Experimental effects of bone size and temperature on bone diagenesis

In the ground, bone undergoes chemical and physical changes which affect its preservation. This fact has important implications for dating and other analytical procedures involving bone, as well as faunal analysis where differential preservation of bones of different species may affect conclusions regarding the relative significance of an animal to the economy of a given society. The diagenic processes in bone range from minor changes in the bone protein to complete structural and chemical breakdown.Using fresh cow bone, we conducted laboratory experiments which simulate the effect of temperature and bone size on the rate and nature of bone disintegration in archaeological sites. Temperature influences the rate of chemical change, and bone size and density affect the accessibility of the molecular constituents of bone to extrinsic chemical reactions. These findings clarify the importance of two well-known concepts in bone taphonomy. (1) The rate of chemical breakdown in bone tissues is related to the proximity of a given unit of tissue to the bone surface. This means that, in archaeological bone samples, tissue near the surface may be different chemically from tissue away from the surface and great care is necessary in choosing and preparing bone samples for analytical procedures. (2) In general, small bones are not as well preserved as large bones, therefore small animals are likely to be underrepresented in faunal assemblages.     

Bone surface modifications in zooarchaeology

Cutmarks made by stone tools, conchoidal flake scars from hammerstone percussion, carnivore tooth marks, striations from sedimentary abrasion, and other surface modifications on bones from archaeological sites constitute a crucial body of evidence for investigating the role of human behaviors and of nonhuman taphonomic processes in site formation. This paper describes the various kinds of bone surface modifications produced by humans and by nonhuman processes and assesses the current status of bone surface modification studies with regard to such issues as the need for greater analytical standardization, the selection of instruments for examining bone specimens, tactics for identifying the origins of marks on bones, and strategies for inferring human behaviors.     

Are Teeth Better? Histological Characterization of Diagenesis in Archaeological Bone–Tooth Pairs and a Discussion of the Consequences for Archaeometric Sample Selection and Analyses

Teeth are often the preferred source material for isotopic and genetic assay involving ancient biomolecules. The assumption is that dental tissue preserves better due to its anatomically protected location, the enamel cap, and lower porosity compared to bone. However, this assumption has not been widely tested. Some similarities in diagenetic processes are to be expected due to similarities in structure and chemical composition of dentine and bone. This has led to the suggestion that bone can be used as an indicator of dental preservation, as a pre‐screening technique in the selection of suitable samples for biomolecular studies. Thus, direct testing of the correlation between bone and tooth preservation and diagenesis is needed. This paper reports the results of the histological characterization of diagenetic alterations within 25 human femur–tooth pairs, from a Medieval to modern (AD 1850) cemetery in Eindhoven, the Netherlands. The results showed that teeth do indeed preserve better overall, but not always, and that this was dependent on the main diagenetic factor(s) at the burial location. Furthermore, good correlations are found between the microstructural preservation of bone and teeth; similar processes of decay were observed within bone and teeth of the same individual. Overall, the study demonstrated that histological analysis of bone is useful for the identification of degradation processes that affect biomolecular preservation in skeletal material. In this way, sample selection and analytical strategies can be optimized. Copyright © 2013 John Wiley & Sons, Ltd.     

The bioerosion of bird bones

This study presents a synthesis of the evidence for modern archaeological, and palaeontological bioerosion of vertebrate tissue. It describes the first evidence for the bioerosion of modern, archaeological and fossil bird bones. A new form of bone bioerosion, known as Hackett tunnels, is defined. The bioerosion of vertebrate tissue by cyanobacteria and algae in modern marine and lacustrine environments is also described. Archaeological evidence indicates that the destruction of bone by bioerosion occurs in other terrestrial environments, such as cave deposits and middens. Bone from marine and lacustrine environments that appears to be macroscopically well preserved can have large amounts of microscopic fabric destruction. © 1997 John Wiley & Sons, Ltd.     

The use of soil chemistry data to address post-mortem diagenesis in bone mineral

The soluble and exchangeable ions for a soil profile from the Roonka archaeological site. Lower Murray Basin, South Australia, are compared with the total elemental content of the soils. Since the chemical composition of post-mortem ionic substitution phases and secondary minerals in archaeological bone will depend on the availability of ions to the soil solution under field conditions, it is suggested that models addressing diagenesis in bone employ soluble and exchangeable ions rather than total elemental soil data.     

Preservation of bird bones: erosion versus digestion by owls

Surface damage to bird bones from pellets of three species of owls (S. aluco, A. otus and B. bubo) was compared with that of bird bones exposed to weathering and soil corrosion (Záskogo Cave in the Western Balkan Mountains, Bulgaria and Ciemna Cave, southern Poland). Scanning electron microscopy and light microscope examinations indicate that the effects of weathering of bird bones (extensive pitting and flaking away on whole bones, holes with sharp edges, depressions with rough bottoms and sharp edges of breakage) are distinguishable from those of digestion (rounding of hole edges on articular ends and sometimes on shafts, rounding of breakage). However, soil corrosion may produce similar rounding to that of digestion, which may hamper taphonomic interpretations of fossil assemblages. Two stages of weathering in bird bone are distinguished. Generally, the kind of damage done to bird bones is similar to that done to mammalian remains. Taphonomic studies of fossil bird remains should take into account a combination of features, including surface damage, fragmentation and possible chemical alterations of bone tissues. © 1997 John Wiley & Sons, Ltd.     

