Children’s grave recovered by flash freezing

Children’s grave recovered by flash freezing

The children’s grave is frozen with liquid nitrogen and lifted in a block for transport to the laboratory. (Image: BLfD)

A ten-year-old, armed and buried with a dog: Archaeologists report on an early medieval grave in southern Germany, which has now been recovered in the block for further investigation. A newly developed technology was used: To protect the sometimes filigree remains from damage, the team gave the children’s grave an ice armor using liquid nitrogen.

As is so often the case, the development of a new building area was at the beginning of a story of archaeological discovery: In the town of Tussenhausen in the Unterallgäu district, traces of ground monuments came to light and so the experts from the Bavarian State Office for the Preservation of Monuments (BLfD) quickly appeared at the site. There they came across the traces of a grave which, according to the dating, dates back to the 7th century AD. It was embedded in the remains of the wall of a square, eight-meter-wide building that dates back to Roman times. Apparently these structures were used as burial places in the early Middle Ages.

An armed boy with a dog

The archaeologists discovered the bones of a boy in the grave. He still had milk teeth, so they assume that he could hardly have been more than ten years old. The cause of his death has yet to be clarified. This also applies to the dog that was buried with the boy – the remains of the dog were found by the experts in the area of ​​the dead man’s feet. Other previous finds show that it was apparently a child of the upper class: the boy was given a sword with a belt decorated with gold fittings, Christian symbols made of gold and other treasures. Including silver bracelets, spurs and a bronze cymbal.

Traces of leather and textiles, which have mostly not been preserved in other graves, are also particularly exciting. As the BlfD reports, the extraordinary condition is due to the fact that the stone structures sealed the burial chamber well for almost 1300 years. This meant that hardly any moisture and sediment could penetrate the coffin. “This funeral is a stroke of luck for us, especially because so many scraps of fabric have been preserved. They promise highly interesting insights into the early medieval world of fashion, ”says Mathias Pfeil from the BlfD. “Our intensive research in recent years gives an idea of ​​the importance of high-quality textiles and decorated leather for the representation of the status in the early Middle Ages. From the finds that have now been recovered, we expect new insights into the textiles used at the time and how they were worn, ”says the conservator.

Rescued frosty and transported away

But as the BlfD further reports, of all things the good state of preservation of the finds poses a special challenge: Without the stabilizing effect of deposits from the ground, they are extremely sensitive and threaten to break when they are recovered. For this reason, the restoration team used a shock freezing process in order to gently lift the whole child’s grave out of the ground and transport it away. To do this, they moistened the contents of the grave chamber layer by layer with water and frozen these layers with liquid nitrogen at minus 196 degrees Celsius. The sudden cooling ensured that the applied water hardened without the formation of destructive large crystals, explain the experts. Then the whole block could be pulled out of the ground by a crane.

The icy treasure is now in a cooling chamber of a laboratory of the restoration workshops of the Bavarian State Office for the Preservation of Monuments in Bamberg. There, the ice is to be melted under finely controlled conditions so that the filigree structures can then be examined under laboratory conditions. So it will be interesting to see what the experts can find out about the early medieval children’s grave with dog.

Source: Bavarian State Office for Monument Preservation

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