Early bone diagenesis in temperate environments: Part I: Surface features and histology

Abstract Early diagenesis, spanning the time a few years after death, is crucial to later fossilization, because the former may determine the success of the latter. The external environment in which bones (and fossils) have been altered is critical to early diagenesis and fossilization processes. Alteration of bones by the former may determine the successful fossilization of animal bones and their eventual preservation as part of a fossil assemblage. A long term actualistic experiment took place in Neuadd (Wales, UK) from 1976 to 2006 with the monitoring of approximately 100 animal carcasses. The Neuadd bone collection is derived from natural deaths of domestic and wild animals, the carcasses of which were left in situ and exposed under natural conditions in a series of upland environments in central Wales. Here, we report on a sample of this extensive collection, investigating possible associations between environmental or post-depositional situations and physico-chemical traits at early stages of diagenesis. One of the main agents of bone structure alteration and chemical diagenesis is bacteria, while another may be non-vascular plants. Results obtained so far suggest correlations between surface and histological modifications that are present in temperate environments, but geochemical and collagen contents need a more careful study. Modifications of the surface and histology of the bone are treated in detail and we conclude that some assumptions traditionally considered of relevance (such as soil acidity, decay conditions and bacterial activity) are less important or inadequately defined. The significance of this for diagenesis studies is discussed and correlations with indices of preservation of collagen, DNA, crystallinity, chemical composition and stable isotope signals of these specimens of the Neuadd collection are outlined, but more detailed descriptions will be presented in forthcoming papers.