Nov 2, 2015

17th-Century Box's Contents Revealed by X-Rays

Powerful X-ray imaging techniques have allowed French archaeologists to see the inaccessible contents of a mysterious and badly damaged 17th century box.

Scientists were able to virtually reconstruct in astounding resolution the circular elements that could be seen through the broken lid of the very rusted box. Inside, the box contained a treasure of small clay medals and two pearls.

Measuring just 1.6 inches, the metal box was found during excavations at Grenoble’s Saint Laurent church. The artifact was buried alongside a corpse in one of the 195 graves dating from the 17th century.

The site has been at the center of archaeological investigations for the past 20 years, revealing more than 1,500 tombs and 2,000 objects dating as early as the 4th century AD.

The fragile box was first restored by the CREAM (Centre de Restoration et d’Etude Archaeologique Municipal) in Vienne, France. The work aimed to halt the oxidation process that was eating away the metal.

Despite their efforts, it was impossible to open the box. The archaeologists then brought the artifact to the European Synchrotron Radiation Facility (ESRF), which houses one of the world’s most powerful X-ray machines.

The box was scanned using synchrotron X-ray phase contrast micro-tomography. The technique produced high resolution 3D images of the inside.

“It was only supposed to be a small feasibility study to produce an image for an exhibition. However, the results were so astounding that it turned into a full scale research project,” ESRF scientist Paul Tafforeau, who carried out the experiments and produced the 3D images of the box, said in a statement.

The scan allowed Tafforeau and his team to virtually extract the two pearls and three medals, which appeared in poor condition and stuck together.

After the medals were digitally separated, the scientists applied rendering and 3D virtual lighting techniques to make the three medals visible in fine detail.

“This non-destructive investigations produced astounding results,” Renée Colardelle, the archaeologist in charge of the Saint Laurent church excavation, said.

On one medal, Christ can be seen on the cross with two figures standing at the foot of the cross. An engraving on the other side of the medal shows Christ’s resurrection. The scene is symbolized by a figure bearing a crown of thorns, with one leg out of the tomb.

The two other medals turned to be identical and damaged in different places.

A combination of the images obtained from the two identical artifacts made it possible to reconstruct the illustrations and even the inscriptions on the medals.

On one side, the scene of Christ’s baptism by Saint John the Baptist is visible, with the inscription “And the word became flesh.”

The reverse side shows the three wise men bringing gold, frankincense and myrrh to the infant Jesus seated on Mary’s lap. Given the state of preservation of the medals, the presence of Joseph behind Mary can be only assumed, said the researchers.

Read more at Discovery News

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