BONE POROSITY AND THE USE OF MERCURY INTRUSION POROSIMETRY IN BONE DIAGENESIS STUDIES*

Porosity measurements made on archaeological bones have revealed very-close relationships between changes in the porosity, remaining protein content and mineral alterations. The results have important implications for models that attempt to quantify the rates and extent of chemical reaction between bone and its geochemical environment. We report here on a novel application of an established technique, mercury intrusion porosimetiy, to investigate in more detail the pore size distribution of archaeological bones. Mercury intrusion porosimetry measures an ‘intermediate’range of bone porosity, ‘mesoporosity’, and produces data which permit the observation of significant structure characteristics in the porosity of modern laboratory altered and diagenetically altered bones.     

An assessment of the value of bone density measurements to archaeoichthyological studies

This paper reviews the meaning of the term ‘density’ and the problems associated with the methods of density determination for animal bones in archaeology. It has often been assumed that density is the intrinsic property of most influence in controlling the rate of a bone's decay. Values for whole bone density have been published only for large mammal bone, however. Fish bone appears to be particularly vulnerable to decay, and usually a restricted range of skeletal elements are recovered from archaeological sites. The object of this study was to examine the relationship between fish bone density and the ability of the bone to survive on occupation sites and in archaeological deposits. A set of ‘density’ measurements was established for the bones of cod (Gadus morhua). The usefulness of these measurements as a predictive tool in archaeoichthyological studies is assessed. It was found that ‘density’ as measured did not explain adequately the relative survival of skeletal elements after mechanical abrasion and weathering, or within archaeological deposits.     

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones.     

Transition from hunting to animal husbandry in Southern,Western and Eastern Finland: new dated osteological evidence

The beginning of animal husbandry in Finland is one of the most debated topics in Finnish archaeology. For this study a total of 69 bone materials from archaeological sites in Southern, Western and Eastern Finland, dating from the Middle Neolithic to the Early Metal Period, were analysed: 52 represented identifiable animal bones. These data were complemented with those from previously analysed bone materials. A total of 19 domestic animal bones were radiocarbon-dated to determine their connection with a particular cultural period. However, 13 of them proved to belong to the historical and not the prehistoric period, emphasizing the importance of radiocarbon-dating and context awareness when interpreting prehistoric bone materials. Among the radiocarbon-dated material were the oldest dated sheep, cattle and horse bones in Finland. The oldest radiocarbon-dated domestic animal bone in Finland, from sheep or goat, derives from the Late Stone Age Kiukainen Culture site, while cattle and horse bones date to the Bronze Age. This is later than expected. However, the available material does not exclude the possibility that some animal husbandry was practised in Finland earlier. Nevertheless, domestic animal bones are rare in samples dated to the cultural periods studied, while hunting and fishing represented important subsistence activities.     

Bone diagenesis in the European Holocene II: taphonomic and environmental considerations

We have applied cluster analysis to mercury intrusion porosimetry data from 219 archaeological bones (121 human and 98 animal) and soil chemistry data from 219 accompanying soil samples (1 per bone sample), to investigate the influence of soil chemistry on bone preservation. The samples chosen for the study were obtained from sites ranging in time from the pre-modern to the Mesolithic and were representative of burial environments across Europe (from the Baltic to the Mediterranean). These results represent the single largest database for archaeological bone preservation in the European Holocene to date and demonstrate the potential for large-scale diagenetic studies to help develop long term preservation strategies for our European heritage. Despite the variety of sites and environments, bones could be categorised into only four main diagenetic types. Furthermore, soil chemistry appears to significantly affect only one type of preservation, the pathway characterised by loss of mineral. In neutral to basic soils, taphonomy and in particular the differences between the treatment of human and animal remains, becomes the dominating factor in determining preservation. Using these results, strategies for heritage management of archaeological sites can be suggested; grouping sites into those requiring immediate excavation and those where in situ preservation is viable.     

