M.V. Moroz, O.L. Shvets, O.I. Novikova
Institute of Archaeology and Etnography of the Siberian Branch of the RAS, Novosibirsk
FIELD CONSERVATION OF ARTIFACTS EXTRACTED FROM PERMAFROST*
*The study was financed by the Russian Research Foundation grant (project No 14-50-00036)
Field studies on Ust-Voikar hillfort (Shuryshkary district of the YaNAO) involved opening of a permafrost level which contained a significant number of items made from organic materials - wood, birch bark, leather, plant and wool fiber, bone and antler. Over the period of 2012-2016 almost 4,500 artifacts have been obtained, of which 3,444 pieces (78%) were artifacts and fragments made from organic materials, All items taken out from the melting permafrost environment were oversaturated with water. After their extraction they became exposed to a strong negative effect of oxygen, as well as the changing temperature and light. Our first task was arresting of the destructive processes development: appearance of fungi and mold, overdrying and subsequent deformation of the items. Certain temporary conservation actions have been taken in the field laboratory immediately upon receipt of the finds.
Small wooden items were cleaned with dry brushes, then washed with water with the addition of 3% antiseptic solution (Lysoformin). Next step was drying - removal of water from the items in a displacing fluid (ethyl alcohol). When taken out of alcohol solution the items were, where necessary, fixed with bandages for preservation of their shape and stored until complete drying (preferably in a dark and cool place). Large size wooden items were cleaned as thoroughly as possible in field conditions from any contamination, carefully washed with water, covered with an antiseptic solution (5% Lysoformin), and packed while still wet in polyethylene film to prevent air access and over-drying.
Work with birch bark, leather and textile items was complicated by the fact that they were, as a rule, heavily creased, with outside deformations, tears on the inner structure of the materials and heavily contaminated. Small birch bark items were cleaned with dry brushes and washed with antiseptic water solution. After that they were sprayed with a 5% PEG-200 water solution. Whole deformed birch bark items were placed in cans with the aforementioned solution. The time of soaking the items in solution depended on the rate of absorption by the inner material structure of a conservation solution and could take up to three days. Owing to the polymer the birch bark acquired plasticity which allowed to restore the shape of the items while they were still wet and preserve it with the help of soft or hard frames.
The most heavily contaminated items were fabric sherds and various braided items (mats, ropes). Fabric sherds were carefully cleaned with dry soft brushes, placed on a net and covered with rich neutral detergent foam with water. In 30-40 minutes the foam was washed away with sprayed water. Then the piece would be turned over and the procedure repeated. At the final stage a small quantity of an antiseptic was added to the washing liquid. After that the textile items were spread on a glass surface and dried under a press. For large size fabric pieces and the heavily creased ones a low-molecular PEG–200 could be used as a conservation agent.
Prompt use of field conservation techniques made it possible to smooth out the items, temporarily strengthen the inner structure of materials, and restore the items' shape without any additional damage to preserve them for the consequent full scale restoration works in the stationary laboratory conditions.