Conservation and Restoration of a Sample of Human Skeletons Belonging to the Iron Age Museum of Tabriz

Bones and human skeletal remains are among the most important materials found in many archeological excavations. Bones are composite materials consisting of organic and inorganic parts. Minerals constitute 70% of the dry weight of bones and organic substances the rest. This valuable material is degraded by environmental factors and microorganisms and its physical and mechanical properties are lost. Therefore, it is necessary to preserve bones. The Iron Age Cemetery of Tabriz with its buried human remains and the items found inside the tombs in the natural environment has been converted into a museum site. This paper describes the preservation and reconstruction of a sample of human skeleton belonging to this museum site taking into account the available pictures related to the excavation and removal of the factors damaging the skeletons. The results of the tests on soil EC, type of soil granulation and pH, the qualitative identification of the dissolved salts (anions), and the determination of the moisture content in the burial site indicated that the soil had a high moisture content, strong saline salts, and a loamy texture. The soil and skeleton had neutral (weakly alkaline) pH values. After carrying out the necessary studies, the skeleton was transferred to the workshop to be preserved and reconstructed and the soil in the bottom of the tomb was removed and desalinated with distilled water. Nano hydroxyapatite was used to improve the strength of the bones and Moldano and Simacryl R83 to reconstruct the lost parts of the skeleton. Plexiglas was employed as the insulator in the bottom of the tombs to cope with the rising moisture content.