Food for thought: using game cameras to better understand the movement of bones by scavenging in archaeological faunal assemblages

This paper questions our understanding of the movement of bones by animal scavengers in the archaeological record. Since assumptions regarding the effects of animal scavenging shape final interpretations of skeletal element frequencies in archaeological faunal assemblages, they are important for our understanding and reconstruction of ancient human behaviour. The results of a 4-year actualistic kangaroo scavenging study from Australia are used to question our understanding of the movement of the bone by contrasting visual data captured by motion-activated digital game cameras with traditional taphonomic studies using skeletal element frequencies. Game cameras are commonly used by ecologists to capture the behaviour of living species but have not yet been used in experimental archaeology where visually documenting animal scavenging behaviour can be used to understand the movement of carcasses and individual bones. Results suggest that traditional zooarchaeological analyses may not be accurate indicators of hunted versus scavenged prey in archaeological faunal assemblages. Moreover, they most certainly fail to document the entire suite of animals scavenging a carcass. These implications are discussed with particular reference to the ability to definitively ascertain the role of humans in the megafaunal extinction debate in Australia.     

The Finishing Technique of the Stone Monuments of Persepolis: Further Studies and New Findings Through the Use of Non‐Destructive Analytical Techniques

The studies on the finishing technique of the stone monuments in Persepolis (Iran) are part of the archaeological project jointly launched in 2008 by Iran and Italy, named ‘From Palace to Town’. The first experimental results, obtained on a very limited number of samples, revealed that the Achaemenid builders and sculptors used a white pigment, a kind of bone white, calcium fluorapatite, obtained by burning animal bones, to hide the dark grey colour of the stone. In order to verify these unexpected results, a new campaign was implemented to analyse a much larger number of samples. XRF spectrometry, a non‐destructive technique, was used and the experimental results were further elaborated by PCA. The presence of a white superficial layer was confirmed, and the use of fluorapatite was confirmed as well, but only on monuments attributed to the Xerxes period or later, while in the earlier monuments the white layer was obtained using gypsum.     

Breaking Bones to Obtain Marrow: A Comparative Study between Percussion by Batting Bone on an Anvil and Hammerstone Percussion

The fat‐ and nutrient‐rich marrow of animal bones can be extracted using different techniques. Passive hammerstone percussion has been the primary focus of experimental bone breaking and the main analogy to understand archaeological bone breakage. Here, the term ‘passive’ is applied because the bone to be broken passively receives the impact from a hammerstone. In addition to this technique, there is another bone‐breaking method that also requires direct percussion, but in an active way. This method is percussion by ‘batting’, in which the bone is actively hit against an anvil until the bone breaks. This technique has rarely been considered at an experimental level and, therefore, has been omitted in the majority of the archaeological interpretations of faunal assemblages with pre‐use of fire technologies. In this study, we attempt to analytically characterize this type of bone‐breaking technique through a systematic comparison with hammerstone percussion. The applied statistical tests will allow us to distinguish some diagnostic modifications, such as the outlines of the fracture planes and the type of notches or their location with respect to the longitudinal axis of the bone. These features and their proportions allow the consideration of the use of this technique in Pleistocene anthropogenic faunal assemblages.     

Bone diagenesis in the European Holocene I: patterns and mechanisms

Diagenetic changes in archaeological bone are known to influence the data derived from such material and have thus been the subject of numerous studies. A number of general trends have been observed, but many of the processes that occur are still not fully understood. We present here the analysis of 195 bones excavated from 32 sites in five different countries from Eurasia characterized using 10 simple diagenetic parameters. The results reveal that most European Holocene archaeological bone can be categorized by only four main diagenetic states related to three distinct trajectories that describe more than 60% of the variation in these parameters. Given the potential amount of variation in the dataset the small number of diagenetic pathways is surprising, but highlights the large importance of a few key factors that influence bone diagenesis. Mercury intrusion porosimetry is a key technique for identifying modes of degradation.     

Quantifying histological changes in archaeological bones using BSE–SEM image analysis

Recent years have seen rapid developments in the understanding of diagenetic changes to archaeological bones. In particular, the degradation or preservation of proteins and other biomolecules has been explored using an increasingly sophisticated battery of analytical techniques. Problems remain, however, in correlating these parameters with physical changes to bone that may be observed microscopically. This is due, in part, to the problems in reproducibly quantifying histological changes to archaeological bone. This paper introduces a novel method for the accurate quantification of these changes employing image analysis of SEM images. Self–consistency of results was tested using measurements of total calcium content at different magnifications. The term ‘bioerosion index’ is suggested for the measured parameter.     