Fragmentation of Bird Bones in Food Remains of Imperial Eagles (Aquila heliaca)

Fragmentation of bird bones in pellets and uneaten food remains of imperial eagles (Aquila heliaca) was studied. The degree of fragmentation was higher than that produced by owls and lower than that in gyrfalcons. There were significant differences between pellets and uneaten remains in the survival of bones and their fragmentation. © 1997 by John Wiley & Sons, Ltd. Int. J. Osteoarchaeol., 7 : 165–171 (1997) No. of Figures: 0. No. of Tables: 5. No. of References: 21.     

Volume density of South American camelid skeletal parts

This paper provides a set of volume density values for skeletal parts of lama (Mammalia, Artiodactyla, Camelidae). The method by which these values were obtained is described and compared with published data of densitometries made on cervids, showing a high positive correlation between the bone densities of the two artiodactyls. The camelid bone density data are used to discuss the interpretation of skeletal patterning in an Andean archaeofaunal assemblage.     

‘Well,Sextus, what can we do with this?’ The disposal and use of insect-infested grain in Roman Britain

Abstract

Beetle (Coleoptera) pests of stored products such as the granary weevil may have entered the archaeological record by various routes, including: (1) deliberate dumping, and usually burial, of spoilt grain with the aim of preventing further infestation of grain in storage; (2) the use of infested grain as human and animal food; (3) the incorporation of infested grain and living or dead grain pests into deposits by accident and by reworking. It is suggested that these routes, although outlined specifically for beetle grain pests, can stand as a model for the way other insects and biological remains became incorporated into the archaeological record. It also is suggested that the identification of these different depositional routes depends strongly on taking a multi-proxy (‘indicator group’ or ‘indicator package’) approach to the archaeological and biological record of urban sites.     

Cooked Bones? Method and Practice for Identifying Bones Treated at Low Temperature

Is it possible to determine low‐temperature cooking in archaeological bones? The indirect exposure of bones to fire at low temperature (≤ 100 °C), linked to cooking, produces macroscopic modifications on these bones. These modifications have not been clearly or systematically described previously. Instead, physicochemical changes at nanometric level are only now beginning to be understood. In this paper, our principle aim is to explore new methods and techniques that correlate macroscopic features such as smoothness or light transparency with physicochemical characterization results that could aid towards detecting cooked bones in the archaeological record. This study then selected 11 archaeological samples, both human and non‐human. Bones were considered to be thermally treated or not, on the basis of macroscopic criteria. Complementary characterization techniques were used to study morphology (scanning electron microscopy and small angle X‐ray scattering), structure (X‐ray diffraction and transmission electron microscopy), local composition (energy‐dispersive X‐ray spectroscopy) and texture (gas adsorption). Indeed, fractal dimension, particle size, crystalline percentage or specific surface area may well explain some of the macroscopically observed modifications on these samples. The possibility that such apparent modifications may also be due to diagenesis is also considered. From an archaeological point of view, the results are promising. Our characterization of human and non‐human bones demonstrates that physicochemical techniques are complementary and provide good criteria against which to distinguish boiled from un‐boiled archaeological samples. Copyright © 2013 John Wiley & Sons, Ltd.     

In situ Preservation Solutions for Deposited Iron Age Human Bones in Alken Enge,Denmark

The rich mass deposition of Iron Age human bone material from the Danish site, Alken Enge, is extraordinary not only from an archaeological perspective but also from a preservation point of view. The main find is situated in a waterlogged, anoxic environment which provides excellent preservation conditions and therefore enables in situ preservation of the human bones. However, major differences in local environmental conditions challenge an in situ preservation of the entire site area as parts of the bone material presently deteriorate. In this paper, a multi-proxy environmental monitoring approach is used to document threats and to suggest the best preservation solution for the archaeological finds, whether in or ex situ.     

Infant taphonomy

In almost all living creatures, in Primates as well as in seventeenth–eighteenth century human populations, a high infant mortality is the rule; therefore, the scarcity of children's bones in cemeteries is suspicious from a demographic point of view. Though possible in some cases, sociological causes appear less important than the peculiar behaviour of infants' bones in the tomb. This paper examines the physico-chemical properties of infants' bones and their consequences for the preservation of archaeological samples; it proposes a new way of approaching distributions at death in the past. © 1997 John Wiley & Sons, Ltd     

‘Not All That Is White Is Lime’—White Substances from Archaeological Burial Contexts: Analyses and Interpretations

Archaeological burial contexts may include a variety of white substances, but few analyses have been published. This study reports on the physico‐chemical characterization of such residues from seven archaeological sites. It is often assumed that white materials from burial contexts are lime. Our findings demonstrate that they can be gypsum, calcite (chalk), aragonite, brushite, degraded metal, natural (gum) resins or synthetic polymer–based products. These may be present as the result of diagenetic processes, funerary practices or modern contamination. This paper provides an analytical approach for the holistic investigation of white materials encountered in burial contexts.