Handling of bloc recoveries from older excavations in the Bavarian State Office for Preservation of Archaeological Monuments
In 2012 the conservation of an infant grave from the 20th Century was realized. The whole grave was recovered in a bloc during an excavation in 2002, where several burials were found in the St. Andreas church in Vohburg in the middle of Bavaria and archived in the State Office in Ingolstadt.
A conservation project was started during a reorganization of the Bavarian State, as the corpus of finds had to move to another State Office. In the course of this move the condition of the finds were evaluated and it was possible to intervene when the deterioration couldn’t be stopped anymore by preventive conservation engagements. In a two year project especially uninvestigated bloc-recoveries in very bad condition where focused, just like the infant grave. The aim of the conservation efforts were to separate the materials for a better handling in repository and extract all information before they were lost for ever.
The surface of the bloc-recovered infant grave was consolidated on excavation with an Acrylic media; parts of the stony earth have been drifted apart and mold affects a further damage. All the organic materials were in a very bad condition and nearly rotten. Despite this bad initial situation it was possible to find out a lot about this infant burial. What has to be highlighted is the costume with the bobbin lace made of metal threads, which give notice about the border of it. With analytic methods it was possible to identify the materials. The appearances of the flat and twisted metal threads or of the fine textiles were changed by corrosion and mold. The fibers, which were modified and coated by hyphae of the mold, could only be identified by using scanning electron microscope. With EDX measurement it was possible to identify the metal of twisted strips which were made of copper that was coated with a zinc-layer for a golden appearance. This helped to find out the technique, which is an indicator for the industrial revolution for that time.
SEM pictures on the left side from top to down:
1. Break through a metal thread
2. Corrosion product on metal thread
3. Wooden remains of the coffin
4. Marks from the bast fiber of one of the textiles
Because of the dislocated parts it was difficult to understand the context of the burial. A detailed mapping of the organic fragments helped to get a picture of the costume. By using the photos in the software Adobe Photoshop the recovery excavation was documented, in order to describe the context of the fragments. It was also possible to make a digital reconstruction of the costume which serves as a basis for discussion and should help further archaeologists to date the finds.