Diagenesis and survival of osteocalcin in archaeological bone

It has been demonstrated that the protein osteocalcin can survive in bone in the archaeological record, and postulated that it has the potential to survive over geological time periods. The precise mechanism for this longevity of survival is not yet fully understood, and has not been extensively studied in comparison to other diagenetic aspects of archaeological bone. We report a comparison between osteocalcin survival and the state of preservation of more than 60 bones from 14 archaeological sites. The amount of osteocalcin, assayed immunologically, was compared with diagenetic parameters that measure: the amount of ‘collagen’ in the bone, the mineral changes, the porosity, and the histological preservation of the material. The findings indicate that microbial taphonomy and mineral alteration of bone have a profoundly damaging effect on the preservation of osteocalcin.     

Examining histology to identify burned bone

Early research suggests that examination of the microscopic internal structure is a valid method for distinguishing burned from unburned bone in the archaeological record. This study compares burned and unburned modern bones with archaeological bones from Sibudu Cave (ca. 60,000 years ago) and Cave of Hearths (over 200,000 years ago) to more fully describe the heat-induced histological changes to bone. We also explore the effects of diagenesis on those changes to determine if histological evidence of burning preserves through fossilisation and diagenetic processes and can be successfully used to identify ancient burning. Application of this technique can help in addressing various issues, including the origins of controlled use of fire and understanding animal butchery and disposal.     

Dietary Stress and Animal Resource Use at the Postclassic Maya city,Mayapán (Mexico)

ABSTRACT

Environmental changes resulting in drought and reductions in the availability of animal resources during the Late Classic Maya have been linked with the Maya ‘collapse’. Decreases in availability of dietary staples such as artiodactyls, and particularly white-tailed deer, during the Late Classic period would have placed food stress on populations during later periods. To test this hypothesis, here bone breakage patterns are examined at the Postclassic Maya city, Mayapán, to assess whether artiodactyl bones were being intensively processed for bone fats (marrow and grease). Fragmentation morphology, size and surface markings, along with skeletal part representation and distribution of large mammal bones were recorded for bone assemblages from several houselots. Evidence suggests the Maya were likely utilising bone marrow from artiodactyls but not intensively and they were not extracting bone grease. These results indicate that decreased accessibility to artiodactyls during the Postclassic was not causing high levels of dietary stress for the Maya at Mayapán, which is consistent with recent evidence demonstrating dietary consistency during the Postclassic in northern Yucatan.     

BUTCHERING PATTERNS AND SPATIAL DISTRIBUTION OF FAUNAL ANIMAL REMAINS CONSUMED AT THE LOS MILLARES CHALCOLITHIC SETTLEMENT (SANTA FE DE MONDÚJAR,ALMERÍA,SPAIN)

The archaeological settlement of Los Millares (Santa Fe de Mondújar, Almería) is located in the Mediterranean coastal area of southern Spain. This archaeological site constitutes one of the most important settlements belonging to the Copper Age in the Iberian Peninsula and has given its name to the ‘millariense’ culture. The settlement has been completely excavated, yielding major archaeological faunal remains, with 27,426 bone fragments classified by researchers from Munich University (Germany). In this paper, we apply different statistical methods (mainly χ² analysis) to study the spatial distribution of bones from domestic and wild animals, reconstructing the patterns of appearance within specific functional spaces. These functions can be associated with meat consumption (sites to cut the animals into small pieces, areas where the meat was eaten, garbage sites, etc.) and the production of handmade objects (bone tools, stone tools, etc.). The results show different spatial distributions of faunal remains within the areas of the settlement, according to the animal species and particular parts of the animal skeleton, as well as the age and the sex of individuals. The findings reflect social behaviour that relates the consumption of certain species to a specific sector of population, and such behaviour can be discerned in the animal remains. Moreover, there is evidence regarding economic matters, such as meat production and the exchange of animals, which require further research.     

A Dog Skin from Asthall

A group of associated dog bones recovered from a Romano-British burial, probably late, has been examined in the course of the analysis of the full bone assemblage from this settlement site. The clarity of the deposition, the interpretation of the relationship between the human and animal bone, and the wider background of whole animal skins in archaeological contexts is discussed.     

Neolithic pigs from Durrington Walls,Wiltshire, England: a biometrical database

The large assemblage of animal remains from Late Neolithic Durrington Walls (Wiltshire, England) provides an opportunity to examine patterns of variability in the measurements of pig bones and teeth in a large archaeological sample, and to propose a set of ‘standard’ measurements to be used as a comparison with other European sites. The results provide a basis for suggesting which measurements are best suited to tackle different questions, such as the separation of populations, sexes and age groups.     

