Quantifying Degradation of Archaeological Bone In Situ and in Museum Storage: A Comparison Between Environment and Degradation over Forty-Three Years for Bones from the Aasivissuit Site, Western Greenland

Аннотация

Degradation of archaeological bone is a complex process that is influenced by both intrinsic and extrinsic parameters. Here we study the decay of bones recovered from a large midden at the Inuit summer hunting camp, Aasivissuit, in West Greenland, dating from 1200 CE to 1950 CE. The site was partly excavated in 1978 and revisited for further excavation in 2021 to study changes in the materials’ state of preservation, both in situ and in museum storage. The state of preservation was described visually for several hundred bones from both investigations. The reactivity of 34 caribou bones was measured at −5˚C, 1˚C, 5˚C, 10˚C, and 15˚C, and compared to their density, composition, and histological decay pattern. Environmental monitoring on site included soil type, pH, porosity, water content, and temperature, while monitoring in storage included relative humidity and temperature.

The observed degradation patterns and changes that occurred in the period 1978 – 2021 in situ and in museum storage are explained. Furthermore, current climate change predictions are used to evaluate what may happen to the site in the future. Findings include: 1) the bones preserved in situ showed little change since 1978, while the excavated bones in museum storage were more degraded; 2) the decay pattern for the bones is well correlated with environmental conditions; 3) the reactivity of wet bone measured as oxygen consumption was largely controlled by bone density and temperature; 4) loss of organic and mineral components of the bone under current conditions can be estimated using numerical models; and 5) continued in situ preservation under current and future climate conditions is considered feasible.