Bone Degradation in a Compost Heap

This paper describes an experiment set up in 1987 to investigate the decomposition of animal bones, mainly from smaller species, within an accumulating dump of organic refuse. The project forms part of a wider comparative study by the author into the degradation of mainly smaller animal bones (Nicholson, 1991, 1992, 1993, 1996a) with the aim of modelling taphonomic processes and providing data to enhance our understanding of bone preservation on archaeological sites. Following 7 years of burial within an accumulating domestic compost heap, a suite of mammal, bird and fish skeletons was excavated and examined for evidence of morphological, histological and chemical modification. By comparison with similar suites of bones buried and excavated at around the same time, most of the bones from the compost heap were very well preserved. It is argued that this may be a consequence of the cross-linking of collagen with humics from the soil, resulting in a structure resistant to enzymatic attack.