Effects of Sodium Hydroxide Treatment and Ultrafiltration on the Removal of Humic Contaminants from Archaeological Bone

This study compared bone collagen extraction techniques that included treatment with sodium hydroxide and 30 kDa ultrafilters using a set of well‐preserved, humic‐contaminated archaeological marine mammal bones. Treatment with sodium hydroxide was effective at removing humic contaminants from archaeological bone, although yields were significantly decreased. Yields were also significantly decreased by ultrafiltration although this study produced no evidence that 30 kDa ultrafilters were effective at selectively removing humic contaminants from archaeological bone. The combination of sodium hydroxide treatment and ultrafiltration did not produce superior results to the treatment involving only sodium hydroxide. Archaeological samples exhibiting darker colouration indicative of humic contamination should be treated with sodium hydroxide to remove these contaminants. Copyright © 2017 John Wiley & Sons, Ltd.     

Sub‐micron spongiform porosity is the major ultra‐structural alteration occurring in archaeological bone

Total pore volume and pore size distribution are indicators of the degree of post‐mortem modification of bone. Direct measurements of pore size distribution in archaeological bones using mercury intrusion porosimetry (HgIP) and back scattered scanning electron microscopy (BSE‐SEM) reveal a common pattern in the changes seen in degraded bone as compared to modern samples. The estimates of pore size distribution from HgIP and direct measurement from the BSE‐SEM images show remarkable correspondence. The coupling of these two independent approaches has allowed the diagenetic porosity changes in human archaeological bone in the >0.01 µm range to be directly imaged, and their relationship to pre‐existing physiological pores to be explored. The increase in porosity in the archaeological bones is restricted to two discrete pore ranges. The smaller of these two ranges (0.007–0.1 µm) lies in the range of the collagen fibril (0.1 µm diameter) and is presumably formed by the loss of collagen, whereas the larger pore size distribution is evidence of direct microbial alteration of the bone. HgIP has great potential for the characterization of microbial and chemical alteration of bone. Copyright © 2002 John Wiley & Sons, Ltd.     

Displayed or Concealed? Cross Cultural Evidence for Symbolic and Ritual Activity Depositing Iron Age Animal Bones

Although Iron Age rituals involving the depositing of animal bones in pits have been discussed intensively in the literature, possible cross-cultural and ethnographic parallels for the symbolism of such activity have been neglected. This paper begins to remedy this deficiency. Archaeological and ethnographic examples occur world-wide, especially relating to the symbolism and treatment of animal heads and crania. They support previous arguments that at least some Iron Age bone deposits involved the renewal and protection of fertility, for example those associated with grain storage pits and other archaeological features, perhaps also foundation deposits, especially at later periods.     

‘Rid grasse of bones’: A taphonomic study of the bones from midden deposits at the Neolithic and Bronze age site of Runnymede,Surrey, England

Runnymede has large samples of Neolithic and Late Bronze Age animal bones, with contrasting preservation conditions in both periods. The bone evidence has been used to interpret the formation of the site deposits. There are few articulated bones, and no joins were found in butchered bone, indicating that the area studied did not contain primary refuse. Various aspects of bone alteration have been analysed: (i) the proportion of bones with very good surface preservation was high in the in situ Neolithic excavation units and the basal Bronze Age midden, but bones in the upper units were mostly eroded. These units are reworked flood deposits. The greater degree of fragmentation of the bone in the reworked units has been quantified, using a system of recording the ‘zones’ present on each bone, which allows calculation of the fraction present. It is also demonstrated that the reworked units contain a lower proportion of identified bones and a higher proportion of teeth and iaws than the units with well-preserved bone, (ii) Quantification of canid gnawing shows, unexpectedly, that more was recorded on well-preserved bone. Thus recognition of gnawing depends on bone condition. This also confirms that most of the erosion of the bone surface is a post-depositional phenomenon. The sequence of activities is therefore interpreted as follows: meat was cooked and consumed, and the bones discarded for the dogs. At a later stage, larger bones were picked up and thrown away in the river or midden. Some ethnographic examples of periodic cleaning of farming settlements are cited.