Notice catalographique « Examining the effect of relative humidity on mammoth molars »
- Titre
- Examining the effect of relative humidity on mammoth molars
- Auteur ou éditeur
- Doyle, Daniel
- Queen's University
- Lieu de publication
- Kingston, Ontario
- Maison d'édition
- Queen's University
- Date de publication
- 2015
- Collation
- iv, 29p; ill. (chiefly colour)
- Résumé
- Museum and natural history collections are very sensitive to fluctuations in relative humidity (RH). Due to a high degree of structural anisotropy, mammoth molars are potentially damaged by such fluctuations. Upon excavation, mammoth molars often undergo rapid acclimatization to the ambient RH. The main focus of this research was to quantify what occurs to mammoth molars at low RH, and to investigate whether permanent changes take place or if previous cracking is able to accommodate RH fluctuations. A research project conducted by Samantha Fisher in the Art Conservation Program at Queen’s University, Kingston, Ontario, in 2014 on mammoth molars found that cracks widen and extend after exposure to 75%RH, cracks continue to extend after a drop to 35%RH. It was also found that cement adsorbs and desorbs faster than enamel, and that Fourier transform infrared spectroscopy shows the presence of hydroxyapatite and water with some carbonate and fluoride substitutions. As the molars used had already undergone humidity cycling, there were no significant changes to cracks observed during the experiment. To further understand the changes which occur during significant drops to low RH, such as during the initial excavation and drying of molars, a single cycle was undertaken from ambient RH to a low 11%RH using a lithium chloride salt. Weight changes indicating the desorption of water from the teeth were measured to better understand the internal moisture change, and to identify when the molars reached equilibrium. The resulting dimensional changes and crack propagation were measured using ImageJ analysis software, as well as physically measuring the cracks.
- Overall, an increase in the crack ratios and dimensions was measured, as well as a possible joining of previously separate cracks. A measurable loss of material also occurred from the three molars, including powder and fragments. It is certain that exposure to the 11%RH environment has produced an irreversible change in the molars. This research is only one of a very limited number of studies into the effects of relative humidity on natural history collections. As such, a survey of current storage conditions for natural history collections was undertaken, to better understand current practices and propose preventative steps. The survey found that many mammoth molar collections undergo fluctuations of RH +/-10% outside the normal storage conditions which last longer than one week. It is certain that these environments cause additional damage to mammoth molars comparable to those observed in this study.
- Notes
- Research project submitted to the Department of Art in conformity with the requirements for the Degree of Master of Art Conservation
- Langue
- English = Anglais
- Sujet
- Natural history collections - conservation and restoration
- Museums - Climatic factors
- Museum conservation methods
- Collections de sciences naturelles - conservation et restauration
- Musées - Facteurs climatiques
- Musées - Méthodes de conservation
- Pays
- Canada
- Type de document
- Monograph = Monographie
- Serial = Publ. en série
- Localisation
- AM 141 D69 2015
- Clé
- 17451
- Collection
- Catalogue