though the analytical techniques are better than ever, it’s getting harder and harder to do these things in any meaningful way,’ he told The Engineer.

‘If you are dependent on lab-based chemical analysis you’re doomed to have an inconsequential number of articles available. You’ll have to make judgements based on the worst dozen artefacts that a country is willing to let go.’

The scanner is adapted from technology used to identify scrap metals.

The device uses a technique called X-ray fluorescence, whereby a material is bombarded with X-rays and subsequently emits photons with a specific energy signature depending on the chemical composition of the substance.

Similar handheld scanners are used in docks to quickly identify certain hazardous materials or to categorise grades of steel in scrap metal yards.

But archaeologists have traditionally used lab-based equipment or smaller scanners that analyse the entire composition of an artefact made from obsidian, which has been used to make cutting tools for almost 2 million years by humans and their ancestors.

Obsidian has been used to make tools for millions of years.

Frahm adapted the algorithms in a handheld scanner to look for certain chemical signifiers in order to to recognise the composition of different types of obsidian.

It then performs simultaneous checks against several location profiles to calculate which volcano out of a number of possible alternatives the sample originated from in just 10 seconds.

This should enable archaeologists to categories artefacts as they are discovered and learn how far the tool (and its owners) has moved from its origin.

Frahm admitted there was doubt among archaeologists as to how precise site-based analysis could be but that the device was designed to be used in difficult environments.