The action of weathering on burned bone:
an Experimental Approach
The alteration of bones following exposure to weathering is today well known, but it is possible that burned bones do not suffer the same type of changes since their physicochemical properties are modified by combustion. A series of experiments has been carried out with the aim of better understanding these reactions. These experiments form part of a more widespread attempt to better understand the impact of taphonomic agents on burned bones in order to estimate the distortions between bone material originating from experimental combustion and the fossil material.
Five experimental series resulting from the combustion of fresh cow humeri were exposed for eighteen months to weathering in a Mediterranean context. Several criteria were observed in order to highlight the impact of this exposure on the burned bones: degree of fragmentation, loss of bone mass, alteration of bone surface, influence of the degree of combustion (carbonised vs charred) and of the bone tissue (spongy vs compact) on the preservation of the material.
The results of these experiments mainly show a high fragmentation of the material (the small burned bones being in the majority), associated with a reduction in bone mass. In addition, spongy and charred bones have an increased sensitivity to the action of weathering, leading to their destruction. A preferential preservation of charred compact bone is thus expected.
To cite this article
Gerbe M., 2010 – The Action of Weathering on Burned Bone: an Experimental Approach, in Théry-Parisot I., Chabal L., Costamagno S., The taphonomy of Burned Organic Residues and Combustion Features in Archaeological Contexts, Actes de la table ronde, 27-29 mai 2008, CEPAM, P@lethnology, 2, 185-196.
Reflections on the potential
for preservation of burned bone based on the material
from Saint-Antoine (Vitrolles, Hautes-Alpes)
Maryline RILLARDON, Jean-Pierre BRACCO
The faunal assemblage from the open-air site of Saint-Antoine at Vitrolles (Hautes-Alpes, Epigravettian) has yielded an atypical composition of burned bones (NRT = 23 %), being composed mainly of charred compact bones. While in an experimental context a high proportion of charred bones is typical of the use of skeletal remains as fuel, their representation in archaeological contexts is generally low, particularly in comparison to that of the less intensely burned elements. Contrary to this general principle, the Saint-Antoine deposit shows a strong representation of charred bones in a difficult taphonomic context characterised by an acid sediment and by the intensive action of different taphonomic phenomena (weathering, sediment compaction, dissolution). The high representation of charred bones seems to result from a combination of various factors, including the purpose of the combustion (camp maintenance and/or use as fuel) and their intense fragmentation, together with a higher preservation potential for burned bones (compact and spongy), including charred bones, compared to unburned bone elements when they are buried in acid sediments.
To cite this article
Rillardon L., Bracco J.-P., 2010 – Reflections on the Potential for Preservation of Burned Bone Based on the Material from Saint-Antoine (Vitrolles, Hautes-Alpes), in Théry-Parisot I., Chabal L., Costamagno S., The taphonomy of Burned Organic Residues and Combustion Features in Archaeological Contexts, Proceedings of the round table, May 27-29 2008, CEPAM, P@lethnology, 2, 197-208.
Taphonomic implications of the use
of bone as fuel
This paper explores the effects of the use of bone as fuel on archaeological skeletal part representation. Faunal data from the Paleolithic site of Saint-Césaire show that this activity may present an archaeological signature similar to that of differential preservation. The bones most frequently burned at Saint-Césaire are also those that are the least dense and that contain the most grease. The analysis of faunal remains from Saint-Césaire also suggests that spongy bone fragments from small-bodied and large-bodied taxa are subject to differential identification.
To cite this article
Morin E., 2010 – Taphonomic Implications of the Use of Bone as Fuel, in Théry-Parisot I., Chabal L., Costamagno S., The taphonomy of Burned Organic Residues and Combustion Features in Archaeological Contexts, Proceedings of the round table, May 27-29 2008, CEPAM, P@lethnology, 2, 209-217.